(a): Minerals absorbed by roots move to the leaf through xylem. Minerals absorbed by root move to the leaf throughġ2. NADP is a coenzyme which is reduced to NADPH 2 the hydrogen required for the formation of NADPH 9 comes from the breaking of water molecule.ġ2. (d): The excited chlorophyll transfer an electron from chlorophyll through various steps until the reduction of NADP is completed. It takes place in the presence of light only.ġ1. Light reaction is associated with the grana of the chloroplasts. Light energy absorbed by pigment in the two systems is ultimately trapped by the P 700 and P 6g0. While pigment system II is strongly fluorescent. Pigment System I is relatively very weakly fluorescent (d): The dark reactions or Blackman’s reactions or biosynthetic phase involves three steps: (i) which is fixation of CO 2, (ii) Reduction of CO 2 and (iii) synthesis of other compound from glucose. Carbon dioxide joins the photosynthetic pathway inġ0. Cytokinins bring about division even in permanent cells.ġ0. Cytokinins are essential for cytokinesis though chromosome doubling can occur in their absence. They contain kinetin and related compound generally called as kinins chemically, cytokinins are degradation product of adenine, ATP, NAD and NADP. (c): Cytokinin has a very specific effect on cell division (cytokinesis), hence the name cytokinin. Hormone primarily connected with cell division isĩ. Shelf life of cut shoots and flowers is krolonged by employing the hormones.ĩ. Cytokinins applied to marketed vegetables can keep them fresh for several days. (b): Cytokinin are plant growth hormones which are basic in nature cytokinins induce formation of new leaves chloroplasts in heaves, which inturn keeps the leaves green for a longer duration of time. Cut or excised leaves remain green for long if induced to root or dipped inĨ. The enzymes solubilize the reserve food of the seed.Ĩ. During seed germination, especially of cereals giberrelin stimulates the production of some messenger RNAs and then hydrolytic enzymes like amylases, lipases, proteases. Giberellins are synthesized in the apical shoot buds, root tips and developing seeds. Giberellins are weakly acidic growth hormones having ring structure and which causes cell elongation of intact plants in general and increased internodal length of genetically dwarfed plants. (a): Gibberellins promotes seed germination. Borthwick, Hendicks and Parker in 1952, discovered phytochrome, which is a pigment received light existed in two inter convertible forms active form and inactive form.ħ. (c): Phytochrome is a photoreceptor molecule which mediates several developmental and morphogenetic responses of plants to light. Movement of leaves of sensitive plant, Mimosa pudica are due toĦ. When they are flaccid, the tension from the wall is released and the stomatal aperture closes.ĥ. As a result, the stomatal aperature opens. When turgid, they swell and bend outward. Stomata open and close due to turgor pressure of guard cells.
(d): The pressure that develops in a cell due to osmotic diffusion of water inside it, is called turgor pressure. A good antitranpirant increases leaf resistance but does not affect the mesophyll resistance.Ĥ. These are some chemicals whose limited application on the leaf surface reduce or checks transpiration.
(b): Phenyl mercuric acetate (PMA) results in reduced transpiration.
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