Plant Development I: Tissue differentiation and function | Biology
And each pillar consists of Heavenly Stem, Earthly Branch and Hidden Stem as outlook, matters, events and relationships that are obvious. The quality of each Stem, its propensity for alchemical transformation and its relationships with other Stems and Branches provides extraordinary In order to help advanced practitioners connect to the spirit of the GanZhi, we will share ten . The theory of Stems and Branches tries to explain time as a quality of QI/energy. of space and time, which impacts its relationship with other objects in space. The understanding of the “deep energy” can help us to understand different.
They are alive at functional maturity, but lack a nucleus, ribosomes, or other cellular structures. Sieve cells are thus supported by companion cells, which lie adjacent to the sieve cells and provide metabolic support and regulation. The xylem and phloem always lie adjacent to each other. In stems, the xylem and the phloem form a structure called a vascular bundle; in roots, this is termed the vascular stele or vascular cylinder.
This light micrograph shows a cross section of a squash Curcurbita maxima stem. Each teardrop-shaped vascular bundle consists of large xylem vessels toward the inside and smaller phloem cells toward the outside. Xylem cells, which transport water and nutrients from the roots to the rest of the plant, are dead at functional maturity. Phloem cells, which transport sugars and other organic compounds from photosynthetic tissue to the rest of the plant, are living.
Chinese Heavenly Stems and Earthly Branches, Ten Stems and Twelve Branches
The vascular bundles are encased in ground tissue and surrounded by dermal tissue. Parenchyma are the most abundant and versatile cell type in plants. They have primary cell walls which are thin and flexible, and most lack a secondary cell wall. Parenchyma cells are totipotent, meaning they can divide and differentiate into all cell types of the plant, and are the cells responsible for rooting a cut stem. Most of the tissue in leaves is comprised of parenchyma cells, which are the sites of photosynthesis.
Leaves typically contains two types of parenchyma cells: The palisade parenchyma also called the palisade mesophyll has column-shaped, tightly packed cells.
Below the palisade parenchyma are the cells of the spongy parenchyma or spongy mesophyllwhich are loosely arranged with air spaces that all gaseous exchange between the leaf and the outside atmosphere.
Both of these types of parenchyma cells contain large quantities of chloroplasts for phytosynthesis. Parenchyma can also be associated with phloem cells in vascular tissue as parenchyma rays. They are long and thin cells that retain the ability to stretch and elongate; this feature helps them provide structural support in growing regions of the shoot system.
They are highly abundant in elongating stems. Schelrenchyma cells therefore cannot stretch, and they provide important structural support in mature stems after growth has ceased. Interestingly, schlerenchyma cells are dead at functional maturity. There are two types of sclerenchyma cells: Fibers are long, slender cells; sclereids are smaller-sized. Sclereids give pears their gritty texture, and are also part of apple cores.
We use sclerenchyma fibers to make linen and rope. A cross section of a leaf showing the phloem, xylem, sclerenchyma and collenchyma, and mesophyll. There are also some differences in how these tissues are arranged between monocots and dicots, as illustrated below: In dicot roots, the xylem and phloem of the stele are arranged alternately in an X shape, whereas in monocot roots, the vascular tissue is arranged in a ring around the pith. In addition, monocots tend to have fibrous roots while eudicots tend to have a tap root both illustrated above.
In left typical dicots, the vascular tissue forms an X shape in the center of the root. In right typical monocots, the phloem cells and the larger xylem cells form a characteristic ring around the central pith. The cross section of a dicot root has an X-shaped structure at its center.
The X is made up of many xylem cells. Phloem cells fill the space between the X. A ring of cells called the pericycle surrounds the xylem and phloem. The outer edge of the pericycle is called the endodermis. A thick layer of cortex tissue surrounds the pericycle.
The cortex is enclosed in a layer of cells called the epidermis. The monocot root is similar to a dicot root, but the center of the root is filled with pith. The phloem cells form a ring around the pith. Round clusters of xylem cells are embedded in the phloem, symmetrically arranged around the central pith.
