Gibberellin (a growth hormone) was first extracted from this fungus. Treatment given to seeds when they are shaken vigorously.Ĭompounds which compete with the auxins for the reactive site e.g., TIBA, 4-chlorophenoxy isobutyric acid, 2, 6-dichlorophenoxy acetic acid, 2, 4-dichIoroanisole.Ī fungus causes “Foolish seedling disease in rice plant in Japan. Phytochrome protein chromophore: open chain tetrapyrrole dimer. Takes place due to photo- oxidation by blue light and dark oxidation by IAA oxidase. Phytochrome P 660/P 730 red/far red absorbance peaks in red and blue studied by difference spectra reach photoequilibrium because of overlap of spectrum 85 red/15 far red. The different aspects or appearances of plants in different seasons of a year. An improved auxanometer over the arc auxanometer. Register total growth, rate of growth at specific time and overall pattern of growth. Inducing synthesis of carotenoids and turns green organges into yellow. It is a regulatory pigment which regulates several light-dependent developmental processes in plants. The sensitivity of seeds to the effect of red and far-red wavelengths of light is due to the presence of phytochrome. The control of development of form (i.e., morphogenesis) by light. Even 1 ppm of ethylene prevents the opening of flower buds. Sleep disease (in rolling of petals in opened (lowers) is caused by ethylene. (ii) There is a tendency of the intensity of sensation to vary as logarithm of the stimulus.Ĭytokinin prevents chlorophyll degradation, hence ageing. (i) Within limits, the equal relative differences between two stimuli of the same type are equally perceptible. Time required for the effect of a response to disappear. The period required for a stimulus to exhibit response. The minimum lime required for a stimulus to become effective.
Instrument which can eliminate the effect of gravity and allow a plant to grow horizontally by slowly rotating it. They affect flowering, fruiting and sex expression. Removes apical bud, dwarfism, inhibit seed germination and seedling growth, overcome apical dominance, break bud dormancy, reduce leaf growth and curvature movements, stimulate growth of primary root but inhibit growth of lateral roots.
Promotes the liberation of a water soluble xyloglucan from the cell wall. Most widely occurring cytokinin, isolated from Pseudomonas tumefaciens. Plants having deliquescent stem have poor apical dominance while plants having excurrent habit (palms, conifers, polyalthia) have greater apical dominance. Used for recording plant growth in seconds. Hitchcock and Zimmerman exhibited that flowering in Nicotiana can be enhanced by auxins.Īuxins are synthesised mainly in apices and exhibit polar transport.
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