The document discusses the structure and functions of plant stems. It begins by defining stems and describing their main functions: support, conduction, and production of new living tissue. It then discusses the external morphology of stems, including nodes, internodes, buds, and other features. The internal structure is also examined, focusing on the shoot apex organization and primary meristems that give rise to primary tissues like epidermis, ground tissue, and vascular tissues. Primary growth and tissue development in dicot and monocot stems is contrasted. Finally, the document covers secondary growth, which occurs in woody stems through the activity of the vascular cambium and cork cambium.
After double fertilization and triple fusion, the zygote secretes a cellulose wall and divides into two cells - an upper embryonal cell and lower suspensor cell. The embryonal cell divides into eight octant cells which then divide further, forming a surface layer of dermatogen cells and an inner embryonal mass. The dermatogens and embryonal mass cells continue dividing and differentiating to form the various parts of the embryo, including the plumule, cotyledons, radicle, and hypocotyledons.
This document presents information about plant anatomy and plant tissues. It discusses the three main types of plant tissues: meristems, permanent tissues, and secretory tissues. It focuses on describing meristems, which are tissues composed of actively dividing cells. Meristems are classified based on their origin, location in the plant, and differentiation. The main types of meristems are primary meristems found at tips of roots and stems, secondary meristems that develop later and allow thickening, and lateral meristems involved in secondary growth.
Stomata are tiny pores on plant leaves that open and close to regulate gas exchange. They are bordered by a pair of guard cells that swell and contract to control the opening width. During the day, photosynthesis in guard cells produces sugar, increasing their turgor pressure and causing stomata to open. At night, the lack of photosynthesis allows starch to accumulate, decreasing turgor pressure and prompting stomatal closure. Potassium ion transport is also important - influx of K+ into guard cells during the day increases their solute content and turgor, while efflux at night decreases turgor. Together, these mechanisms allow plants to control gas exchange through stomatal openings in response to light
The stem consists of nodes and internodes. Axillary and apical buds form branches and elongate the shoot tip. The shoot apex contains a dome-shaped apical meristem that produces leaves and axillary buds. It is organized into an outer layer called the tunica and inner region called the corpus. Leaf primordia develop from the sides of the apical meristem.
This document compares the leaf anatomy of dicots and monocots. Dicot leaves have a dorsiventral orientation with stomata on the upper epidermis. Their mesophyll is differentiated into palisade and spongy parenchyma, and their vascular bundles are surrounded by bundle sheath cells made of collenchyma. Monocot leaves have an isobilateral orientation with stomata on both epidermis. Their mesophyll is not differentiated and contains bulliform cells that control leaf curling. Their vascular bundles are surrounded by sclerenchyma bundle sheath cells.
The document discusses the root-stem transition zone in plants. It begins by explaining that the root has a radial vascular structure while the stem has a conjoint structure, so there must be a region where these structures merge. This region is called the root-stem transition zone. The document then describes four types of root-stem transitions (Fumaria, Cucurbita, Lathyrus, and Anemarrhena) which differ in how the xylem and phloem structures divide and rearrange as they transition from root to stem. Finally, it notes that the transition zone represents a different internal arrangement than the root or stem and reflects different evolutionary stages in the development of the vascular system.
After double fertilization and triple fusion, the zygote secretes a cellulose wall and divides into two cells - an upper embryonal cell and lower suspensor cell. The embryonal cell divides into eight octant cells which then divide further, forming a surface layer of dermatogen cells and an inner embryonal mass. The dermatogens and embryonal mass cells continue dividing and differentiating to form the various parts of the embryo, including the plumule, cotyledons, radicle, and hypocotyledons.
This document presents information about plant anatomy and plant tissues. It discusses the three main types of plant tissues: meristems, permanent tissues, and secretory tissues. It focuses on describing meristems, which are tissues composed of actively dividing cells. Meristems are classified based on their origin, location in the plant, and differentiation. The main types of meristems are primary meristems found at tips of roots and stems, secondary meristems that develop later and allow thickening, and lateral meristems involved in secondary growth.
Stomata are tiny pores on plant leaves that open and close to regulate gas exchange. They are bordered by a pair of guard cells that swell and contract to control the opening width. During the day, photosynthesis in guard cells produces sugar, increasing their turgor pressure and causing stomata to open. At night, the lack of photosynthesis allows starch to accumulate, decreasing turgor pressure and prompting stomatal closure. Potassium ion transport is also important - influx of K+ into guard cells during the day increases their solute content and turgor, while efflux at night decreases turgor. Together, these mechanisms allow plants to control gas exchange through stomatal openings in response to light
The stem consists of nodes and internodes. Axillary and apical buds form branches and elongate the shoot tip. The shoot apex contains a dome-shaped apical meristem that produces leaves and axillary buds. It is organized into an outer layer called the tunica and inner region called the corpus. Leaf primordia develop from the sides of the apical meristem.
This document compares the leaf anatomy of dicots and monocots. Dicot leaves have a dorsiventral orientation with stomata on the upper epidermis. Their mesophyll is differentiated into palisade and spongy parenchyma, and their vascular bundles are surrounded by bundle sheath cells made of collenchyma. Monocot leaves have an isobilateral orientation with stomata on both epidermis. Their mesophyll is not differentiated and contains bulliform cells that control leaf curling. Their vascular bundles are surrounded by sclerenchyma bundle sheath cells.
