The document discusses vascular tissue in plants. It notes that vascular tissue is complex conducting tissue composed of xylem and phloem, which transport fluids and nutrients internally. Vascular bundles contain xylem and phloem as well as supporting cells. Xylem typically lies closer to the interior of stems while phloem is nearer the exterior, transporting sugars. There are four patterns of primary xylem development - centrarch, exarch, endarch and mesarch - depending on whether development proceeds from the center outward, outside inward, inside outward, or from the middle in both directions.
Sapwood:
“When a tree is young, certain cells within the wood are alive and capable of conducting sap or storing nutrients, and the wood is referred to as sapwood. The sapwood also termed as Alebernum.”
Heartwood:
“Heartwood also called duramen. Dead central wood of trees. As new sapwood is formed under the bark, the inner sap wood changes to heartwood. In the wood under going this change the living cells die.”
Sapwood is new wood and is like a pipeline which moves water through the tree up to the leaves.
The sapwood is lighted colored and formed of living cells associated with vessels and fibers.
Sapwood commonly ranges from 4 to 6 cm (1-1/2 to 2 in.) in radial thickness.
Many second-growth trees of merchantable size consist mostly of sapwood.
Heartwood consists of inactive cells that do not function in either water conduction or food storage.
The compounds (including resins, phenols, and terpenes, sometimes referred to as extractives) not only help make heartwood more resistant to attack by insects and decay organisms but also tend to give this inner portion of the stem a distinctive darker color.
The proportion of heartwood to sapwood in the main stem does vary with species. Black locust, for example, usually has a very narrow band – often less than an inch – of functioning sapwood, whereas maple stems often can have many inches of sapwood and relatively narrow cores of heartwood.
Sapwood is formed due to the cambial activity of the secondary xylem.
Heartwood is formed due to accumulation of different compounds, such as oils gums, and resins, etc.
The oils, resins and colouring materials infiltrate the walls, and gums and resins may fill the lumina of the cells in heart wood.
During the transformation a number of changes occur – all living cells lose protoplasts; water contents of cell walls are reduced; food materials are withdrawn from the living cells; tyloses are frequently formed which block the vessels, the parenchyma walls become lignified; oils, gums, tannins, resins and other substances develop in the cells.
Sapwood performs the physiological activities, such as conduction of water and nutrients, storage of food, etc.
The function of heartwood is no longer of conduction, it gives only mechanical support to the stem.
The heartwood part of a tree is also far more susceptible to fungus than the centre of the trunk.
Heartwood contains far less moisture than sapwood and will have far less shrinkage when it’s dried.
The sapwood in the centre of the tree dies, forming heartwood, and as the cells die they release chemicals that change the colour of the wood, as well as making the wood stronger and more resistant to attack by insects.
This pdf contains information about the various methods of documentation in plant taxonomy. It includes, floras, manuals, monographs, dictionaries, glosaries, indexes, icones, etc.
Sapwood:
“When a tree is young, certain cells within the wood are alive and capable of conducting sap or storing nutrients, and the wood is referred to as sapwood. The sapwood also termed as Alebernum.”
Heartwood:
“Heartwood also called duramen. Dead central wood of trees. As new sapwood is formed under the bark, the inner sap wood changes to heartwood. In the wood under going this change the living cells die.”
Sapwood is new wood and is like a pipeline which moves water through the tree up to the leaves.
The sapwood is lighted colored and formed of living cells associated with vessels and fibers.
Sapwood commonly ranges from 4 to 6 cm (1-1/2 to 2 in.) in radial thickness.
Many second-growth trees of merchantable size consist mostly of sapwood.
Heartwood consists of inactive cells that do not function in either water conduction or food storage.
The compounds (including resins, phenols, and terpenes, sometimes referred to as extractives) not only help make heartwood more resistant to attack by insects and decay organisms but also tend to give this inner portion of the stem a distinctive darker color.
The proportion of heartwood to sapwood in the main stem does vary with species. Black locust, for example, usually has a very narrow band – often less than an inch – of functioning sapwood, whereas maple stems often can have many inches of sapwood and relatively narrow cores of heartwood.
Sapwood is formed due to the cambial activity of the secondary xylem.
Heartwood is formed due to accumulation of different compounds, such as oils gums, and resins, etc.
The oils, resins and colouring materials infiltrate the walls, and gums and resins may fill the lumina of the cells in heart wood.
During the transformation a number of changes occur – all living cells lose protoplasts; water contents of cell walls are reduced; food materials are withdrawn from the living cells; tyloses are frequently formed which block the vessels, the parenchyma walls become lignified; oils, gums, tannins, resins and other substances develop in the cells.
