Active gibberellin (GA(1)) is an important mediator of thermoperiodic growth in pea. Plants grown under lower day than night temperature (negative DIF) elongate less and have reduced levels of GA(1) compared with plants grown at higher day than night temperature (positive DIF). By comparing the wild type (WT) and the elongated DELLA mutant la cry(s), this study has examined the effect of impair...

An important step in understanding influence of growth environment on carbon metabolism in plants is to gain a better understanding of effects of light quality on the photosynthetic system. Electron microscopy was used to study chloroplast ultrastructure in developing and fully expanded leaves of tobacco (Nicotiana tabacum L. cv Burley 21). Brief exposures to red or far-red light at the end of ...

A procedure was developed for extracting polysomes from tobacco (Nicotiana sp) leaves. Unexpanded leaves ground in a medium consisting of 200 mm tris-HCl, pH 9, 400 mm KCl, 200 mm sucrose, and 35 mm MgCl(2) yielded larger amounts of polysomes with less degradation than polysomes from leaves extracted with buffers of lower ionic strength or pH. Extraction of polysomes from expanded leaves requir...

Quercus suber L. (cork oak) leaves were analyzed along one annual cycle for cuticular wax content and chemical composition. This species, well adapted to the long dry summer conditions prevailing in Mediterranean, has a leaf life span of about year. The revealed seasonal variation with coverage increase from newly expanded (115.7 µg/cm2 spring) maximum value fully (235.6 after summer). Triterpe...

ABSTRACT Salt stress is a major production constraint in wheat. The maintenance of low Na+ accumulation the leaves may improve tissue tolerance against salt stress. A field experiment was conducted to discriminate twenty wheat genotypes, based on leaf as criterion for tolerance, and evaluate effect sodium biomass production, physiological yield traits genotypes grown saline-sodic environment. c...

trichosanthes kirilowii, an important economic plant in china, is sensitive to chilling. to investigate the effect of abscisic acid (aba) treatment on the chilling tolerance of trichosanthes kirilowii maxim, different concentrations of aba were sprayed on trichosanthes kirilowii leaves and the resulting catalase (cat) and superoxide dismutase (sod) activities and the malondialdehyde (mda) conte...

We assessed the toxicity of permethrin residues from barrier treatments for mosquito control on monarch butterßy (Danaus plexippus L.) larvae and adults. The motivation for this study was an absence of work on the effects of this commonly used insecticide on nontarget herbivorous insects and the fact that monarchsÕ host plant, milkweed (Asclepias spp.), is often found in treated areas. In one e...

Levels of asparaginase activity from developing pea leaves (Pisum sativum) were found to change on a daily basis, increasing during the light period and decreasing in the dark. During extended periods of light, high levels of activity were maintained, while prolonged dark reduced activity to a low value. Half-expanded leaves exhibited the greatest change in activity over the photoperiod. Very y...