which about parenchyma ,collenchyma and sclerenchyma.......
Answer in points please
Answers
Parenchyma, in plants, tissue typically composed of living cells that are thin-walled, unspecialized in structure, and therefore adaptable, with differentiation, to various functions.
Collenchyma tissue is composed by elongated living cells of uneven primary thick walls, which possess hemicellulose, cellulose, and pectic materials. It provides support, structure, mechanical strength, and flexibility to the petiole, leaf veins, and stem of young plants, allowing for easy bending without breakage.
Sclerenchyma tissue, when mature, is composed of dead cells that have heavily thickened walls containing lignin and a high cellulose content (60%–80%), and serves the function of providing structural support in plants. Sclerenchyma cells possess two types of cell walls: primary and secondary walls.
☞ AnSwer :-
➠ Parenchyma :-
- It forms the majorcomponent within organs.
- The cells of theparenchyma are generally isodiametric.
- Their walls are thin and madeup of cellulose.
- They may either be closely packedor have small intercellular spaces.
- Theparenchyma performs various functions likephotosynthesis, storage, secretion.
➠ Collenchyma :-
- It is present in layers below theepidermis (hypodermis) in dicotyledonous plants.
- It is foundeither as a homogeneous layer or in patches.
- Itconsists of cells which are much thickened at thecorners due to a deposition of cellulose,hemicellulose and pectin.
- Collenchymatous cellsmay be oval, spherical or polygonal and oftencontain chloroplasts.
- Intercellularspaces are absent.
- They provide mechanicalsupport to the growing parts of the plant such asyoung stem and petiole of a leaf.
➠ Sclerenchyma :-
- It consists of long, narrow cellswith thick and lignified cell walls having a few ornumerous pits.
- They are usually dead and withoutprotoplasts.
- It provides mechanical support to organs.
- On the basis of variation in form,structure, origin and development, sclerenchymamay be either fibres or sclereids.
- Fibers– these arethick-walled, elongated and pointed cells,generally occuring in groups, in various parts ofthe plant.
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➠ MoRe to know........
- Dermal tissue covers the outer surface of herbaceous plants.
- Parenchyma, collenchyma, and sclerenchyma cells are common in the ground tissue.
- Vascular tissue transports food, water, hormones and minerals within the plant.
- Vascular tissue includes xylem, phloem, parenchyma, and cambium cells