The document discusses the root-stem transition zone in plants. It begins by explaining that the root has a radial vascular structure while the stem has a conjoint structure, so there must be a region where these structures merge. This region is called the root-stem transition zone. The document then describes four types of root-stem transitions (Fumaria, Cucurbita, Lathyrus, and Anemarrhena) which differ in how the xylem and phloem structures divide and rearrange as they transition from root to stem. Finally, it notes that the transition zone represents a different internal arrangement than the root or stem and reflects different evolutionary stages in the development of the vascular system.
ROOT HAIR DEVELOPMENT IN PLANTS:
structure and development of root hairs, Initiation and molecular genetics of root hair, functions of root hairs.
complete topic from authentic websites. Essential for for all life science students.
1. The document discusses various types of anomalous structures that can occur in dicot stems, including the presence of medullary or cortical bundles, absence of vessels, abnormal cambium activity, presence of phloem bundles or scattered vascular bundles, and presence of interxylary or included phloem.
2. It provides examples of these anomalies in specific plants like Boerhaavia, Achyranthus, Bignonia, Amaranthus, Mirabilis, and Leptadenia. In these plants, the anomalous structures arise due to abnormal primary structure, abnormal secondary growth, or abnormal cambium behavior.
3. The secondary growth in some plants like Boerhaavia, Achyran
Vascular Cambium & Seasonal activity & its Role in Stem & RootFatima Ramay
Vascular Cambium & Seasonal activity & its Role in Stem & Root:
The vascular cambium (pl. cambia or cambiums) is a lateral meristem in the vascular tissue of plants.
The vascular cambium is a cylindrical layer of cambium that runs through the stem of a plant that undergoes secondary growth.
In Dicots:
The vascular cambium is in dicot stems and roots, located between the xylem and the phloem in the stem and root of a vascular plant, and is the source of both the secondary xylem growth (inwards, towards the pith) and the secondary phloem growth (outwards).
In Monocots:
Monocot stems, such as corn, palms and bamboos, do not have a vascular cambium and do not exhibit secondary growth by the production of concentric annual rings. They cannot increase in girth by adding lateral layers of cells as in conifers and woody dicots.
Cambium of some plants remains active for the entire period of their life, i.e., cambial cells divide and resulting cells mature to form xylem and phloem elements.
This type of seasonal activity usually found in the plants present in the tropical regions, and not all plants show cambial activity.
Percentage of ringless trees in the rain forests of;India : 75%Amazon : 43%Malaysia : 15%
In regions with definite seasonal climate; seasonal activity of cambium ceased with onset of unfavorable conditions; In Autumn, it enters the dormant state and lasts for the end of summer; In Spring, cambium again becomes active.
Duration of cambial activity is also affected by day-length, e.g., In Robinia pseudoacacia, cambium is dormant under short-day condition.
The cambium cells formed in circular in cross section from the beginning onwards.
The cambial ring is partially primary (fascicular cambium) and partially secondary (interfascicular cambium).
Periderm originates from the cortical cells (extra stelar in origin).
In Dicot stem, for mechanical support xylem is with comparatively smaller vessels, greater fibers and less parenchyma.
More amount of cork is produces for protection.
Lenticels on periderm are very prominent.
The cambial ring formed is wavy in the beginning and later becomes circular.
The cambium ring is completely secondary in origin.
Periderm originates from the pericycle (intra stelar in origin).
In Dicot root, xylem is with big thin walled vessels with few fibers and more parenchyma.
Less amount of cork is produced as root is underground.
Lenticels on periderm are not very prominent.
This document discusses gibberellins, a class of plant hormones. It was first discovered in 1928 by a Japanese scientist who observed rice plants infected by the fungus Gibberella fujikuroi showed excessive stem elongation. There are over 70 known forms of gibberellins that regulate various plant developmental processes such as stem elongation, germination, flowering, and fruit development. Gibberellins are widely distributed in plants and are involved in many physiological roles including stem elongation, bolting, seed germination, breaking bud and tuber dormancy, parthenocarpy, and flowering.
Vascular tissue in plants transports water and nutrients throughout the plant. It consists of two main components: xylem and phloem. Xylem transports water and minerals from the roots to other parts of the plant. It consists mainly of dead cells. Phloem transports organic nutrients made during photosynthesis, such as sugars, throughout the plant. Unlike xylem, phloem consists of living cells.
This document summarizes the development of the male gametophyte or microsporogenesis in plants. It begins with an introduction describing how microspores develop into a vegetative cell and generative cell. It then discusses how the generative cell undergoes mitosis to form two sperm cells. The document proceeds to describe the formation of the vegetative and generative cells from the microspore, including their sizes, shapes and contents. It concludes by discussing the development of the pollen wall, which has two layers - the outer exine and inner intine.
This document discusses anomalous secondary growth in plants. It begins by defining anomalous secondary growth as a deviation from normal cambial activity in dicots. There are two types of anomalous growth: adaptive and non-adaptive. Adaptive growth includes woody climbers, while non-adaptive includes plants like Rumex and Chenopodium.
The document then describes two types of anomalous secondary growth: 1) abnormal behavior of the normal cambium and 2) abnormal behavior of an abnormal cambium. In type 1, the cambium forms vascular tissue only in bundle regions or produces more vascular tissue in bundles, seen in plants like Cucurbita and Bignonia. In type 2, accessory cambia form rings of vascular bundles
this presentation describes the concept of growth and development of plants in details. it explains different types and phases of growth. it also contain notes on growth rate that ie arithmetic & geometric. Growth curve and growth requirements are also well explained in this ppt. it also define differentiation, dedifferentiation and redifferentiation.
