Calligonum caput-medusae is known to grow well when irrigated with water containing NaCl. The aim of this study was to investigate ecophysiological responses of C. caput-medusae to different NaCl concentrations. In our study, we examined the effect of 0, 50, 100, 200, and 400 mM NaCl. Our results demonstrated that maximum seedling growth occurred at 50 mM NaCl. Photosynthetic parameters, such as the photosynthetic pigment content and gas exchange parameters, correlated with growth response. High salinity (≥ 100 mM NaCl) resulted in a significant reduction of the plant growth. Similarly, marked declines in the pigment content, maximal efficiency of PSII photochemistry, net photosynthetic rate, transpiration rate, and stomatal conductance were also detected. However, intercellular CO2 concentration showed a biphasic response, decreasing with water containing less than 200 mM NaCl and increasing with NaCl concentration up to 400 mM. Water-use efficiency and intrinsic water-use efficiency exhibited the opposite response. The reduction of photosynthesis at the high NaCl concentration could be caused by nonstomatal factors. High salinity led also to a decrease in the relative water content and water potential. Correspondingly, an accumulation of soluble sugars and proline was also observed. Na+ and
Cl- concentrations increased in all tissues and K+ concentrations were maintained high during exposure to NaCl compared with the control. High salinity caused oxidative stress, which was evidenced by high malondialdehyde and hydrogen peroxide contents. In order to cope with oxidative stress, the activity of antioxidative enzymes increased to maximum after 50 mM NaCl treatment. The data reported in this study indicate that C. caput-medusae can be utilized in mild salinity-prone environments., Y. Lu, J.-Q. Lei, F.-J. Zeng, B. Zhang, G.-J. Liu, B. Liu, X.-Y. Li., and Obsahuje bibliografii
Salt stress is one of the most critical factors hindering the growth and development of plants. Paclobutrazol (PBZ) is widely used to minimize this problem in agriculture because it can induce salt stress tolerance in plants. This study investigated the effects of PBZ on salt tolerance of seedlings from two Chinese bayberry cultivars (i.e., Wangdao and Shenhong). Plants were treated with three salt concentrations (0, 0.2, and 0.4 % NaCl) and two PBZ concentrations (0 and 2.0 μmol L-1). Application of PBZ increased a relative water content, proline content, chlorophyll (a+b) content, and antioxidant enzyme activities in both cultivars, resulting in a better acclimation to salt stress and an increase in dry matter production. We concluded that PBZ ameliorated the negative effects of salt stress in Chinese bayberry seedlings., Y. Hu, W. Yu, T. Liu, M. Shafi, L. Song, X. Du, X. Huang, Y. Yue, J. Wu., and Obsahuje bibliografii
The effect of salinity on some morpho-physiological characteristics in lisianthus cultivars was investigated. Cultivars namely, Blue Picotee (C1), Champagne (C2), Lime Green (C3), and Pure White (C4), were subjected to salt stress (0-60 mM NaCl) in a sand culture and their responses were measured. Our results showed that as a salinity level increased, growth parameters, relative water content, photosynthetic pigments, and gas-exchange characteristics decreased in all cultivars, while root fresh mass, root/shoot length ratio, electrolyte leakage, and a malondialdehyde content increased. However, the changes were less pronounced in C3 and C4 compared to C1 and C2. The regression analysis of the relationship between salinity levels and seedling height or root/shoot length ratio defined two groups with different slope coefficients: C1 and C2 as salt-sensitive cultivars and C3 and C4 as salt-tolerant cultivars. Shoot dry mass and leaf area tolerance indices were less affected by salinity in C3 and C4 compared to those in C1 and C2. Further, C3 and C4 showed higher photosynthetic rates, greater stomatal conductances, and accumulated greater K+ and Ca2+ contents and K+/Na+ ratios in roots and shoots compared to those in C1 and C2. The results suggests that C3 and C4 could be recommended as resistant cultivars due to maintaining higher growth, water balance, leaf gas exchange, ion compartmentalization, and lower lipid peroxidation in response to salinity compared to C1 and C2., N. Ashrafi, A. Rezaei Nejad., and Obsahuje bibliografii
Physiological responses of two wheat (Triticum aestivum L.) genotypes (salt-tolerant DK961 and salt-sensitive JN17) to increased salt concentrations (50, 100, 150 mM NaCl: NaCl50, NaCl100, NaCl150) were studied. Photosynthetic capacity, irradiance response curves, contents of soluble sugars, proteins, and chlorophyll (Chl), K+/Na+ ratio, and activities of antioxidant enzymes (superoxide dismutase, peroxidase, and catalase) in flag leaves were measured on 7 d after anthesis. In control (NaCl0) plants, non-significant (p>0.05) differences were found in gas exchange and saturation irradiance (SI) between salt-tolerant (ST) and salt-sensitive (SS) wheat genotypes. However, we found higher soluble sugar and protein contents, K+/Na+ ratio, and antioxidant enzyme activities, but lower Chl content and yield in ST wheat. Salinity stresses remarkably increased soluble sugar and protein contents and the antioxidant activities, but decreased K+/Na+ ratio, Chl contents, SI, photosynthetic capacities, and yield, the extent being considerably larger in JN17 than DK961. Although the soluble sugar and protein contents and the antioxidant activities of JN17 elevated more evidently under salt stresses, those variables never reached the high levels of DK961. The antioxidant enzyme activities of SS wheat increased in NaCl50 and NaCl100, but decreased rapidly when the NaCl concentration reached 150 mM. Thus the ST wheat could maintain higher grain yield than the SS one by remaining higher osmoregulation and antioxidative abilities, which led to higher photosynthetic capacity. Hence the ST wheat could harmonize the relationship between CO2 assimilation (source) and the grain yield (sink) under the experimental conditions. and Y. H. Zheng ... [et al.].