Abstract:Two-year old seedlings of Silver buffaloberry (Shepherdia argentea (Pursh) Nutt.) were exposed to NaCl salinity (0, 200, 400 and 600 mmol/l) for 30 days. Leaf water potential (Ψ w ), chlorophyll contents (Chl a, b, and a + b) and K + content decreased with an increase in salinity. Relative water content (RWC) declined significantly with 400 and 600 mmol/l NaCl. However, salinity induced an excessive accumulation of Na + in the leaves of plants. Light responses of photosynthesis showed that net photosynthetic r… Show more
“…Differences (p < 0.05) were obtained for Chl-a and total chlorophylls, values decreasing when soil salinity content increases, but no differences in the Chl-b content were found. Previous studies also reported that Chl-b was less sensitive to salt stress than Chl-a (Naumann et al, 2008;Qin et al, 2010). However, no correlation was found between chlorophylls and the NDVI indices used in this work thus indicating that levels of chlorophyll were not the only parameter affecting NDVI indices.…”
). Spectral data of leaves were transformed into vegetation indices indicative of the physiological status of the plants. The results showed differences for N (p < 0.05), K and Na content (p < 0.01) due to salinity suggesting different degrees of salt stress on the plants. Specific leaf area increased with salinity levels (p < 0.001). The capabilities of VNIR radiometry to assess the influence of soil salinity on melon physiology using a non-destructive method were demonstrated. A normalized difference vegetation index , and the ratio between water index (WI) and normalized difference vegetation index (WI/NDVI 750-705 ) showed significant relationships (p < 0.01) with the salinity. Therefore, this method could be used for in-situ early detection of salinity stress effects.
“…Differences (p < 0.05) were obtained for Chl-a and total chlorophylls, values decreasing when soil salinity content increases, but no differences in the Chl-b content were found. Previous studies also reported that Chl-b was less sensitive to salt stress than Chl-a (Naumann et al, 2008;Qin et al, 2010). However, no correlation was found between chlorophylls and the NDVI indices used in this work thus indicating that levels of chlorophyll were not the only parameter affecting NDVI indices.…”
). Spectral data of leaves were transformed into vegetation indices indicative of the physiological status of the plants. The results showed differences for N (p < 0.05), K and Na content (p < 0.01) due to salinity suggesting different degrees of salt stress on the plants. Specific leaf area increased with salinity levels (p < 0.001). The capabilities of VNIR radiometry to assess the influence of soil salinity on melon physiology using a non-destructive method were demonstrated. A normalized difference vegetation index , and the ratio between water index (WI) and normalized difference vegetation index (WI/NDVI 750-705 ) showed significant relationships (p < 0.01) with the salinity. Therefore, this method could be used for in-situ early detection of salinity stress effects.
“…When salt stress becomes severe and CO 2 assimilation is significantly disturbed, the role of nonstomatal factors in the limitation of photosynthesis usually becomes more pronounced (Brugnoli and Lauteri 1991;Qin et al 2010). As can be seen in Fig.…”
The photosynthetic responses to salt stress were examined in a wheat (Triticum aestivum L. cv. Asakaze) -barley (Hordeum vulgare L. cv. Manas) 7H addition line having elevated salt tolerance as compared to the parental wheat genotype. For this purpose, increasing NaCl concentrations up to 300 mM were applied and followed by a 7-day recovery period. Up to moderate salt stress (200 mM NaCl), forcible stomatal closure, parallel with a reduction in the net assimilation rate (P N ), was only observed in wheat, but not in the addition line or barley. Since the photosynthetic electron transport processes of wheat were not affected by NaCl, the impairment in P N could largely be accounted for the saltinduced decline in stomatal conductance (g s ), accompanied by depressed intercellular CO 2 concentration and carboxylation efficiency. Both, P N and nonstomatal limitation factors (L ns ) were practically unaffected by moderate salt stress in barley and in the addition line due to the sustained g s , which might be an efficient strategy to maintain the efficient photosynthetic activity and biomass production. At 300mM NaCl, both P N and g s decreased significantly in all the genotypes, but the changes in P N and L ns in the 7H addition line were more favourable similar to those in wheat. The downregulation of photosynthetic electron transport processes around PSII, accompanied by increases in the quantum yield of regulated energy dissipation and of the donor side limitation of PSI without damage to PSII, was observed in the addition line and barley during severe stress. Incomplete recovery of P N was observed in the addition line as a result of declined PSII activity probably caused by enhanced cyclic electron flow around PSI. These results suggest that the better photosynthetic tolerance to moderate salt stress of barley can be manifested in the 7H addition line which may be a suitable candidate for improving salt tolerance of wheat.Additional key words: chlorophyll fluorescence induction; improved salt tolerance; leaf gas exchange; recovery; wheat-barley addition.
---Received 25 January 2016, accepted 5 May 2016. + Corresponding author; e-mail: ds@ektf.hu Abbreviations: 7H add -wheat-barley 7H addition line; CEF -cyclic electron flow around PSI; Ci -intercellular CO2 concentration; F -steady-state fluorescence; F0, Fm -minimum and maximum Chl fluorescence determined in the dark-adapted state; Fm' -maximal fluorescence in the light-adapted state; Fv -variable fluorescence; Fv/Fm -maximum quantum yield of PSII photochemistry; gs -stomatal conductance; Lns -nonstomatal limitation; Ls -stomatal limitation; NPQ -nonphotochemical quenching; P0 -minimal P700 signal; Pm -maximal P700 level; Pm' -maximal P700 signal in a given light state; PN -net assimilation rate; PNmax -maximal assimilation rate; RuBP -ribulose-1,5-bisphosphate; RWC -relative water content; ε -carboxylation efficiency; ɸCEF -quantum yield of cyclic electron flow around PSI; ɸNA -quantum yield of the acceptor side limitation of PSI; ɸND -quantum yield o...
“…Water status is a major factor affecting plant growth and development. A decrease of the leaf relative water content under saline conditions has been observed frequently (Qin et al, 2010;Aroca et al, 2012). The decrease of water uptake under salt stress conditions could be a strategy to diminish the water flow from the roots to the soil while the soil osmotic potential is lower than that of the roots.…”
Section: Leaf Relative Water Content Capacitymentioning
Abstract. The salt tolerance of crop species and cultivars may vary depending on the mineral content of the soil. Phosphorus (P) availability and uptake is limited in calcareous soil. The main problem of salinity and P deficiency is reduced yield in arid and semiarid regions. To examine the relations between NaClsalinity (0, 50 mM, 100 mM and 150 mm) and P (0, 30, 60 and 90 kg P 2 O 5 ha -1 stated P 0 , P 30 , P 60 and P 90 , respectively) on growth, water potential, chlorophyll and P concentration of green beans, a pot experiment was conducted for thirty days in a climate chamber. The experiment was designed as a complete randomized block with three replicates. Salinity decreased dry matter and P concentrations of root, stem and leaf as well as the chlorophyll content of old leaves, while P application increased dry weight and the P concentration of plants. Chlorophyll content of young leaves was increased by P application and P 60 with 50 mM application led to a reduction of water loss in turgor when compared to control. The results of this study suggested that dry weight and P concentration in green bean leaves were affected positively by P 60 together with 50 mM NaCl application. In addition, the same application decreased the loss of turgidity of younger leaves. The adequate P application may have contributed to the water potential of green beans under salinization.
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