1. Gymnosperms are naked seeded non-flowering plants that show alternation of generations between sporophyte and gametophyte stages. The sporophyte plant body is well differentiated into roots, stems, and leaves while the gametophyte is greatly reduced.
2. Gymnosperms reproduce sexually through cones that contain either microsporangia or megasporangia. Pollination occurs and pollen tubes carry sperm to fertilize eggs within the ovules, forming seeds with embryos.
3. The life cycle involves microspores forming male gametophytes that produce sperm, and megaspores forming reduced female gametophytes containing eggs. Fertilization occurs
Pteridophytes are vascular plants and have leaves (known as fronds), roots and sometimes true stems, and tree ferns have full trunks. Examples include ferns, horsetails and club-mosses. Fronds in the largest species of ferns can reach some six metres in length!
Many ferns from tropical rain forests are epiphytes, which means they only grow on other plant species; their water comes from the damp air or from rainfall running down branches and tree trunks. There are also some purely aquatic ferns such as water fern or water velvet (Salvinia molesta) and mosquito ferns (Azolla species).
Pteridophytes do not have seeds or flowers either, instead they also reproduce via spores.
There are around 13,000 species of Pteridophytes.
Gymnosperm is from the Greek “gymnos” naked, and “sperma” seeds. They are groups of vascular plants that reproduce by means of an exposed seeds or ovules. They are phanerogams according to A. W. Eichler.
Pteridophytes are vascular plants and have leaves (known as fronds), roots and sometimes true stems, and tree ferns have full trunks. Examples include ferns, horsetails and club-mosses. Fronds in the largest species of ferns can reach some six metres in length!
Many ferns from tropical rain forests are epiphytes, which means they only grow on other plant species; their water comes from the damp air or from rainfall running down branches and tree trunks. There are also some purely aquatic ferns such as water fern or water velvet (Salvinia molesta) and mosquito ferns (Azolla species).
Pteridophytes do not have seeds or flowers either, instead they also reproduce via spores.
There are around 13,000 species of Pteridophytes.
Gymnosperm is from the Greek “gymnos” naked, and “sperma” seeds. They are groups of vascular plants that reproduce by means of an exposed seeds or ovules. They are phanerogams according to A. W. Eichler.
Pollen pistil interaction
Types of Incompatibility in plants
Methods to overcome Incompatibility
Prepared by
Dr. T. Annie Sheron
Assistant Professor of Botany
DEPARTMENT OF BOTANY
KAKATIYA GOVERNMENT COLLEGE, HANAMKONDA
This is a detailed presentation on Morphology, anatomy and reproduction of Marchantia spp. with high quality pics and eye capturing transitions and animations
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).
Pollen pistil interaction
Types of Incompatibility in plants
Methods to overcome Incompatibility
Prepared by
Dr. T. Annie Sheron
Assistant Professor of Botany
DEPARTMENT OF BOTANY
KAKATIYA GOVERNMENT COLLEGE, HANAMKONDA
This is a detailed presentation on Morphology, anatomy and reproduction of Marchantia spp. with high quality pics and eye capturing transitions and animations
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).
Class 12||Chapter 2|| Sexual Reproduction in flowering plantsPrathamBiology
This chapter includes flowers, their detailed structure and developmental processess which took place durin sexual reproduction. Helpful for Board and NEET students.
Fell free for any query or suggestion
Mail us on: biologypratham@gmail.com
Website : www.prathambiology.in
2- Sketch the life cycle of a conifer- Include all relevant terms from.pdfKeithemtPeaked
2. Sketch the life cycle of a conifer. Include all relevant terms from p.10 of this chapter. One
characteristic of Pinophytes (and many other non-flowering plants) worthy of note is their cones
(which are actually strobili, the same structure observed in vascular non-seed plants like club
mosses and horsetails). Non-flowering seed plants typically produce both male and female cones
(the plants may either be monoecious or dioecious, depending on the lineage). Both male and
female cones are formed of many scales (leaf-like structures) surrounding a central axis (the
stem-like structure the scales emerge from); microsporangia or megasporangia are found at the
base of the scales. The male cones contain numerous microsporangia that produce haploid
microspores (there are typically hundreds of microspores produced per microsporangium; a
microsporangium typically ends up looking like a large hollow sac containing hundreds of tiny
free-floating microspores). These microspores grow into small (four-celled) microgametophytes;
when the microgametophytes are mature they are called pollen grains. Female cones have ovules
in them; each ovule contains a megasporangium surrounded by integument. The ovules of the
female cones are typically found at the base of the cone's scales (which are typically much larger
and stronger than the scales of male cones). The megasporangium produces megaspores that
grow into megagametophytes. Each megagametophyte houses at least one archegonium, which
develops an egg that is fertilized by the sperm from a pollen grain. The fertilized egg becomes a
zygote, which eventually develops into a embryo (that is diploid) surrounded by the tissue of the
meqagametophyte develops into a embryo (that is diploid) surrounded by the tissue of the
megagametophyte (which develops into haploid nutritive tissue) and the megasporangium
(which develops into the seed coat). A mature seed is composed of a seed coat surrounding
nutritive tissue and the embryo; gymnosperm seeds do not have endosperm, and are not
contained in a fruit. The seeds are released into the environment, where they can germinate and
grow into a sporophyte plant..