Sapwood performs the physiological activities, such as conduction of water and nutrients, storage of food, etc.
The function of heartwood is no longer of conduction, it gives only mechanical support to the stem.
The heartwood part of a tree is also far more susceptible to fungus than the centre of the trunk.
Heartwood contains far less moisture than sapwood and will have far less shrinkage when it’s dried.
The sapwood in the centre of the tree dies, forming heartwood, and as the cells die they release chemicals that change the colour of the wood, as well as making the wood stronger and more resistant to attack by insects.
This pdf contains information about the various methods of documentation in plant taxonomy. It includes, floras, manuals, monographs, dictionaries, glosaries, indexes, icones, etc.
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
Honest Reviews of Tim Han LMA Course Program.pptxtimhan337
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The Roman Empire A Historical Colossus.pdfkaushalkr1407
The Roman Empire, a vast and enduring power, stands as one of history's most remarkable civilizations, leaving an indelible imprint on the world. It emerged from the Roman Republic, transitioning into an imperial powerhouse under the leadership of Augustus Caesar in 27 BCE. This transformation marked the beginning of an era defined by unprecedented territorial expansion, architectural marvels, and profound cultural influence.
The empire's roots lie in the city of Rome, founded, according to legend, by Romulus in 753 BCE. Over centuries, Rome evolved from a small settlement to a formidable republic, characterized by a complex political system with elected officials and checks on power. However, internal strife, class conflicts, and military ambitions paved the way for the end of the Republic. Julius Caesar’s dictatorship and subsequent assassination in 44 BCE created a power vacuum, leading to a civil war. Octavian, later Augustus, emerged victorious, heralding the Roman Empire’s birth.
Under Augustus, the empire experienced the Pax Romana, a 200-year period of relative peace and stability. Augustus reformed the military, established efficient administrative systems, and initiated grand construction projects. The empire's borders expanded, encompassing territories from Britain to Egypt and from Spain to the Euphrates. Roman legions, renowned for their discipline and engineering prowess, secured and maintained these vast territories, building roads, fortifications, and cities that facilitated control and integration.
The Roman Empire’s society was hierarchical, with a rigid class system. At the top were the patricians, wealthy elites who held significant political power. Below them were the plebeians, free citizens with limited political influence, and the vast numbers of slaves who formed the backbone of the economy. The family unit was central, governed by the paterfamilias, the male head who held absolute authority.
Culturally, the Romans were eclectic, absorbing and adapting elements from the civilizations they encountered, particularly the Greeks. Roman art, literature, and philosophy reflected this synthesis, creating a rich cultural tapestry. Latin, the Roman language, became the lingua franca of the Western world, influencing numerous modern languages.
Roman architecture and engineering achievements were monumental. They perfected the arch, vault, and dome, constructing enduring structures like the Colosseum, Pantheon, and aqueducts. These engineering marvels not only showcased Roman ingenuity but also served practical purposes, from public entertainment to water supply.
Embracing GenAI - A Strategic ImperativePeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
Instructions for Submissions thorugh G- Classroom.pptxJheel Barad
This presentation provides a briefing on how to upload submissions and documents in Google Classroom. It was prepared as part of an orientation for new Sainik School in-service teacher trainees. As a training officer, my goal is to ensure that you are comfortable and proficient with this essential tool for managing assignments and fostering student engagement.
Francesca Gottschalk - How can education support child empowerment.pptxEduSkills OECD
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Acetabularia acetabulum is a single-celled green alga that in its vegetative state is morphologically differentiated into a basal rhizoid and an axially elongated stalk, which bears whorls of branching hairs. The single diploid nucleus resides in the rhizoid.
Read| The latest issue of The Challenger is here! We are thrilled to announce that our school paper has qualified for the NATIONAL SCHOOLS PRESS CONFERENCE (NSPC) 2024. Thank you for your unwavering support and trust. Dive into the stories that made us stand out!
2. Vascular tissue is a complex conducting tissue, formed of more than one cell type
The primary components of vascular tissue are the xylem and phloem. These two tissues transport
fluid and nutrients internally.
There are also two meristems associated with vascular tissue: the vascular cambium and the cork
cambium. All the vascular tissues within a particular plant together constitute the vascular tissue
system of that plant.
The cells in vascular tissue are typically long and slender. Since the xylem and phloem function in
the conduction of water, minerals, and nutrients throughout the plant, it is not surprising that their
form should be similar to pipes. The individual cells of phloem are connected end-to-end, just as the
sections of a pipe.
