أكاديميا - كولنز معاجم الجيب العلمية - البيولوجيا انكليزي - فرنسي - عربي الحرف ٣_ t

Academia - Collins Scientific Pocket Dictionaries - Biology
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transpiration stream
water for transpiration

Transpiration current. The flow of water through the plant caused by transpiration. Water evaporates through stomata, which leads to more water being drawn by osmosis from neighboring leaf cells (spongy mesophyll cells).

The forces of osmosis released in this way cause the water to eventually withdraw from the xylem vessels in the leaf, which leads to water being withdrawn from the stem and roots by the xylem vessels, meaning that the evaporation of water from the leaves causes the flow of water (and with it mineral salts mineral salts) via the plant.

Tissue cells
Transpiration stream
Spongy medial
The lower epidermis of the leaf
Kesem pot
Root hairs
Air vacuum
Change, guard cell
Kesem pot


tropism
tropism m

Plant growth movement in response to a stimulus, such as light, for example.

These movements are related to the direction of the stimulus, so the related plant organ grows toward it or away from it. It is called tropism by adding a prefix indicating the stimulus.
Examples of tropism include:

(a) geotropism - response to Earth's gravity.
(b) Phototropism - response
For light.
(c) Chemotropism - response to chemicals.
(d) Hydrotropism - response to water.
Tism can be positive or negative depending on whether the response is towards the stimulus or not
.nastic movement See

The importance of tropism stems from the fact that it makes the plant grow in a way that obtains the maximum benefit from the environment in terms of water, light, etc.

Trophism results from the plant hormone, or auxin, which accelerates growth by stimulating elongation, elongation, cell division, and cell division. The uneven distribution of auxin causes unbalanced growth and leads to plant bending.


trypsin
trypsine f

Trypsin. Protease enzyme secreted by the pancreas of a vertebrate animal. See duodenum.

tuber
tubercule m

tuber. Organ vegetative reproduction in flowering plants. Tubers can be formed from stems or roots, which consist of a food store and buds from which new plants emerge.

Root tuber (such as dahlia)
Stem tuber (such as potato)


turgor
turgescence f

swelling. State of plant cell after maximum water absorption. Water enters the cell it surrounds by osmosis, causing the vacuole to expand and pushing the cytoplasm into the cell wall, making the plant cell tough and strong. Such a cell is said to be swollen or turgid.

Water enters by osmosis
swollen cell
Submerged in water
Selective permeation membrane

plant cell
Cell wall
Small gap
Cytoplasm
nucleus

The swollen cells are important in supporting the plant and giving it strength and shape. Young plants depend entirely on swelling for erection, while support for older plants is provided by the formation of wood.

tympanum (or tympanic membrane)
tympan m

Drum. (or tympanic membrane). A thin membrane separates the outer ear from the middle ear in tetrapods, i.e. the ear drum. See ear.