Kingdom Plantae presented by Vrushali Gharat to Mr. Kailash vilegaveKailash Vilegave
Classification Of Kingdom Plantae, Classification Of Kingdom Plantae, Economic importance Algae.
Ulothrix
Reproduction
Mosses and Liverwort
life cycle of all plants.
Gnetum: A Powerpoint Presentation on Gymnospemsshivduraigaran
The Gymnosperms are a group of seed-producing plants (spermatophytes) that includes conifers (Pinophyta), cycads, Ginkgo, and gnetophytes. The term "gymnosperm" comes from the Greek composite word γυμνόσπερμος (γυμνός gymnos, "naked" and σπέρμα sperma, "seed"), meaning "naked seeds". The name is based on the unenclosed condition of their seeds (called ovules in their unfertilized state). The non-encased condition of their seeds stands in contrast to the seeds and ovules of flowering plants (angiosperms), which are enclosed within an ovary. Gymnosperm seeds develop either on the surface of scales or leaves, which are often modified to form cones, or solitary as in Yew, Torreya, Ginkgo.
The gymnosperms and angiosperms together compose the spermatophytes or seed plants. The gymnosperms are divided into six phyla. Organisms that belong to the Cycadophyta, Ginkgophyta, Gnetophyta, and Pinophyta (also known as Coniferophyta) phyla are still in existence while those in the Pteridospermales and Cordaitales phyla are now extinct.
By far the largest group of living gymnosperms are the conifers (pines, cypresses, and relatives), followed by cycads, gnetophytes (Gnetum, Ephedra and Welwitschia), and Ginkgo biloba (a single living species). Roots in some genera have fungal association with roots in the form of micorrhiza(Pinus), while in some others(Cycas) small specialised roots called coralloid roots are associated with nitrogen fixing cyanobacteria.
Gnetum is a genus of gymnosperms, the sole genus in the family Gnetaceae and order Gnetales. They are tropical evergreen trees, shrubs and lianas. Unlike other gymnosperms, they possess vessel elements in the xylem. Some species have been proposed to have been the first plants to be insect-pollinated as their fossils occur in association with extinct pollinating scorpion flies. Molecular phylogenies based on nuclear and plastid sequences from most of the species indicate hybridization among some of the Southeast Asian species. Fossil-calibrated molecular-clocks suggest that the Gnetum lineages now found in Africa, South America and Southeast Asia are the result of ancient long-distance dispersal across seawater
Richard's aventures in two entangled wonderlandsRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
Nutraceutical market, scope and growth: Herbal drug technologyLokesh Patil
As consumer awareness of health and wellness rises, the nutraceutical market—which includes goods like functional meals, drinks, and dietary supplements that provide health advantages beyond basic nutrition—is growing significantly. As healthcare expenses rise, the population ages, and people want natural and preventative health solutions more and more, this industry is increasing quickly. Further driving market expansion are product formulation innovations and the use of cutting-edge technology for customized nutrition. With its worldwide reach, the nutraceutical industry is expected to keep growing and provide significant chances for research and investment in a number of categories, including vitamins, minerals, probiotics, and herbal supplements.
Multi-source connectivity as the driver of solar wind variability in the heli...Sérgio Sacani
The ambient solar wind that flls the heliosphere originates from multiple
sources in the solar corona and is highly structured. It is often described
as high-speed, relatively homogeneous, plasma streams from coronal
holes and slow-speed, highly variable, streams whose source regions are
under debate. A key goal of ESA/NASA’s Solar Orbiter mission is to identify
solar wind sources and understand what drives the complexity seen in the
heliosphere. By combining magnetic feld modelling and spectroscopic
techniques with high-resolution observations and measurements, we show
that the solar wind variability detected in situ by Solar Orbiter in March
2022 is driven by spatio-temporal changes in the magnetic connectivity to
multiple sources in the solar atmosphere. The magnetic feld footpoints
connected to the spacecraft moved from the boundaries of a coronal hole
to one active region (12961) and then across to another region (12957). This
is refected in the in situ measurements, which show the transition from fast
to highly Alfvénic then to slow solar wind that is disrupted by the arrival of
a coronal mass ejection. Our results describe solar wind variability at 0.5 au
but are applicable to near-Earth observatories.