Water and solute transport in plant pptLaith Huseen
This document provides an overview of water and solute transport in plants. It discusses that water and minerals absorbed by roots are transported upward through the xylem, while sugars produced by photosynthesis are exported from leaves to other plant parts via the phloem. Both passive transport mechanisms like diffusion and osmosis, as well as active transport requiring ATP, facilitate this movement. Water potential, determined by solute concentration and pressure, drives the direction of water movement. Short-distance transport occurs through diffusion, plasmodesmata, and the apoplast, while long-distance transport relies on bulk flow through xylem and phloem. Transpiration creates a pull that draws water up the xylem, while pressure
Double fertilization is the process found in angiosperms in which out of the two male gametes released inside the embryo sac, one fuses with the egg cell (syngamy) and another fuse with secondary nucleus (triple fusion).
The document summarizes the key components and functions of xylem and phloem tissue in plants. Xylem tissue conducts water and minerals throughout the plant and is composed of tracheids and vessels. Phloem tissue conducts sugars and transports them from leaves to other plant parts. Phloem consists of sieve tubes made of elongated living cells called sieve elements connected end to end to form columns. Each sieve element has an associated companion cell that provides energy and nutrients to keep the sieve element alive via plasmodesmata.
This document discusses abnormal or anomalous secondary growth in plants. It defines secondary growth as an increase in plant girth due to vascular cambium or cork cambium. Anomalous secondary growth does not follow the normal pattern of a single vascular cambium producing xylem internally and phloem externally. Some examples given of plants that exhibit anomalous secondary growth include Bougainvillea, which forms multiple cambium rings outside the oldest phloem, and monocots like Dracaena which can exhibit secondary growth in roots. The document also describes different types of anomalous secondary growth that can occur in dicot stems due to abnormal cambium position or activity.
1. Plant embryogenesis begins with an asymmetric cell division forming an apical and basal cell, followed by further cell divisions forming a rudimentary plant body with an embryonic axis and cotyledons.
2. Key genes involved in embryo development establish the apical-basal and radial patterns, and mutations in these genes disrupt proper embryo formation.
3. In angiosperms, embryo development typically arrests after meristems and cotyledons form, with the seed coat enclosing the dormant embryo until germination conditions are met.
This document discusses the physiology and ecology of nitrogen and potassium in plants. It outlines that potassium regulates stomata opening and closing to control CO2 uptake and is essential for ATP production and osmoregulation. Potassium deficiency can result in chlorosis, stunted growth, and reduced drought resistance. Nitrogen is a major component of chlorophyll and nucleic acids and is required for photosynthesis. Both nitrogen and potassium are involved in numerous enzyme and metabolic processes important for plant growth, reproduction, and overwintering. Their uptake and cycling in soils and plants are important to consider for agricultural systems.
1. Annual rings in plants are formed due to seasonal variations in the activity of vascular cambium. Spring wood formed during periods of high cambium activity is lighter in color and more porous than autumn wood.
2. One annual ring is formed each year, consisting of one ring of spring wood and one of autumn wood. Counting the number of annual rings can determine the age of the tree.
3. Annual rings are most distinct in temperate deciduous trees, and least distinct in tropical plants and trees near the seashore with constant climates.
The document discusses the importance and properties of water for plant physiology. Water is essential for all living organisms as cells are composed of 70-95% water. The unique properties of water, such as its polarity, hydrogen bonding, high heat capacity and solubility allow it to perform critical functions for plants such as transporting nutrients, regulating temperature, and supporting biochemical reactions like photosynthesis. These properties, including water's ability to absorb large amounts of heat before changing state, make it uniquely suited to support life.
Leaf structure, adaptations, development Jasmine Brar
Leaves develop from leaf primordia in the shoot apical meristem. They have three main parts - the lamina, petiole, and leaf base. The lamina is the broad, typically green, photosynthetic part of the leaf. Leaves come in many shapes and sizes and have a variety of venation patterns and arrangements on the stem. Leaves also have many modified forms that take on additional functions like storage or reproduction.
The document summarizes plant tissues and organs. It describes that plants have organs composed of tissues which are made of cells with specific functions. The three main plant organs are roots, stems, and leaves. These organs are divided into the root system and shoot system. The document then discusses the different types of tissues that make up these organs, including dermal tissue (epidermis, roots hairs, trichomes), ground tissues (parenchyma, collenchyma, sclerenchyma), and vascular tissues (xylem, phloem). It provides details on the structure and function of each type of tissue.
Stem structure varies between monocots and dicots. Dicot stems have a ring of vascular bundles and pith in the center, while monocot stems have vascular bundles throughout. The stem is made up of dermal, ground, and vascular tissues. Dermal tissue covers and protects the stem, ground tissue fills spaces, and vascular tissue provides transport. External stem features include lenticels, buds, and leaf scars. Internally, stems have an apical meristem, epidermis, cortex, vascular bundles made of xylem and phloem, and a pith in dicots.
ROOT HAIR DEVELOPMENT IN PLANTS:
structure and development of root hairs, Initiation and molecular genetics of root hair, functions of root hairs.
complete topic from authentic websites. Essential for for all life science students.
1. The document discusses various types of anomalous structures that can occur in dicot stems, including the presence of medullary or cortical bundles, absence of vessels, abnormal cambium activity, presence of phloem bundles or scattered vascular bundles, and presence of interxylary or included phloem.
2. It provides examples of these anomalies in specific plants like Boerhaavia, Achyranthus, Bignonia, Amaranthus, Mirabilis, and Leptadenia. In these plants, the anomalous structures arise due to abnormal primary structure, abnormal secondary growth, or abnormal cambium behavior.