- The Stems, The Branches and The Hidden Stems
- Introduction to the "STEMS AND BRANCHES" theory
- Ten Heavenly Stems and Twelve Earthly Branches
The outer pericycle, endodermis, cortex and epidermis are the same in the dicot root. OpenStax Biology In dicot stems, vascular bundles are arranged in a ring toward the stem periphery.
In monocot stems, the vascular bundles are randomly scattered throughout the ground tissue. In a dicot stems, vascular bundles are arranged around the periphery of the ground tissue. The xylem tissue is located toward the interior of the vascular bundle, and phloem is located toward the exterior.
Depending on what kind of plant is growing, a great tree or a wildflower, the stem may become a thick trunk with layers of vascular cambium, cork and hard bark or a more herbaceous plant. The trunk of a tree is its main stem. And, yes plants can have more than one stem. The stem that branches is called a branch. Stems may be long, with great distances between leaves and buds branches of trees, runners on strawberriesor compressed, with short distances between buds or leaves fruit spurs, crowns of strawberry plants, dandelions.
All stems must have buds or leaves present to be classified as stem tissue. An area of the stem where leaves are located is called a node.
Nodes are areas of great cellular activity and growth, where auxiliary buds develop into leaves or flowers. The area between nodes is called the internode. Nodes are protected when pruning back a plant. Destruction of the nodes can result in long non-fruiting branches.
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STEM FUNCTION Stems serve as conduits pipelines for carrying water and minerals from the roots upward to the leaves utilizing the xylem tissue and for carrying food from the leaves where food is manufactured through the process of photosynthesis down to the roots utilizing the phloem tissue.
Stems provide support for the leaves and reproductive structures flowers, fruit, and seeds of the plant. Stems are also used for food storage as in potatoes and onions and in plants with herbaceous green-colored stems they help manufacture food just as the leaves do. Taking cuttings from native plants to propagate them is especially helpful in preserving what is left of many species.
There is no digging or destroying plants. Forest communities are not damaged. The process of removing a plant part then having that part grow into a genetically exact replica of the original plant is called cutting propagation. It is a plant cloning technique. The plant part that is removed is called a cutting. Plants can be propagated from root cuttings, leaf cuttings, stem cuttings, etc.
Old, mature plants are often more difficult to root than young, vigorously growing plants. Using new growth on a mature plant may not root. Always try to use young plants. Always place cuttings in water as soon as it is cut. You can wrap the cut end of a cutting in wet paper towels and place in plastic bags if you do not have a tub of water. If the cutting wilts it may not fully recover and may not develop roots. Always take cuttings when the temperature is above freezing. Research has demonstrated that cuttings collected when temperatures were above freezing and stored in plastic bags or moist burlap in a refrigerator rooted in higher percentages than fresh, unstored cuttings taken when shoots were frozen.
Some amazing Cascadian bioregion native plants that root from branches are: All are great attractors of important pollinators and Snowbush will fix nitrogen in the soil. The first peoples of Cascadia built summer fishing and hunting huts along marshes and streams by placing freshly cut Willow in circles.
Today, some wonderful garden trellis have been erected using live Willow. The angiosperms are a large group and include herbaceous plants, shrubs, grasses, and most trees. Bud — an undeveloped or embryonic shoot and normally occurs in the axil of a leaf or at the tip of the stem.
Recognizing buds is important under two circumstances when trying to identify plants. Cotyledon — A seed leaf. A leaf of the embryo of a seed plant, which upon germination either remains in the seed or emerges, enlarges, and becomes green.
Heavenly Stems and Earthly Branches
Crowns — is a region of compressed stem tissue from which new shoots are produced, generally found near the surface of the soil. Crowns strawberries, dandelions, African violets are compressed stems having leaves and flowers on short internodes.
Dicot —comprising seed plants angiosperms that have two cotyledons in their seed. Examples of dicots flowering plants are more families sunflowers, peas, geranium, rose, magnolias, maples, oaks and willows.
Internode — the part of a plant stem between two of the nodes from which leaves emerge. Monocot — comprising seed plants that produce a seed embryo with a single cotyledon and parallel-veined leaves: Alismatidae; Arecidae; Commelinidae; and Liliidae.