Seminar of U.V. Spectroscopy by SAMIR PANDASAMIR PANDA
Spectroscopy is a branch of science dealing the study of interaction of electromagnetic radiation with matter.
Ultraviolet-visible spectroscopy refers to absorption spectroscopy or reflect spectroscopy in the UV-VIS spectral region.
Ultraviolet-visible spectroscopy is an analytical method that can measure the amount of light received by the analyte.
Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
Monitor common gases, weather parameters, particulates.
This presentation explores a brief idea about the structural and functional attributes of nucleotides, the structure and function of genetic materials along with the impact of UV rays and pH upon them.
Richard's entangled aventures in wonderlandRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
Comparing Evolved Extractive Text Summary Scores of Bidirectional Encoder Rep...University of Maribor
Slides from:
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Track: Artificial Intelligence
https://www.etran.rs/2024/en/home-english/
Deep Behavioral Phenotyping in Systems Neuroscience for Functional Atlasing a...Ana Luísa Pinho
Functional Magnetic Resonance Imaging (fMRI) provides means to characterize brain activations in response to behavior. However, cognitive neuroscience has been limited to group-level effects referring to the performance of specific tasks. To obtain the functional profile of elementary cognitive mechanisms, the combination of brain responses to many tasks is required. Yet, to date, both structural atlases and parcellation-based activations do not fully account for cognitive function and still present several limitations. Further, they do not adapt overall to individual characteristics. In this talk, I will give an account of deep-behavioral phenotyping strategies, namely data-driven methods in large task-fMRI datasets, to optimize functional brain-data collection and improve inference of effects-of-interest related to mental processes. Key to this approach is the employment of fast multi-functional paradigms rich on features that can be well parametrized and, consequently, facilitate the creation of psycho-physiological constructs to be modelled with imaging data. Particular emphasis will be given to music stimuli when studying high-order cognitive mechanisms, due to their ecological nature and quality to enable complex behavior compounded by discrete entities. I will also discuss how deep-behavioral phenotyping and individualized models applied to neuroimaging data can better account for the subject-specific organization of domain-general cognitive systems in the human brain. Finally, the accumulation of functional brain signatures brings the possibility to clarify relationships among tasks and create a univocal link between brain systems and mental functions through: (1) the development of ontologies proposing an organization of cognitive processes; and (2) brain-network taxonomies describing functional specialization. To this end, tools to improve commensurability in cognitive science are necessary, such as public repositories, ontology-based platforms and automated meta-analysis tools. I will thus discuss some brain-atlasing resources currently under development, and their applicability in cognitive as well as clinical neuroscience.
Mammalian Pineal Body Structure and Also Functions
Life cycle of gymnosperms
1. LIFE CYCLE OF GYMNOSPERMS
Gymnosperm Definition:
Naked seeded non-flowering plants are called gymnosperms.
LIFE CYCLE:
Gymnosperm shows a clear alternation of sporophytic and gametophytic generations. The Plant
body is sporophytic generation.The gametophytic is very much reduced. It had completely lost
independent existence.
2. SPOROPHYTE (VEGETATIVE PLANT):
The plant body is a sporophyte. It is well differentiated into roots, stem and leaves.
1. Roots:
Primary or tap root is well developed. Root develops root caps. Corraloid Roots and mycorrhizal
Roots are found in some genera. Roots provided mechanical support to plants. Roots also absorb
water and minerals for plants.
2. Leaves:
Leaves of two types:
a) Microphyllous or scale leaves:
These are sac like leaves.These are much smaller in size.These are found in Ephedra. Scale
leaves are associated with the foliage leaves other plants.
b) Megaphyllous or foliage leaves:
These are large and well developed leaves. Both simple and compound leaves are found. The
foliage leaves are without a reticulate venation. The branching of the veins is dichotomous type.
There leaves are modified to withstand the xerophytic conditions. These leaves have tough
cuticle, sunken stomata mesarch bundle. These are found in Cycas and Pinus. Leaves of Cycas
may reach the length of six feet.
3. Stem:
The stem is woody. Vascular bundles are collateral(arrange in rings) and open. They are arrange
in ring in the primary stem. Secondary growth takes place by the activity of the cambium. It
produces the Secondary Xylem(woody). Xylem is formed onf Xylem parenchyma and tracheid.
3. They have no true vessels except the order Gnetales companion cells. Primary cambium may
remain active throughout the life of the plant. The secondary and tertiary cambia are found. It
produces alternate zones of wood. The activity of phellogen produces bark on the surface.
Secondary Growth:
Secondary growth occurs in gymnosperms. The girth of plants is increased during secondary
growth.Vascular cambium is involved in secondary growth. Secondary growth produces
Secondary wood. It produces secondary Xylem. Secondary growth produces distinct annual
rings. The plants having active secondary growths have reduced pith and cortex.
