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The effect of lincocin (a plastid protein synthesis inhibitor) treatment on the greening process of bean (Phaseolus vulgaris L.) leaves have been studied. In comparison with control leaves treated ones had a decreased rate of chloroplast development. They had a marked chlorophyll deficiency and a decreased chlorophyll a/b ratio. Some long and short wavelength forms of chlorophyll a were lacking as evidenced from the absorption spectra at 25°C and the fluorescence spectra at 77°K. The –14CO2 fixation was inhibited by 80–90% in treated leaves. The fluorescence induced by the measuring light was greater in the treated leaves than in the control ones, and the kinetics of the decline of the relative fluorescence intensity were also different. Electron microscopic studies showed macrogranum-like structures and incomplete membrane vesicles in the treated plastids. After longer treatment a destruction of membranes was observed. The results indicate some structural and functional membrane deficiencies and instability of the membranes. 相似文献
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DIDIER FOURGON IGOR EECKHAUT DEVARAJEN VAÏTILINGON MICHEL JANGOUX 《Invertebrate reproduction & development.》2013,57(3):155-165
Summary The larval development of the ophiocomid ophiuroid Ophiomastix venosais described using SEM. The gastrula transforms into a uniformly ciliated early larva which progressively changes into a lecithotrophic late premetamorphic larva with a continuous bilateral ciliated band. This stage is short-lived and equivalent to a highly reduced ophiopluteus. Comparisons between O. venosa and other ophiuroid species whose development has been investigated suggest that, whatever the developmental mode (lecithotrophic or planktotrophic), a pluteus stage always occurs in ophiuroids with planktonic development. Two metamorphic stages were identified, the late metamorphic larva differing from the early one by the closure of the larval mouth. The appearance of the permanent mouth marks the end of the metamorphosis. The postlarva still possesses remnants of larval features. The transformation of the reduced ophiopluteus into a barrel-shaped metamorphic larva with transverse ciliated bands, a vitellaria larva, is followed. The possible occurrence of a unique type of metamorphic larva in non-brooding ophiuroids is discussed. Verification of this, however, needs further SEM investigations on metamorphic larva from species having “regular” planktotrophic development. 相似文献
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L. M. Vasilyak A. I. Vasiliev S. V. Kostyuchenko D. V. Sokolov A. Yu. Startsev N. N. Kudryavtsev 《Plasma Physics Reports》2011,37(13):1173-1177
For the first time, cathode and anode drops of powerful low-pressure amalgam lamps were measured. The lamp discharge current
is 3.2 A, discharge current frequency is 43 kHz, linear electric power is 2.4 W/cm. The method of determination of a cathode
drop is based on the change of a lamp operating voltage at variation of the electrode filament current at constant discharge
current. The total (cathode plus anode) drop of voltage was measured by other, independent ways. The maximum cathode fall
is 10.8 V; the anode fall corresponding to the maximal cathode fall is 2.4 V. It is shown that in powerful low pressure amalgam
lamps the anode fall makes a considerable contribution (in certain cases, the basic one) to heating of electrodes. Therefore,
the anode fall cannot be neglected, at design an electrode and ballast of amalgam lamps with operating discharge current frequency
of tens of kHz. 相似文献
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