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Increase in fluence rates of white light over the range of 5to 80 µmol m2 s1 brought about a correspondingincrease in amounts of anthocyanin production in shoots of Zeamays L. seedlings. Roots also exhibited a similar relationshipbetween increased fluence rate and increased anthocyanin productionover the range of 5 to 40 µmol m2 s1 whereasfluence rates above 40 µmol m2 s1 broughtabout decreases in anthocyanin production. Rates of productionand amounts of accumulation of anthocyanin in both shoots androots were found to vary with the age of the seedlings at thetime of exposure to light. Age, fluence rates, anthocyanin, seedlings, Zea mays 相似文献
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Anthocyanin production was impaired in both roots and shootsof Zea mays seedlings germinated on 1 and 2 mM concentrationsof four barbiturates having different lipid/aqueous partitioncoefficients. The severity of impaired anthocyanin productionwas greater in those seedlings treated with the higher lipidsoluble barbiturates irrespective of the concentrations used.Indirect evidence is presented which indicates that barbituratesinterfere with normal membrane physiology responsible for anthocyaninproduction. Anthocyanin, barbiturate, seedlings, Zea mays 相似文献
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Rice seedlings germinating under water under natural illuminationshow vertical shoot geotropism when the environmental conditionsare favourable for greening of the submerged seedlings. Whenthe submerged seedlings are germinated under environmental conditionswhich are unfavourable for greening, transverse geotropism ofthe shoots becomes manifest. Continuous exposure of the submergedgerminating seedlings to ethylene did not prevent greening ofthe shoots and did not prevent the shoots from manifesting verticalgeotropism. Evidence obtained from this and previous investigationsindicates that oxygen availability is one of the most, if notthe most, significant environmental factor associated with themanifestation of transverse and vertical shoot geotropisms ofrice seedlings germinating under water. 相似文献
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Rice seedling germination and developmental behaviour were examinedin the presence of six different barbituric acid derivatives.The relationship between liquid/aqueous partition coefficientsof barbiturates and their interference with, but not completeinhibition of, normal mitochondria1 oxidative metabolism observedin animal mitochondria in vitro also appear to be factors influencingthe effects of these compounds on the germination and developmentalbehaviour of the rice seedlings described in this investigation.Evidence is presented here which points to normal oxidativemetabolism as being a necessary requisite for normal light responseand normal morphogenetic development in germinating rice seedlings. 相似文献
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Rice seedlings germinated in the dark in O2-deficient and normalair environments manifest dimorphism and are designated hereas d and d+ plants. Both d and d+ seedlings lackchlorophyll but the d plants are stark-white whereasthe d+ plants are yellow or yellow-green in appearance. Riceseedlings germinated in the light under O2 deficiency also lackchlorophyll and manifest the same developmental characteristicsas the d dark-germinated seedlings. Thus, in an O2-deficientenvironment, light-germinated rice seedlings behave as thoughthey were germinated in the dark under O2 deficiency. Exposureof the dark-germinated d and d+ seedlings and the light-germinatedd seedlings to normal air in the light brings about chlorophyllformation and normal morphogenetic development in all threetypes of germinating seedlings. Thus O2 exerts a critical influenceon the response of germinating rice seedlings to light energywith respect to their normal morphogenetic development. 相似文献
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Rudimentary adventitious root primordia were observed in optically-sectionedFeulgen-stained hypocotyls of 8-d-old lettuce seedlings germinatedin the dark and in a low light intensity environment. It issuggested that formation of these primordia may represent anaspect of normal development in the seedling. Adventitious, root primordia, hypocotyls, lettuce, Lactuca sativa 相似文献
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High population densities of germinating rice seedlings in initiallyair-saturated sealed aquatic environments exhibited dseedling growth consisting solely of coleoptile emergence inlight and dark environments. Residual oxygen tensions of 1723%of the initially air-saturated water containing the dseedlings were evident after 15 d in both the light and dark.Coleoptiles of all d seedlings were stark white in appearance,lacked protochlorophyllide, and contained proplastids and amyloplasts,there being no evidence of normal etioplast development in thelight or dark and no chloroplast development in the light. Thus,complete environmental anoxia was observed to be unnecessaryfor inhibiting normal chloroplast photomorphogenesis in coleoptilesof light-germinated rice seedlings. Increasing the oxygen tensionsof the 15-d-old aquatic environments of light- and dark-germinatedd seedlings placed in the light resulted in normal chloroplastphotomorphogenesis in coleoptiles, shoots, and roots. Key words: Oryza sativa, environmental anoxia, chloroplast photomorphogenesis, rice coleoptiles 相似文献