In five genotypes of cowpea (Vigna unguiculata), the influence of salicylic acid (SA) on photosynthetic activity and biochemical constituents including peroxidase activity at the genotypic level was determined. After SA treatment the total free sugar content increased in IFC 8401 and IGFRI 450 genotypes, whereas the content of total leaf soluble proteins decreased significantly in IFC 902. The high chlorophyll (Chl) (a + b) content in IFC 902 showed a good correlation with the net photosynthetic rate (PN), as in this genotype a significant increase in PN was found after the SA treatment. and Amaresh Chandra,, R. K. Bhatt.
Anthropogenic activities and improper uses of phosphate fertilizers have led to an increase in cadmium concentrations in agricultural soils. Brassinosteroids are steroid hormones that are rapidly assimilated and metabolised with beneficial roles in physiological and biochemical processes in plants. Our aim was to ascertain whether exogenous treatment with 24-epibrassinolide (EBR) can mitigate the Cd toxicity, and whether this substance can reduce the Cd accumulation in plant tissues. Furthermore, the dose response to EBR was determined following exposure to Cd in Vigna unguiculata. The experiment was a completely randomised factorial design with two concentrations of Cd (0 and 500 μM) and three concentrations of EBR (0, 50, and 100 nM). Spraying plants exposed to Cd with EBR significantly reduced the concentrations of Cd and increased nutrient contents in all tissues. The EBR treatment caused significant enhancements in leaf, root, and total dry matter. Foliar application of EBR reduced the negative effects of Cd toxicity on chlorophyll fluorescence and gas exchange parameters. Pretreatment with EBR also increased contents of pigments in plants exposed to Cd, compared with the identical treatments without EBR. Cd elevated contents of oxidant compounds, inducing cell damages, while EBR significantly decreased the concentrations of these compounds. We confirmed that EBR mitigated the negative effects related to Cd toxicity, reduced the absorption and transport of Cd, and increased the contents of essential elements. In plants exposed to Cd, the most apparent dose response was found for 100 nM EBR, with beneficial repercussions on growth, gas exchange, primary photosynthetic processes, and photosynthetic pigments, which were intrinsically connected to lower production of oxidant compounds and cell damage., L. R. Santos, B. L. Batista, A. K. S. Lobato., and Obsahuje bibliografii
In carob tree (Ceratonia siliqua) radiant energy saturated net photosynthetic rate (PN) during summer was about 10 % of the spring values. This was accompanied by a reduction in stomatal conductance (gs), which only partially explains the strong reduction in PN. Photosynthetic capacity (Pmax) and quantum yield (Φ), both measured under saturating CO2, had the maximum in spring (about 34 μmol m-2 s-1 and 0.08 mol mol-1, respectively) and both decreased in late summer to about 55 % of their spring values. Despite strong decreases in Φ, photoinhibition of photosystem 2 (PS2) was negligible or easily reversible in carob leaves subjected to summer drought, since Fv/Fm, measured in the morning, did not show appreciable changes. The recovery of affected parameters was very rapid after the first rains in late October. The chlorophyll (Chl) alb ratio in the end of the summer was 2.6, a value significantly lower than 3.6 obtained in the spring, suggesting that Chl a was preferentially reduced. and J. C. Ramalho, J. A. Lauriano, M. A. Nunes.
The present piece of work highlights the comparative effects of two active forms of brassinosteroids (BRs), 28-homobrassinolide (HBL) and 24-epibrassinolide (EBL), on growth parameters, carbonic anhydrase activity and photosynthetic parameters in Lycopersicon esculentum (cv. K-21) sampled at 45 (24 h after spray) and 60 days after sowing, under natural conditions. Out of the two active forms of BR, EBL proved better than HBL in improving the above parameters, when applied as foliar spray. Of the three concentrations (10-6 M, 10-8 M or 10-10 M) of HBL and EBL, 10-8M proved best in both cases. and S. Hayat ... [et al.].
Photosynthetic characteristics of two hybrid rice combinations, Peiai 64S/E32 and Shanyou 63, were compared at the panicle differentiation stage. As compared with Shanyou 63, the new combination Peiai 64S/E32 showed a significantly higher net photosynthetic rate (PN), apparent quantum yield of carbon assimilation (Φc), carboxylation efficiency (CE), and photorespiratory rate (RP) as well as leaf chlorophyll content, but a significantly lower dark respiration rate (RD) and compensation irradiance (Ic). It also showed a slightly higher photochemical efficiency (Fv/Fm and ΔF/Fm') of photosystem 2, a lower non-photochemical quenching (qN), and a similar CO2 compensation concentration (Γ) as compared to Shanyou 63. and Hua Jiang ... [et al.].