Reproduction:
Gymnosperms reproduce by seed formation. Vegetative reproduction is absent in gymnosperms.
Only Cycas reproduce vegetatively by formation of bulbil like structure
Cones or Strobili:
Gymnosperms are heterosporous. They produce micro and megaspore. They develop definite
unisexual cones or strobili. There are two types of strobili or cones.
1. Male cone
2. Female cone
Male cones are usually smaller in size than the female cones.
These cones show a great variation.
a) Male cone:
The male cones are smaller in size. They are produced in clusters on an axis(stem). Males cone
contains many microsporangia. These microsporangia produce many microspores by meiosis.
The microspores germinates within its own wall to form a small inconspicuous male
gametophyte.
b) Female cone:
4. The female cone has large size and they are more conspicuous. The female cone contains many
microsporangia. Each female cone is composed of a large number of scales called
megasporophylls. These megasporophylls are spirally arranged an woody in texture. An ovule is
present at base of each scale. Ovule is a megasporangium.
Sporangia:
(a) Microspore and Microsporangia:
Microspores (pollen grains) are produced in Microsporangia(anthers). They are borne on
microsporophyll (stamens). Microsporophylls are spirally arranged on the central axis of thje
male cone. Microsporangia have Microspore mother cells. Each cells divided by meiosis to form
four haploid microspores. Microspores are dispressed by wind.
(b) Megaspores and Megasporangia :
The Megaspores(embryo sac) are produced in megasporangia(ovules). They are borne on the
megasporophylls(carpels). The ovules are covered by a single integument. It has single
megaspore mother cell. This cell divides meiotically to form four megaspores. These megaspores
degenerate only one remains functional.
5. Gametophytes:
Male Gametophyte:
Microspore represents the beginning of the gametophytic stage. It germinates to give rise to male
prothallus within the spore wall. It has only one prothalial cells. It cuts of generative cells. This
generative cell represents the reduced antheridium. Generative cell divides into a basal stalk cell
and a body cell. Body cell gives rise to two male gametes. Pollen tube carries these two male
gametes (pollen grain) to the oosphere. Male gametes are non-motile except certain primitive
forms as Cycads.
Female Gametophyte:
The functional megaspore is the beginning of the gametophytic stage. It germinates to form
multicellular female peothallus within the spore wall. Superficial cells gives to rise to two or
simple archegonia towards the micropylar end. Each archegonia has a simple neck cells and a
venter. The venter contains an egg (oosphere) and a venter canal cell.
Pollination:
Pollination is the transfer of pollan grain from male cone to micropylar end of the ovule on
female cone. It occurs by wind. In some cases, it may occur in animals. A sticky fluid exudes
from the micropyle of the ovule. It is called pollination drop. The microscope wall adheres to
this drop of fluid. The liquid become dry. It pulls the male gametophyte down into the ovule.
After that micropyle is closed.
6. Formation of Pollen Tubes and Fertilization:
In some primitive gymnosperms, well developed pollen chambers are present at the fee apical
end of the nucellus. These chambers contains liquid. Flagellated sperms swim in it and reach the
egg. These pollen chambers are found in Ginkgo Cycas and Ephedra. Such chambers are absent
in other gymnosperms like pinus. In hese plants, pollen comes in direct contact with the surface
of the nucellar beak by pollination.
Male gametophyte produce a pollen tube. It is the extension of the inner wall (exine) of pollen. It
grows down into the nucellar tissue. It enters the archegonium and releases the non-motile
sperms directly into it. The basal end of the pollen tube bursts at the time of Fertilization. It
liberates the two flagellated sperms above the female gametophyte. One or both sperms may
enter an archegonium.Only sperm fertilize the egg.
Formation of Embryo and Seed:
Oospore is the beginning of gametophyte generation. The oospore gives rise to embryo. Embryo
formation is the most important characteristics of gymnosperms. It leads to formation of the
seed. Wall formation starts after the nuclear division. Then the embryo becomes cellular. The
embryo differentiates into the suspensor radical, hypocotyls, plumule, and cotyledons. Prothalial
tissues provide nourishment to developing embryo. Integument is transformed into the seed coat.
The unutilized prothalial cell becomes endosperm.
7. Polyembryony:
Formationn of several embryos in a single gametophyte is called Polyembryony. It is common
in gymnosperms. In this case, more than one archegonium are formed. Their eggs are fertilized
by sperm. Thus several zygotes are produced. It produces several embryos. Cleavages
Polyembryony is characteristics of a majority of conifers. In this case, certain embryo becomes
separated from one another. They give rise to a system of four or more distinct embryos.
Competition starts between the various embryos. It eliminates all embryos except one. The
surviving embryo grows and develops into seed.