Addition of either abscisic acid (ABA) or kinetin at 10−6 M to salinized media (20–120mM NaCl) induced remarkable effects on growth ofPhaseolus vulgaris plants. Whereas ABA inhibited the plant growth and the rate of transpiration, kinetin induced stimulation of both parameters.
Moreover, ABA increased proline and phosphorus concentrations in the salinized plants whilst kinetin decreased them.
ABA induced stimulation of the transport of K, Ca and Cl from root to shoot, accumulation of K, Na and Cl in root cells and
inhibits the transport of Na and accumulation of Ca. Kinetin appeared to inhibit the transport and accumulation of Na and
Cl, transport of K, and stimulates the accumulation of K and Ca as well as the transport of Ca. The highest influence of both
ABA and kinetin was mostly observed when these hormones were used in combination with the highest concentration of NaCl (120
mM) in the medium. 相似文献
Increasing salinity induced a marked reduction in the plant growth, thoughPhaseolus seedlings tolerated salinity up to 120 mM NaCI. A great reduction in sugar and protein contents occurred with increasing salinity, whereas soluble nitrogen compounds and the relative contents of the photosynthetic pigments were increased in the treated plants. Increasing Ca concentration in the salinized medium appeared to improve the plant growth and to increase the contents of saccharides and proteins in the NaCl-treated plants. This suggests that Ca could be added to salinized media to overcome the deleterious effects of salinity on the growth and productivity of leguminous crop plants. 相似文献
It is critical for spring wheat (Triticum aestivum L.) production in the semi-arid Loess Plateau to understand the impact of nitrogen (N) fertilizer on changes in N metabolism, photosynthetic parameters, and their relationship with grain yield and quality. The photosynthetic capacity of flag leaves, dry matter accumulation, and N metabolite enzyme activities from anthesis to maturity were studied on a long-term fertilization trial under different N rates [0 kg ha?1(N1), 52.5 kg ha?1 (N2), 105 kg ha?1 (N3), 157.5 kg ha?1 (N4), and 210 kg ha?1 (N5)]. It was observed that N3 produced optimum total dry matter (5407 kg ha?1), 1000 grain weight (39.7 g), grain yield (2.64 t ha?1), and protein content (13.97%). Our results showed that N fertilization significantly increased photosynthetic parameters and N metabolite enzymes at all growth stages. Nitrogen harvest index, partial productivity factor, agronomic recovery efficiency, and nitrogen agronomic efficiency were decreased with increased N. Higher N rates (N3–N5) maintained higher photosynthetic capacity and dry matter accumulation and lower intercellular CO2 content. The N supply influenced NUE by improving photosynthetic properties. The N3 produced highest chlorophyll content, photosynthetic rate, stomatal conductance and transpiration rate, grain yield, grain protein, dry matter, grains weight, and N metabolite enzyme activities compared to the other rates (N1, N2, N4, and N5). Therefore, increasing N rates beyond the optimum quantity only promotes vegetative development and results in lower yields.
Etioplast development and protochlorophyllide (Pchlide) accumulation was studied in wheat seedlings ( Triticum aestivum L. cv. Walde, Weibull) grown in darkness on gibberellic acid (GA3), gabaculine (3-amino-2,3-dihydrobenzoic acid), or on a combination of the two. The results were compared with the features of seedlings grown on water only. GA3 enhanced shoot growth and promoted etioplast development. A correlation was observed between the appearance of prolamellar bodies (PLBs) and of phototransformable Pchlide. Gabaculine, a known tetrapyrrole biosynthesis inhibitor, delayed growth, slowed down the rate of PLB formation and caused structural alterations of the etioplasts up to 48 h of germination. Gabaculine also delayed the formation of phototransformable Pchlide as well as overall Pchlide biosynthesis, as determined by low-temperature fluorescence emission in vivo. The spectral blue-shift of newly formed chlorophyllide (Chlide) was delayed in irradiated dark-grown gabaculine-grown seedlings, indicating an inhibited dissociation of Chlide and NADPH-Pchlide oxidoreductase (Pchlide reductase: EC 1.3.1.33). Thus there is a close correlation between accumulation of Pchlide and etioplast development, also under conditions when development is enhanced or delayed. 相似文献
(1) Photophosphorylation, Ca2+-ATPase and Mg2+-ATPase activities of isolated chloroplasts were inhibited 55--65% when the chemical potential of water was decreased by dehydrating leaves to water potentials (psi w) of --25 bars before isolation of the plastids. The inhibition could be reversed in vivo by rehydrating the leaves. (2) These losses in activity were reflected in coupling factor (CF1) isolated from the leaves, since CF1 from leaves with low psi w had less Ca2+-ATPase activity than control CF1 and did not recouple phosphorylation in CF1-deficient chloroplasts. In contrast, CF1 from leaves having high psi w only partially recoupled phosphorylation by CF1-deficient chloroplasts from leaves havig low psi w. This indicated that low psi w affected chloroplast membranes as well as CF1 itself. (3) Coupling factor from leaves having low psi w had the same number of subunits, and the same electrophoretic mobility, and could be obtained with the same yields as CF1 from control leaves. However, direct measurements of fluorescence polarization, ultraviolet absorption, and circular dichroism showed that CF1 from leaves having low psi w differed from control CF1. The CF1 from leaves having low psi w also had decreased ability to bind fluorescent nucleotides (epsilon-ATP and epsilon-ADP). (4) Exposure of isolated CF1 to low psi w in vitro by preincubation in sucrose-containing media inhibited the Ca2+-ATPase activity of the protein in subsequent assays without sucrose. Inclusion of 5 or 10 mM Mg2+ in the preincubation medium markedly inhibited Ca2+-ATPase activity. (5) These results show that CF1 undergoes changes in cells which alter its phosphorylating ability. Since low cell psi w changed the spectroscopic properties but not other protein properties of CF1, the changes were most likely caused by altered confurn, photophosphorylation. The inhibition of ATPase activity in CF1 in vitro at low psi w and high ion concentration mimicked the change in activity seen in vivo. 相似文献
Tomato seedlings absorbed increasing amounts of nitrate-N. The total uptake was doubled as the concentration of nitrate was quadruplicated. NO3?N absorption seemed to be accompanied by efflux of OH? ions which shift the pH of the media to the alkaline side. A minor fraction of the absorbed nitrate accumulated in the tissues while the major part was assimilated into peptides and proteins. The dry matter gain was by the end of experiment relatively higher than the control samples raised on nitrogen-free nutrient solution. Nitrate assimilation seemed to involve its reduction down to ammonia level. Since neither nitrite nor ammonia was recovered in the tissue-medium system, it was postulated that the rate of reduction was slower than the rate of product assimilation. The first step in nitrate reduction (nitrate→nitrate) appeared to be limiting while further reduction steps occurred rapidly and accompanied by simultaneous assimilation of ammonia. The enzyme responsible for the first step of nitrate reduction,i.e., nitrate reductase, was extracted from tomato shoots and roots. The activity in root extract amounted to about 30% of that of the shoot. This may suggest the localization of nitrate reduction in the leaves and realizes the relation between nitrate metabolism and photosynthesis. 相似文献
Plasmonics - This paper investigates the behavior of the surface plasmon polaritons (SPPs) on dielectric-metal interface using Ag thin film on glass substrate. The Kretschman configuration, which... 相似文献
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Plasmonics - Effect of different gold (Au) grating structures on light absorption in solar cell is investigated by finite elemental analysis using COMSOL multiphysics-RF module. The geometry of the... 相似文献