3. The secondary growth in some plants like Boerhaavia, Achyran
Vascular Cambium & Seasonal activity & its Role in Stem & RootFatima Ramay
Vascular Cambium & Seasonal activity & its Role in Stem & Root:
The vascular cambium (pl. cambia or cambiums) is a lateral meristem in the vascular tissue of plants.
The vascular cambium is a cylindrical layer of cambium that runs through the stem of a plant that undergoes secondary growth.
In Dicots:
The vascular cambium is in dicot stems and roots, located between the xylem and the phloem in the stem and root of a vascular plant, and is the source of both the secondary xylem growth (inwards, towards the pith) and the secondary phloem growth (outwards).
In Monocots:
Monocot stems, such as corn, palms and bamboos, do not have a vascular cambium and do not exhibit secondary growth by the production of concentric annual rings. They cannot increase in girth by adding lateral layers of cells as in conifers and woody dicots.
Cambium of some plants remains active for the entire period of their life, i.e., cambial cells divide and resulting cells mature to form xylem and phloem elements.
This type of seasonal activity usually found in the plants present in the tropical regions, and not all plants show cambial activity.
Percentage of ringless trees in the rain forests of;India : 75%Amazon : 43%Malaysia : 15%
In regions with definite seasonal climate; seasonal activity of cambium ceased with onset of unfavorable conditions; In Autumn, it enters the dormant state and lasts for the end of summer; In Spring, cambium again becomes active.
Duration of cambial activity is also affected by day-length, e.g., In Robinia pseudoacacia, cambium is dormant under short-day condition.
The cambium cells formed in circular in cross section from the beginning onwards.
The cambial ring is partially primary (fascicular cambium) and partially secondary (interfascicular cambium).
Periderm originates from the cortical cells (extra stelar in origin).
In Dicot stem, for mechanical support xylem is with comparatively smaller vessels, greater fibers and less parenchyma.
More amount of cork is produces for protection.
Lenticels on periderm are very prominent.
The cambial ring formed is wavy in the beginning and later becomes circular.
The cambium ring is completely secondary in origin.
Periderm originates from the pericycle (intra stelar in origin).
In Dicot root, xylem is with big thin walled vessels with few fibers and more parenchyma.
Less amount of cork is produced as root is underground.
Lenticels on periderm are not very prominent.
This document discusses gibberellins, a class of plant hormones. It was first discovered in 1928 by a Japanese scientist who observed rice plants infected by the fungus Gibberella fujikuroi showed excessive stem elongation. There are over 70 known forms of gibberellins that regulate various plant developmental processes such as stem elongation, germination, flowering, and fruit development. Gibberellins are widely distributed in plants and are involved in many physiological roles including stem elongation, bolting, seed germination, breaking bud and tuber dormancy, parthenocarpy, and flowering.
Vascular tissue in plants transports water and nutrients throughout the plant. It consists of two main components: xylem and phloem. Xylem transports water and minerals from the roots to other parts of the plant. It consists mainly of dead cells. Phloem transports organic nutrients made during photosynthesis, such as sugars, throughout the plant. Unlike xylem, phloem consists of living cells.
This document summarizes the development of the male gametophyte or microsporogenesis in plants. It begins with an introduction describing how microspores develop into a vegetative cell and generative cell. It then discusses how the generative cell undergoes mitosis to form two sperm cells. The document proceeds to describe the formation of the vegetative and generative cells from the microspore, including their sizes, shapes and contents. It concludes by discussing the development of the pollen wall, which has two layers - the outer exine and inner intine.
This document discusses anomalous secondary growth in plants. It begins by defining anomalous secondary growth as a deviation from normal cambial activity in dicots. There are two types of anomalous growth: adaptive and non-adaptive. Adaptive growth includes woody climbers, while non-adaptive includes plants like Rumex and Chenopodium.
The document then describes two types of anomalous secondary growth: 1) abnormal behavior of the normal cambium and 2) abnormal behavior of an abnormal cambium. In type 1, the cambium forms vascular tissue only in bundle regions or produces more vascular tissue in bundles, seen in plants like Cucurbita and Bignonia. In type 2, accessory cambia form rings of vascular bundles
this presentation describes the concept of growth and development of plants in details. it explains different types and phases of growth. it also contain notes on growth rate that ie arithmetic & geometric. Growth curve and growth requirements are also well explained in this ppt. it also define differentiation, dedifferentiation and redifferentiation.
Water and solute transport in plant pptLaith Huseen
This document provides an overview of water and solute transport in plants. It discusses that water and minerals absorbed by roots are transported upward through the xylem, while sugars produced by photosynthesis are exported from leaves to other plant parts via the phloem. Both passive transport mechanisms like diffusion and osmosis, as well as active transport requiring ATP, facilitate this movement. Water potential, determined by solute concentration and pressure, drives the direction of water movement. Short-distance transport occurs through diffusion, plasmodesmata, and the apoplast, while long-distance transport relies on bulk flow through xylem and phloem. Transpiration creates a pull that draws water up the xylem, while pressure
Double fertilization is the process found in angiosperms in which out of the two male gametes released inside the embryo sac, one fuses with the egg cell (syngamy) and another fuse with secondary nucleus (triple fusion).
The document summarizes the key components and functions of xylem and phloem tissue in plants. Xylem tissue conducts water and minerals throughout the plant and is composed of tracheids and vessels. Phloem tissue conducts sugars and transports them from leaves to other plant parts. Phloem consists of sieve tubes made of elongated living cells called sieve elements connected end to end to form columns. Each sieve element has an associated companion cell that provides energy and nutrients to keep the sieve element alive via plasmodesmata.
