Sclerenchyma of bundle sheath external and internal intrafascicular cambium
Functions: (i) It provides sharpness to the soft stem, (ii) The outer part of the ground tissue takes part in photosynthesis. (ii) It stores food. Vascular Strand: It consists of a large number (4) of oval vascular bundles that are scattered throughout the ground tissue. Such a vascular strand is called an atactostele. There are external vascular bundles or round vascular bundles. smaller than inside. Each vascular bundle is surrounded by a sheath of sclerenchyma. This is known as bundle sheath.
The sclerenchyma of the bundle sheath is thicker on the outer and inner side. Each vascular bundle contains both phloem and xylem. Therefore, it is combined. Phloem is on the outer side while xylem is on the inner side of the same radius. Such a vascular bundle is called collateral. A strip of intrafascicular cambium is absent between the phloem and xylem. Therefore, the vascular bundles are closed. Phloem consists of both protophloem and metaphloem. The protophloem is on the outer side.
Much of it is crushed into the vascular bundles of maize. Phloem is made up of 3 types of sieve tubes, companion cells and some filaments. Phloem lacks parenchyma. Xylem is in the form of V or Y. There exists a distinction between protoxylem and metaxylem. The protoxylem is towards the central axis while the cells metaxylem is towards the outer side. Such xylem is called endarch. Xylem contains all the elements.
The 4 elements are vessels, tracheids, parenchyma and fibers. Metaxylem forms two sides of Y or V. It is represented by two large round or oval vessels. They are connected by means of polygonal tracheids. Both vesels and tracheids have a stack of metaxylem near Thickenings. The protoxylem forms the tail of the V or the tail of the Y. It consists of two components, persistent and degenerate. The persistent part consists of 1 to 3 small, oval vessels, parenchyma cells and some fibers. The vessels have spiral or annular concentricity. The degenerated part contains a cavity called the protoxylem cavity or lacuna. It is licinaceous or schizolysiginous in origin.
The protoxylem cavity usually contains water. The cavity is absent or reduced in small vascular bundles in contact with the sclerenchymatous hypodermis. Reasons for identification: (ii) Indivisible land tissue. (iii) Vascular bundles scattered throughout the ground tissue. (iv) Each vascular bundle with sclerenki- Matamas sheath. (v) Conjunction of vascular bundles, collateral and closed, (vi) Vessels round (vii) Occurrence of protoxylem cavity.
Evolution doesn't just follow the laws of biology
Child psychology studies the living entity. Growth and development take place according to the laws of biology. So child psychology is a biological science but the development of a child is not just according to the laws of biology. The child lives in a social environment right from birth. It affects its formation. In particular, family, school and neighbors have a profound effect on a child's personality. So child psychology is a biological social science. Child psychology is a natural science. There are two types of science: natural science and idealistic science.
Natural Science: Natural science studies how an event or phenomenon actually occurs. For example, physics says that a thrown ball falls on the ground. Magnets attract iron.
Idealistic Science: Idealistic science is the science that studies ideals. This science studies how a person or human being should behave. For example, compassion should be shown towards the victims. etc. rules are followed.
Like in the olden days, it was often said that if a child doesn't study, to motivate him to study, if he doesn't study, who will give you the 'bride'? The study of the independent branch of child psychology began when psychologists realized this truth. Child psychology is a biological social science.
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