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71.
Carotenogenesis in mung been seedlings has been shown to beunder phytochrome control. Dark-grown seedlings contain moreindividual carotenoids than light-treated ones, but total carotenoidsare greatly increased by light. As expected, chlorophyll wassynthesized after a lag period on transferring etiolated seedlingsto the light, and there was an increase in total chlorophylland a parallel increase in total carotenoids. CPTA [2-(4-chlorophenylthio)-triethylamine hydrochloride]-treatedseedlings showed a decrease in both total carotenoids and totalchlorophylls. The usual effect of CPTA was also observed withmung bean seedlings, namely that lycopene, normally absent,appeared and increased to 17 per cent of total carotenoids afteran eight-day treatment. A cis-lycopene, possibly poly-cis-lycopene,was observed for the first time in CPTA-treated tissues. Onlyin the presence of CPTA but not on its removal was it possibleto show an inverse relationship between ß-caroteneand lycopene. This suggests that CPTA may not act as a cyclaseinhibitor in green tissues, cyclase being the enzyme/s involvedin the cyclization of carotenes. Phaseolus aureus Roxb., mung bean, carotenes, lycopene, xanthophylls, chlorophyll, 2-(4-chlorophenylthio)-triethylamine hydrochloride  相似文献   
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For the past 20 years, our laboratory has been involved in studyingthe endocrine control of calcium balance in the killifish, Fundulusheteroclitus. We have surveyed almost all endocrine systemsand discovered two main ones directly involved in plasma calciumregulation. They are the pituitary gland and the corpusclesof Stannius. When fish adapted to low-calcium seawater werehypophysectomized, hypocalcemia and tetany were observed. Whenfish adapted to high-calcium seawater were Stanniectomized,hypercalcemia was seen. In both cases, other electrolytes wereunaffected and replacement therapy corrected the plasma calciumchanges. We have tried to characterize the active principlesin both glands. We discovered that prolactin is hyperacalcemic.The pituitary gland also seems to contain a second hypercalcemicfactor which may be located in the PAS-positive pars intermediacells. For the Stannius corpuscle factors, we developed a bioassayand named the active substance(s) hypocalcin. In collaborationwith Dr. Hirofumi Sokabe at Jichi Medical School, Japan, weshowed that the Stannius corpuscles also contain a renin-likesubstance capable of generating a hypocalcemic angiotensin-likesubstance. The exact chemical nature of the hypocalcemic substanceis being investigated. Calcium balance in the whole fish wasalso studied with 47-calcium. These studies were carried outin collaboration with Dr. Nicole Mayer-Gostan at Villefranche-sur-Mer,France. We discovered that killifish depend on the environmentrather than bone as a calcium reservoir. Hormones may be involvedin the exchanges with the environment.  相似文献   
74.
The carotenoids found in adult kite swallowtails ( Graphium spp.) and the Danaid glassy tigers ( Ideopsis, Tirumala and Parantica ), butterflies with exposed blue/green pigmented wing membranes (which contain pterobilins) and a modified scale vestiture, were compared with those of related species of Papilios and Danaids with concealed wing membranes an an entire scale vestiture. It was found that both the kite swallowtails contained only lutein, and even lacked β-carotene, the first known instance among butterflies. This was presumably due to selective storage by the larva since the food-plant was found to be rich in varied carotenoids. A possible link between the high concentration of pterobilins in the wing membrane and the lack of carotenoids is discussed.  相似文献   
75.
A technique is described which indicates by u.v. fluorescence the concentration of caffeoylquinic, chlorogenic and isochlorogenic acids in roots of germinating lettuce and carrot. The surface fluorescence of radicles from lettuce root aphid (Pemphigus bursarius) resistant seedlings was more intense than for susceptible seedlings, attributable to the higher concentration of isochlorogenic acid. In contrast, radicles of carrot seedlings resistant to carrot fly (Psila rosae) were less fluorescent than susceptible seedlings, corresponding to the lower concentration of chlorogenic acid in resistant seedlings. The technique is non-destructive and has been developed to distinguish between cultivars or breeding lines potentially resistant to these insect pests.  相似文献   
76.
Studies on the herbicidal activity of 3,5–dibromo-4–hydroxybenzonitrile (bromoxynil) and 3,5–dibromo-4-hydroxyphenyl methyl sulphone (bromoxysone) have been extended to include 3,5–dibromo-4-hydroxyphenyl methyl sulphide (bromoxyside), its esters and other related compounds. Bromoxyside produced chlorotic effects in barley and wild oat seedlings, the herbicidal activity being similar to that of bromoxysone but quite different to that of bromoxynil. A range of aliphatic and aromatic esters of bromoxyside were prepared and examined as herbicides using barley and wild oat seedlings as test plants. The acetate and propionate were the most active against both species. No compound tested was more herbicidal to wild oat than to barley. Introduction of a further bromo or methyl ring-substituent into bromoxyside removed herbicidal activity. Spraying plants of differing age showed that the herbicidal effect was greater when the plants were small.  相似文献   
77.
This study reports the results of mate-choice experiments betweenresident and non-resident individuals of the simultaneous hermaphonteland snail Helix aspersa. Snails from different sites differedin their mating proclivity, which resulted in non-random matingin laboratory mate-choice tests. Those snails with the highermating propensity therefore tended to mate with their own typeand tended to be chosen as partner because they were also activelyseeking mates. Keeping snails under crowded conditions did noteffect a lasting influence on mating behaviour in laboratorytests, despite the decline in copulatory behaviour under crowdedfield conditions. (Received 7 November 1994; accepted 31 August 1995)  相似文献   
78.
79.
Food consumption by juvenile and adult specimens Limicolariaflammea was measured as dry weight of food eaten. The snailwas fed weekly for 15 months on four types of food (lettuce,potato, apple and carrot) and chalk provided, hence an opportunityto select for food. Juvenile snails showed greater selectivitydepending on whether the food was needed for somatic growthor reproduction. On the other hand, when fed exclusively onone each of the same food items and given no opportunity tochoose, the snails grew better on the same food items they selectedin the choice experiment. The absorption efficiencies (AD) werehigh, the utilisation efficiency (ECI) was 1–13% and showeddistinct peaks corresponding to egg production. Values for ECDwere 1.25–15.5%. Variation in growth rates was due mainlyto utilisation efficiencies of the four foods tested. Largeamounts of chalk were eaten during the period of somatic growthand greatly reduced during the reproductive phase of L. flammea.The significance of these findings to the snails ecology isdiscussed. (Received 9 April 1991; accepted 11 June 1991)  相似文献   
80.
Density effects on growth and sexual maturity in laboratory-keptLimicolaria flammea MÜller are described; high densityresults in low growth, higher mortality and a delay in sexualmaturity. (Received 9 April 1991; accepted 11 June 1991)  相似文献   
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