Forty-four genotypes from the rice germplasm were identified under photoinhibition/photooxidation and shade conditions and divided into four basic types: (1) cultivars tolerant to both photooxidation and shading, (2) cultivars tolerant to photooxidation but sensitive to shading, (3) cultivars tolerant to shading but sensitive to photooxidation, and (4) cultivars sensitive to both photooxidation and shading. Photosynthetic characteristics of a cultivar tolerant (cv. Wuyugeng 3) and a cultivar sensitive (cv. Xiangxian) to photooxidation and shading were compared. The photochemical efficiency (Fv/Fm) of photosystem 2 (PS2) and the content of PS2-D1 protein in the tolerant cultivar Wuyugeng 3 decreased less under photooxidative conditions as compared with Xiangxian. Under similar conditions, superoxide dismutase was induced rapidly to a higher activity and the active oxygen (O-) built up to a lower level in Wuyugeng 3 than in Xiangxian. Net photosynthetic rate (PN) decreased by 23 % in Wuyugeng 3 vs. 64 % in Xiangxian. Shading (80 %) during the booting stage caused only small decreases (7-13 %) in ribulose-1,5-bisphosphate carboxylase activity and PN in Wuyugeng 3 but severe decreases (57-64 %) were observed in Xiangxian which corresponded to the decreases in grain yield of the two cultivars (38 and 73 %, respectively). We described a simple and effective screening method and physiological basis for breeding crops for enhanced tolerance to both high and low irradiance. and Demao Jiao, Xia Li.
Chrysanthemum plantlets were cultivated in vitro on media with 2.0, 0.3, or 0 % sucrose, or photoautotrophically without an organic carbon source but with supplementation of the culture vessel atmosphere with 2 % CO2. The photoautotrophically cultivated plantlets showed a better growth and multiplication, higher contents of chlorophyll (Chl) and carotenoids, higher Chl a/b ratio, net photosynthetic rate and ribulose-1,5-bisphosphate carboxylase/oxygenase and phosphoenolpyruvate carboxylase activities than plantlets grown on the medium with sucrose. and C. Cristea, F. Dalla Vecchia, N. la Rocca.
Various physiological characteristics of Cj and C4 plants (14 species) grown along a salinity gradient were studied. The majority of plants occupying salt-marshes were succulent chenopods, mainly C4 annuals. The ash content of assimilating organs of plants was higher and osmotic potential lower in species grown under increasing soil salinity. The plants of the NADP-ME group accumulated more K than Na. Large amounts of Na"^ and CT characterized the NAD-ME plants and perennial C3 plants from sites with high soil salinity, Net photosynthetic rate (P^) and chlorophyll content were decreased in species grown under high salinity. Dark respiration was depressed by salinity to a lesser extent than P^.
The grapevine (Vitis vinifera L. cv. Riesling) plants subjected to water deficit were studied for changes in relative water content (RWC), leaf dry mass, contents of chlorophyll (Chl), total leaf proteins, free amino acids, and proline, and activities of ribulose-1,5-bisphosphate carboxylase (RuBPC), nitrate reductase (NR), and protease. In water-stressed plants RWC, leaf dry matter, Chl content, net photosynthetic rate (PN), and RuBPC and NR activities were significantly decreased. The total leaf protein content also declined with increase in the accumulation of free amino acids. Concurrently, the protease activity in the tissues was also increased. A significant two-fold increase in proline content was recorded. and M. Bertaminni ... [et al.].
Tartary buckwheat (Fagopyrum tataricum Gaertn) has been praised as one of green foods for humans in the 21st century. Effects of fertilization on leaf photosynthetic characteristics and grain yield of tartary buckwheat has not been yet reported in detail. Our experiment was set as a split-plot factorial. The main plots and subplots were designed by fertilizer ratio and rate as: NPK 1:1:1 (A1), NPK 1:4:2 (A2), NPK 1:2:3 (A3), and 300 (B1), 450 (B2), and 600 (B3) kg (NPK) ha-1. Our results showed that the grain yield was significantly and positively correlated with the net photosynthetic rate (PN), stomatal conductance (gs), transpiration rate (E), PAR, stomatal limitation value (Ls), chlorophyll content (SPAD value), and leaf area index (LAI), while significantly and negatively correlated with intercellular CO2 concentration (Ci) and water-use efficiency (WUE). The grain yield, PN, gs, E, PAR, Ls, SPAD, and LAI increased and then decreased with enhanced fertilization, and their maximum values appeared in the A2B2 treatment. The Ci and WUE decreased and then increased with enhanced fertilization, and their minimum values appeared in the A2B2 treatment. Our results suggested that fertilization had significant effects on the leaf photosynthetic capacity and grain yield of tartary buckwheat
Yunqiao1, and the best fertilization strategy was 450 kg ha-1 with NPK 1:4:2., C. Wang, H. Z. She, X. B. Liu, D. Hu, R. W. Ruan, M. B. Shao, L. Y. Zhang, L. B. Zhou, G. B. Zhang, D. Q. Wu, Z. L. Yi., and Obsahuje bibliografii