This document discusses abnormal or anomalous secondary growth in plants. It defines secondary growth as an increase in plant girth due to vascular cambium or cork cambium. Anomalous secondary growth does not follow the normal pattern of a single vascular cambium producing xylem internally and phloem externally. Some examples given of plants that exhibit anomalous secondary growth include Bougainvillea, which forms multiple cambium rings outside the oldest phloem, and monocots like Dracaena which can exhibit secondary growth in roots. The document also describes different types of anomalous secondary growth that can occur in dicot stems due to abnormal cambium position or activity.
1. Plant embryogenesis begins with an asymmetric cell division forming an apical and basal cell, followed by further cell divisions forming a rudimentary plant body with an embryonic axis and cotyledons.
2. Key genes involved in embryo development establish the apical-basal and radial patterns, and mutations in these genes disrupt proper embryo formation.
3. In angiosperms, embryo development typically arrests after meristems and cotyledons form, with the seed coat enclosing the dormant embryo until germination conditions are met.
This document discusses the physiology and ecology of nitrogen and potassium in plants. It outlines that potassium regulates stomata opening and closing to control CO2 uptake and is essential for ATP production and osmoregulation. Potassium deficiency can result in chlorosis, stunted growth, and reduced drought resistance. Nitrogen is a major component of chlorophyll and nucleic acids and is required for photosynthesis. Both nitrogen and potassium are involved in numerous enzyme and metabolic processes important for plant growth, reproduction, and overwintering. Their uptake and cycling in soils and plants are important to consider for agricultural systems.
1. Annual rings in plants are formed due to seasonal variations in the activity of vascular cambium. Spring wood formed during periods of high cambium activity is lighter in color and more porous than autumn wood.
2. One annual ring is formed each year, consisting of one ring of spring wood and one of autumn wood. Counting the number of annual rings can determine the age of the tree.
3. Annual rings are most distinct in temperate deciduous trees, and least distinct in tropical plants and trees near the seashore with constant climates.
The document discusses the importance and properties of water for plant physiology. Water is essential for all living organisms as cells are composed of 70-95% water. The unique properties of water, such as its polarity, hydrogen bonding, high heat capacity and solubility allow it to perform critical functions for plants such as transporting nutrients, regulating temperature, and supporting biochemical reactions like photosynthesis. These properties, including water's ability to absorb large amounts of heat before changing state, make it uniquely suited to support life.
Leaf structure, adaptations, development Jasmine Brar
Leaves develop from leaf primordia in the shoot apical meristem. They have three main parts - the lamina, petiole, and leaf base. The lamina is the broad, typically green, photosynthetic part of the leaf. Leaves come in many shapes and sizes and have a variety of venation patterns and arrangements on the stem. Leaves also have many modified forms that take on additional functions like storage or reproduction.
The document summarizes plant tissues and organs. It describes that plants have organs composed of tissues which are made of cells with specific functions. The three main plant organs are roots, stems, and leaves. These organs are divided into the root system and shoot system. The document then discusses the different types of tissues that make up these organs, including dermal tissue (epidermis, roots hairs, trichomes), ground tissues (parenchyma, collenchyma, sclerenchyma), and vascular tissues (xylem, phloem). It provides details on the structure and function of each type of tissue.
Stem structure varies between monocots and dicots. Dicot stems have a ring of vascular bundles and pith in the center, while monocot stems have vascular bundles throughout. The stem is made up of dermal, ground, and vascular tissues. Dermal tissue covers and protects the stem, ground tissue fills spaces, and vascular tissue provides transport. External stem features include lenticels, buds, and leaf scars. Internally, stems have an apical meristem, epidermis, cortex, vascular bundles made of xylem and phloem, and a pith in dicots.
Vascular plants that reproduce via spores rather than seeds are described. They have vascular tissues like tracheids and sieve cells. Four divisions of vascular spore plants are discussed: Psilotophyta, Lycophyta, Pterophyta (ferns), and Sphenophyta (horsetails). Ferns and horsetails are described in more detail, including their branching patterns, leaf and root structures, and vascular anatomy.
This document provides an overview of plant and animal tissues. It discusses the three primary plant organs - leaves, stems, and roots. It then covers the two main categories of plant tissues: meristematic and permanent. Meristematic tissues include apical, intercalary, and lateral meristems, which allow for growth. Permanent tissues such as epidermis, xylem, phloem and fibers are also described. The document also summarizes the four main types of animal tissue - epithelium, connective, muscle, and nervous tissue - and provides examples of each type.
This document discusses plant tissues and how they are organized in plant structures like stems, roots, and leaves. It describes the basic tissue types found in plants like parenchyma, collenchyma and sclerenchyma, as well as complex tissues like xylem, phloem and epidermis. The chapter also examines how plant tissues develop and are arranged differently between monocots and dicots.
This document discusses plant tissues and how they are organized in plant structures like stems, roots, and leaves. It describes the basic tissue types found in plants like parenchyma, collenchyma and sclerenchyma, as well as complex tissues like xylem, phloem and epidermis. The chapter also examines how plant tissues develop and are arranged differently between monocots and dicots.
Plant tissues fall into two categories: meristematic and permanent. Meristematic tissues are places where cell division occurs and include apical, intercalary, and lateral meristems. Apical meristems are located at shoot and root tips and cause primary growth. Dicots also have lateral meristems, which cause secondary growth and increase stem diameter. Permanent tissues include the epidermis, xylem, phloem, cortex, pith, and fibers. The epidermis covers plant surfaces and contains stomata. Xylem conducts water and phloem transports food. Fibers provide strength and support.
