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ARRANGEMENTS IN VASCULAR BUNDLES RADIAL: When xylem and phloem in a vascular bundles are arranged in alternate manner on different radii then such arrangement is called Radial arrangement. CONJOINT: Xylem and Phloem when arranged on same radii in the vascular bundles is considered as Conjoint. OPEN: When xylem and phloem are seperated by vascular cambium. Such arrangement with cambium is considerd as Open vascular bundles as in Dicots. CLOSED:  Vascular cambium is absent in between the xylem and phloem such arrangement of vascular bundles with no cambium is called Closed vascular bundles as in Monocots.

 TWO MAIN DIFFERENCES BETWEEN C3 AND C4 PLANTS: There are two main differences which exhibits in C3 and C4 plants internally. They are: 1. Kranz anatomy in C4 plants and absent in C3 plants. 2. Photorespiration in C3 plants and absent in C4 plants. Now this explanation will help you to understand the differences. In C4 plants, internal strucutre of leaf has bundle sheath cells around the vascular bundlles. Such anatomy of leaves are considered as Kranz anatomy . The cells contain chloroplast and it is impervious to gases exchange and no intercellular spaces in it. In C3 plants photorespiration process takes place. It is stated that photorespiration is a wasteful process because it does not yield ATP and NADPH but rather it utilises ATP to release CO2. In C4 plants it lacks because they have a mechanism that increase CO2 concentration and has a capacity to minimise the oxygenase activity. so in  C4 plants productivity and yield is better th...

PIGMENTS: Pigments are the substances that have an ability to absorb the light at different wavelengths. There are four types of pigments in plant. They are: 1.Chlorophyll a- (bright or blue-green) 2.Chlorophyll b-(yellow green) 3.Xanthophylls-(yellow) 4.Carotenoids-(yellow to yellow-orange)  * Chlorophyll a is the most abundant pigment responsible for trapping light. Other pigments are accessory pigments which protect chlorophyll a from photo-oxidation .

   In plants, growth starts from the germination of seeds. Then it develops internally and externally forming various parts. Plants undergoes primary and secondary growth which differs from each other in many ways. Primary growth in plants exhibits in plants within 1 year then plant undergoes secondary growth. PRIMARY GROWTH IN PLANTS: Primary growth in plants takes place inside the stem. Both dicotyledenous and monocotyledenous plants undergoes primary growth, and of course they show some variations. IN DICOTYLEDENOUS PLANTS: Stem consist of three zones . They are: 1.EPIDERMIS 2.GROUND TISSUE 3. STELE 1.EPIDERMIS: It is the outermost layer covered by cuticle. Epidermis protects the inner parts of the stem. Cuticle covers the epidermis and helps in transpiration. It may have trichomes and stomata. 2. GROUND TISSUE: The tissues other than vascular bundles and epidermis is considered as ground tissue. It is again divided in...

STOMATA: Stomata are the structures which is present on the epidermis of leaf mainly but in some plants it is also present in stems. *In Monocots stomata is dum-bell in shape *Whereas in Dicots it is bean shaped. Stomata consist of two types of cells. They are: 1. Guard cells 2. Subsidiary cells. 1. Guard cells: In Dicots the guard cells are bean shaped whereas in monocots guard cells are dum-bell shape. There are two guard cells in each stomata. As the stomata is bean shaped, the curved walls of stomata are thin and it has elasticity which means it has microfibrils through which water gets absorbed by the cell. A stomatal pore is present between the two guard cells. Inside the guard cells cytoplasm, organelles and chloroplast is present. Chloroplast helps in photosynthesis. When the cell absorbs the sunlight, chloroplast gets activated and forms sugars inside the cell. as a result the concentration inside the cells gets...

TRANSLOCATION OF MINERAL IONS: Different ions when reached to the xylem through active or passive transport, then further transport takes place through transpiration. The mineral elements sink at the growing regions of the plant such as the apical and lateral meristems, young leaves, developing flowers, fruits, seeds, and the storage organ. When the old parts gets dies or leaves fall off before dying the minerals get remobilised to the younger parts of the plant. Older leaves exports the minerals to the younger leaves. the elements which gets mobilised are Phosphorous, Sulphur, Nitrogen and Potassium. But the Calcium will not get mobilised. Much of the elements are carried in the form as Amino acids and related compounds. Phosphorous and Sulphur carried as organic compounds and Nitrogen is carried out as Inorganic compound. Hence, it is not that xylem transports only inorganic substances and phloem carries organic substances as it is traditionally believed. They both c...

Transpiration pull: In higher plants water is transported through xylem. This movement is accomplished by 'pulling' of water to the leaves of the plant. This is referred to as cohesion-tension-transpiration pull model  of water transport. This takes place in the higher plants . Transpiration  Less than 1 percent of water is utilized in the process of photosynthesis. Water is lost from the plants through stomata in the form of vapour on the surface of leaves. This process of removing water through stomata of leaves in the form of vapour is called as Transpiration.