The new tissue is aligned with existing vascular tissue, maintaining its connection throughout the
plant.
The vascular tissue in plants is arranged in long, discrete strands called vascular bundles. These
bundles include xylem and phloem, as well as supporting and protective cells
3. • In the plant kingdom, the earliest examples of an organized vascular system are encountered among the
brown algae, which possess phloem with no xylem.
• The water-conducting system evolved much later; its adaptation and refinement became mandatory for
the development of plants on land, because the lignified conducting and supporting cells in the xylem
provide the long-distance water conduction and the mechanical support needed in a terrestrial habitat.
4. Location of xylem and phloem
In stems and roots, the xylem typically lies closer to the interior of the stem with phloem towards the
exterior of the stem.
In the stems of some Asteridae dicots, there may be phloem located inwardly from the xylem.
In leaves, the vascular bundles are located among the spongy mesophyll. The xylem is oriented toward
the adaxial surface of the leaf (usually the upper side), and phloem is oriented toward the abaxial surface of
the leaf (usually the underside).
The main reason behind aphids are typically found on the underside of the leaves rather than on the upper,
is the phloem transports sugars manufactured by the leaves , transport of food in the form of sugar through
phloem and they are closer to the lower surface
5. Location of phloem towards the exterior of stem or root
and xylem towards interior of stem
Location of phloem towards the abaxial surface of leaf and
xylem towards adaxial surface of leaf
6. Primary and Secondary Xylem
• Primary xylem is the xylem that formed during primary growth of procambium.
It includes protoxylem and metaxylem. Metaxylem develops after the protoxylem but before secondary
xylem. Metaxylem has wider vessels and tracheids than protoxylem.
• Secondary xylem is the xylem that is formed during secondary growth of vascular cambium.
Although secondary xylem is also found in members of the "Gymnosperm" groups Gnetophyta and
Ginkgophyta and to a lesser extent in members of the Cycadophyta, the two main groups in which
secondary xylem can be found are:
7. Conifers (Coniferae): there are some six hundred species of conifers. All species have secondary xylem,
which is relatively uniform in structure throughout this group. Many conifers become tall trees: the secondary
xylem of such trees is used and marketed as soft wood.
Angiosperms: there are some quarters of a million to four hundred thousand species of Angiosperms. Within
this group secondary xylem is rare in the monocots. Many monocot Angiosperms become trees, and the
secondary xylem of these is used and marketed as hard wood.
8. Protoxylem and metaxylem
• As a young vascular plant grows, one or more strands of
primary xylem form in its stems and roots.
• The first xylem to develop is called 'protoxylem'. In appearance
protoxylem is usually distinguished by narrower vessels
formed of smaller cells.
• Some of these cells have walls which contain thickenings in the
form of rings or helices.
9. • Functionally, protoxylem can extend: the cells are able to grow in
size and develop while a stem or root is elongating. Later,
'metaxylem' develops in the strands of xylem.
• Metaxylem vessels and cells are usually larger; the cells have
thickenings which are typically either in the form of ladder like
transverse bars (scalariform) or continuous sheets except for
holes or pits (pitted). Functionally, metaxylem completes its
development after elongation ceases when the cells no longer
need to grow in size.
10. Patterns of protoxylem and metaxylem
There are four main patterns to the arrangement of protoxylem and metaxylem in
stems and roots
Centrarch refers to the case in which the primary xylem forms a single cylinder in the
center of the stem and develops from the center outwards.
The protoxylem is thus found in the central core and the metaxylem in a cylinder
around it.
This pattern was common in early land plants, such as "Rhyniophytes", but is not
present in any living plants.
11. Exarch is used when there is more than one strand of primary xylem in a stem or
root, and the xylem develops from the outside towards the center, i.e., centripetally.
The metaxylem is thus closest to the center of the stem or root and the protoxylem
closest to the periphery.
The roots of vascular plants are normally considered to have exarch development.
Endarch is used when there is more than one strand of primary xylem in a stem or
root, and the xylem develops from the inside towards the periphery, i.e.,
centrifugally.
The protoxylem is thus closest to the center of the stem or root and the metaxylem
closest to the periphery.
The stems of seed plants typically have endarch development.
13. Mesarch is used when there is more than one strand of primary xylem
in a stem or root, and the xylem develops from the middle of a strand
in both directions.
The metaxylem is thus on both the peripheral and central sides of the
strand with the protoxylem between the metaxylem (possibly
surrounded by it).
The leaves and stems of many ferns have mesarch development.