The document summarizes plant tissues and structures. It describes the basic tissues of plants including meristematic tissues that produce new growth, simple tissues like parenchyma and sclerenchyma, and complex tissues like xylem and phloem. It also discusses the shoot and root systems of angiosperms as well as leaf structures and functions. Secondary growth in woody plants is briefly covered.
The document summarizes plant tissues and structures. It describes the basic tissues of plants including meristematic tissues that produce new growth, simple tissues like parenchyma and sclerenchyma, and complex tissues like xylem and phloem. It also discusses the shoot and root systems of angiosperms as well as leaf structures and functions. Secondary growth in plants is explained along with the formation of wood.
This document discusses leaf structure and function. It begins by defining leaves and their basic anatomy. It then covers leaf classification, morphology, histology, and development. The key structures discussed include the epidermis, mesophyll, vascular bundles, petiole, and abscission zone. Gymnosperm and angiosperm leaves are compared in terms of their tissues and support structures. Leaf development starts from the shoot apical meristem and progresses through initiation, outgrowth, and maturation of tissues.
This document provides an overview of botany basics including plant structure and function. It discusses how plants capture sunlight, provide oxygen, participate in water and nutrient cycles. It also outlines plant classifications, life cycles, root, stem, leaf, flower, fruit and seed anatomy. The key areas covered are vascular transport systems, photosynthesis, plant reproduction and how botany is applied in horticulture and agriculture.
1. The document describes the ontogenetic development and anatomy of plant stems.
2. It discusses the primary tissues of stems, including the epidermis, cortex, endodermis, and stele, as well as the nature of stems as herbaceous or woody.
3. The document provides detailed information on the structure and development of vascular bundles, vascular cambium, xylem differentiation, leaf traces, and classification of stele types in plant stems.
Secondary growth occurs in woody stems and roots through the activity of lateral meristems like the vascular cambium and cork cambium. This results in an increase in the stem or root diameter. The vascular cambium divides to produce secondary xylem internally and secondary phloem externally. In dicots, the vascular cambium forms a complete ring. As the stem grows in diameter, tissues inside like pith and medullary rays are compressed. The epidermis may rupture and be replaced by a protective periderm tissue like cork. Lenticels allow gas exchange through the impermeable cork layers. Secondary meristems also function in wound healing through wound cambium and cork formation.
1. Plant tissues are classified as meristematic and permanent tissues. Meristematic tissues are dividing tissues located at specific regions that allow plant growth.
2. Meristematic tissues are further classified as apical, lateral, and intercalary. Permanent tissues are formed when meristematic cells differentiate and take up permanent roles.
3. Common permanent tissues include parenchyma, collenchyma, sclerenchyma, epidermal tissues, xylem and phloem. Epidermal tissues form the plant outer layer and regulate gas exchange through stomata. Xylem and phloem transport water and nutrients.
Tissue is a group of cells that work together to perform a specific function. There are four main types of tissues in animals - epithelial, connective, muscular and nervous tissue. Epithelial tissue covers external and internal surfaces. Connective tissue connects, supports or binds other tissues. Muscular tissue allows for body movement via contraction. Nervous tissue conducts electrical signals throughout the body to coordinate responses.
Plant organs such as roots, stems, and leaves are composed of tissues which are groups of cells that perform specialized functions. The three main tissue types are dermal tissue (epidermis), ground tissue (parenchyma, collenchyma, sclerenchyma), and vascular tissue (xylem and phloem). The epidermis forms the outer protective layer, ground tissues fill the interior and provide support, and vascular tissues transport water, minerals, and organic compounds throughout the plant. Each tissue contains further specialized cell types that contribute to the plant's growth, protection, nutrient transport, and other processes.
Plants have three basic organs - roots, stems, and leaves. Roots anchor the plant and absorb water and minerals, stems provide structure and transport nutrients between roots and leaves, and leaves are the main photosynthetic organ. These organs are composed of tissues including dermal tissue, ground tissue, and vascular tissue. Primary growth lengthens roots and shoots through cell division at apical meristems. Secondary growth in woody plants adds girth through lateral meristems.
"Equisetum" Structural development Reproduction Muhammad ArSlan
The plant body of Equisetum has an underground rhizome and an aerial shoot. The shoot has scale-like leaves arranged in whorls and ridges with stomata located in furrows. It reproduces sexually through antheridia and archegonia on separate gametophytes. Upon fertilization of the egg, the zygote develops into a four-celled embryo that grows into a new sporophyte, with multiple sporophytes potentially developing from a single gametophyte.
Tissue is an organizational level between cells and complete organisms, consisting of groups of cells carrying out specific functions. There are two main types of plant tissue - meristematic and permanent. Meristematic tissue consists of cells that continuously divide, found at growing tips and sides of stems and roots. Permanent tissue has specialized structures and lost ability to divide. Simple permanent tissues include parenchyma, collenchyma, and sclerenchyma. Complex permanent tissues are xylem and phloem, specialized for conduction.
Stems have several functions including supporting leaves, flowers, and fruits; transporting water and nutrients between roots and other plant parts; and storing food. They originate from the epicotyl region of seed embryos. Herbaceous stems are soft and green while woody stems are tough with secondary growth. Stems have internal specialized tissues like xylem and phloem that conduct water and nutrients respectively. Some stems are modified for storage, protection, or reproduction.
1. Shoot System
-Stem-
Prepared by:
Group III
BS Bio 1-C
2. Stems
The main body of the
portion above the
ground of the tree,
shrub, herb, or other
plant; the ascending
axis, whether above or
below the ground of a
plant, in contradiction
to the descending axis
or root.
3. MAJOR FUNCTIONS
OF STEMS
-Stems support
-Stems Conduct
-Stem produce new ling tissue
4. STEMS SUPPORT
Provides mechanical support and raise leaves into the
air, thus facilitating photosynthesis. Flowers and fruits
are also produced in position, for facilitating
pollination and seed dispersal.
STEMS CONDUCT
o Provides a pathway for movement of water and mineral
nutrients from roots to leaves and for transfer of foods ,
hormones and to other metabolites from one part to
another.
STEMS PRODUCE NEW LIVING TISSUE
o Provide new living tissue for normal metabolism of
plant.
6. A stem is an organ consisting of
An alternating system of nodes, the points at
which leaves are attached
Internodes, the stem segments between
nodes
7. An axillary bud is a structure that has the
potential to form a lateral shoot, or branch
An apical bud, or terminal bud, is located near
the shoot tip and causes elongation of a young
shoot
Apical dominance helps to maintain dormancy
in most non-apical buds
Lenticels are structure that permit the passage of
gas inward and outward.
Leaf scar are characteristic scar on stem axis
made by leaf abscission.
Bud scales are small modified leaves for
protection from desiccation.
8. Dormant shoot apex with its protective scales is a BUD.
Bud Scars are the scars left from the removal of bud.
Leaf primordium is an immature leaf of the
shoot.
Intercalary meristem the portion of the internodes
above the node . Made up of actively dividing cells
responsible for the elongation of the monocot stem.
9.
10. Apical bud
Fig. 35-12 Bud scale
Axillary buds
This year’s growth
(one year old) Leaf
scar
Bud Node
One-year-old side
scar branch formed
Internode from axillary bud
near shoot tip
Last year’s growth
(two years old) Leaf scar
Stem
Bud scar left by apical
bud scales of previous
winters
Growth of two
years ago
(three years old) Leaf scar
12. Shoot Apex
organization
The outer group
consisting of one or
more peripheral cell
layer is known as the
TUNICA. These cells
divide anticlinally
(perpendicular to the
surface of the shoot
apex)
The CORPUS lies
below the tunica and
initially has a single
layer of cells. Corpus
cells divide anticlinally
and periclinally
(parallel to the surface
of the shoot apex.)
13. A shoot apical meristem is a dome-
shaped mass of dividing cells at the shoot
tip
Leaves develop from leaf primordia
along the sides of the apical meristem
Axillary buds develop from
meristematic cells left at the bases of leaf
primordia
14. Fig. 35-16
Shoot apical meristem Leaf primordia
Young
leaf
Developing
vascular
strand
Axillary bud
meristems
0.25 mm
15. Primary Meristems
Protoderm- the outermost layer of cells.
It develops into epidermis--- the special
primary tissue that covers and protects all
underlying primary tissues. The epidermis
prevents excessive water loss and yet
allows for exchange of gases necessary for
respiration and photosynthesis.
16. Primary Meristems
Ground meristem- Comprises the
greater portion of meristematic tissue of
the shoot tip. Primary tissues forming
from the ground meristem are:
a) Pith- in the very center of stem
b) Cortex- in a cylinder just beneath the
epidermis and surrounding the vascular
tissues. Sometimes pith and cortex are
connected by pith rays.
17. Primary Meritsems
Procambium cells give rise to
primary vascular tissues
namely;
a) Primary phloem
b) Primary xylem
19. • Meristems are perpetually embryonic tissue and
allow for indeterminate growth
• Apical meristems are located at the tips of roots
and shoots and at the axillary buds of shoots
• Apical meristems elongate shoots and roots, a
process called primary growth
20. Stems undergo primary growth
which results in the formation of
primary tissues. These include the
Epidermis
Ground tissue
primary vascular tissues
(primary xylem and primary
phloem)
22. Summary of Primary Development
Protoderm Epidermis
Ground meristem Cortex
Apical Meristem Pith and pith
rays
Procambium Phloem
Vascular Cambium
Xylem
23. Primary Growth development
The term stele is applied to the part of the stem that includes
primary vascular tissues, pith, and pith rays. The primary plant
body is composed of the above primary tissues.
The main functions of these primary tissues may be
summarized as shown below.
Epidermis: Protects underlying tissues.
Vascular tissues
Phloem: Conducts Food
Vascular Cambium: produces secondary phloem and secondary
xylem
24. Xylem: conducts water and mineral salts , and gives
strength to stem.
Cortex: Stores food and in young stems, manufactures
food, strengthens and protects.
Pith: Stores food
Pith rays: Store food, and conduct water, mineral salts,
and food radically.
25. The young dicot stem
The stellar type exhibited by a dicot
stem is a EUSTELE.
The type of xylem maturation is
known as Endarch.
Secondary growth is present.
27. Fig. 35-17b
Ground
tissue
Epidermis
Key
to labels
Vascular
Dermal bundles
Ground
1 mm
Vascular (b) Cross section of stem with scattered vascular bundles
(typical of monocots)
28. The monocot stem
The vascular bundles are scattered
throughout the ground tissue. The type of
stele exhibit is ATACTOSTELE.
In most monocot stems, the vascular
bundles are scattered throughout the
ground tissue, rather than forming a ring.
They do not have secondary growth.
29. Fig. 35-17
Phloem Xylem
Sclerenchyma Ground
Ground tissue
(fiber cells) tissue
connecting
pith to cortex
Pith Epidermis
Key
to labels
Epidermis Cortex Vascular
Dermal bundles
Vascular
bundle Ground
1 mm Vascular 1 mm
(a) Cross section of stem with vascular bundles forming (b) Cross section of stem with scattered vascular bundles
a ring (typical of eudicots) (typical of monocots)
32. • Secondary growth occurs in stems and
roots of woody plants but rarely in leaves
• The secondary plant body consists of the
tissues produced by the vascular cambium
and cork cambium
• Secondary growth is characteristic of
gymnosperms and many eudicots, but not
monocots
34. Stem anatomy, secondary structure
These tissue layers form the Periderm.
The outermost layer is the phellem,
consisting of cork cells.
Immediately inner to it is the phellogen, or
the cork cambium, consisting of flattened
dividing cells.
The third layer is the pheloderm, few cell
layers in thickness.
35. Fig. 35-19a1
(a) Primary and secondary growth Pith
in a two-year-old stem Primary xylem
Vascular cambium
Epidermis Primary phloem
Cortex Cortex
Primary phloem Epidermis
Vascular cambium
Primary xylem
Pith
Periderm (mainly
cork cambia
and cork)
Secondary phloem
Secondary
xylem
36. Fig. 35-19a2
(a) Primary and secondary growth Pith
in a two-year-old stem Primary xylem
Vascular cambium
Epidermis Primary phloem
Cortex Cortex
Primary phloem Epidermis
Vascular cambium
Vascular ray
Primary xylem
Secondary xylem
Pith
Secondary phloem
First cork cambium
Cork
Periderm (mainly
cork cambia
and cork)
Secondary phloem
Secondary
xylem
37. Fig. 35-19a3
(a) Primary and secondary growth Pith
in a two-year-old stem Primary xylem
Vascular cambium
Epidermis Primary phloem
Cortex Cortex
Primary phloem Epidermis
Vascular cambium
Vascular ray
Primary xylem
Secondary xylem
Pith
Secondary phloem
First cork cambium
Cork
Periderm (mainly Most recent cork
cork cambia cambium
and cork)
Cork
Secondary phloem Bark
Layers of
periderm
Secondary
xylem
38. Fig. 35-19b
Secondary phloem Bark
Vascular cambium
Late wood Cork
Secondary xylem cambium Periderm
Early wood
Cork
0.5 mm
Vascular ray Growth ring
(b) Cross section of a three-year-
old Tilia (linden) stem (LM)
0.5 mm
39. The Vascular Cambium and Secondary
Vascular Tissue
The vascular cambium is a cylinder of meristematic
cells one cell layer thick
It develops from undifferentiated parenchyma cells
40. In cross section, the vascular cambium appears
as a ring of initials
The initials increase the vascular cambium’s
circumference and add secondary xylem to the
inside and secondary phloem to the outside
41. Secondary xylem accumulates as wood, and
consists of tracheids, vessel elements (only in
angiosperms), and fibers
Early wood, formed in the spring, has thin cell walls
to maximize water delivery
Late wood, formed in late summer, has thick-walled
cells and contributes more to stem support
In temperate regions, the vascular cambium of
perennials is dormant through the winter
42. Tree rings are visible where late and early
wood meet, and can be used to estimate a
tree’s age
Dendrochronology is the analysis of tree ring
growth patterns, and can be used to study
past climate change
43. As a tree or woody shrub ages, the older
layers of secondary xylem, the heartwood,
no longer transport water and minerals
The outer layers, known as sapwood, still
transport materials through the xylem
Older secondary phloem sloughs off and
does not accumulate
44. Fig. 35-22
Growth
ring
Vascular
ray
Heartwood
Secondary
xylem Sapwood
Vascular cambium
Secondary phloem
Bark
Layers of periderm
45. The Cork Cambium and the
Production of Periderm
The cork cambium gives rise to the secondary
plant body’s protective covering, or periderm
Periderm consists of the cork cambium plus the
layers of cork cells it produces
Bark consists of all the tissues external to the
vascular cambium, including secondary phloem
and periderm
Lenticels in the periderm allow for gas
exchange between living stem or root cells and
the outside air
46. A plant can grow throughout its life; this is
called indeterminate growth
Some plant organs cease to grow at a certain
size; this is called determinate growth
Annuals complete their life cycle in a year
or less
Biennials require two growing seasons
Perennials live for many years
49. Monocot vs.Dicot
Parameter Monocot Dicot
Extent of cortex No distinct cortex Cortex found at the
outer part of ground
tissue
Presence or absence of Absent Present
pith
Type of stele Atactostele Eustele
Presence or absence of Absent Present
vascular cambium
50. Modified Stem
Modification of the stem would depend on
the need of the plant to survive…
… like the animals it learns how to
adapt.
51. Bulb – consist of small amount
of vertical stem and a massive
quantity of thick, fleshy storage
leaves.
- most of them consist of
concentric rings of scales
attached to a basal plate.
.
62. Aerial MODIFICATIONS OF STEM
•TENDRILS
IN grapes
Axillary bud is modified
into tendrils.
•CLADOPHYLL /
PHYLLOCLADE
The entire shoot is
flattend & leaf like.
63. References
• Campbell, N.A., J.B Reece and L.G. Mitchell.
1999. Biology. 5th ed. USA: The
Benjamin/Cummings Publishing Co. Inc.
• Weier, E.T., R.C Stocking., M. G Barbour and Rost
T. L.1982. Botany an Introduction to Plant
Biology. 6th ed. USA: John Willey and Sons Inc.