Journal of Plant Process and Function

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To understand the agrophysiological barley associated with flag leaf temperature and canopy light interception under salinity and zinc foliar application (ZnFA), a field experiment was conducted in a strip-plot design with three replications in Isfahan, Iran. Saline irrigation water in three levels [2 (low), 10 (moderate) and 18 (high) dS m^-1] were applied as vertical factors. Three barley genotypes [‘Morocco’ (salt-sensitive), ‘Nosrat’ (semi-salt-tolerant) and ‘Khatam’ (salt-tolerant)] were arranged within the vertical factors. The horizontal factors were four ZnFA [Nano-ZnO, Zn-EDTA, simultaneous applications of (Nano-ZnO + Zn-EDTA), and water (control)]. With increasing  salinity, light interception (LI), maximal efficiency of PSII (Fv/Fm), chlorophyll content (SPAD), relative water content (RWC),  number of spike (NS), kernel number per spike (KNS), thousand-kernel weight (TKW), and grain yield (GY) decreased, but electrolyte leakage (EL), flag leaf temperature (FLT) and proline  increased. Nano-ZnO had the highest EL and the lowest FLT, RWC, NS and KNS. Zn-EDTA application provided the highest LI, RWC, TKW and GY, and the lowest proline. Minus zinc application (check) had minimum LI, Fv/Fm, SPAD and GY. The tolerant genotype had maximum LI, proline, SPAD, RWC, KNS and GY, and minimum FLT, EL, NS and TKW. Overall, it was concluded that Zn-EDTA can be as a proper tool for increasing barley yield under salinity stress conditions. Likewise, this study has highlighted the close relationships existing between GY with, TKW (r= 0.89**), KNS (r= 0.46**), RWC (0.45**), NS (r= 0.36**), FLT (r= -0.32**), EL (r= -0.21**), and SPAD (r= 0.20**). These findings indicated that these physiological traits could be key factors, tools for screening, and provide useful information about stress tolerance mechanisms, which could be useful to plant breeders for selecting and developing salt-tolerant genotypes.

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To evaluate the effect of salinity stress and Zinc application on grain filling of three barley cultivars and some physiological traits this this experiment was arranged as a split block in a randomized complete block design with three replications at the Esfahan (Rodasht) salinity research station (2013-14). Three water quality treatments including (2, 10 and 18 dS/m) were evaluated in vertical factors. The horizontal factors were foliar spraying including (nano zinc-oxide, chelated zinc, mixture of nano and chelated zinc and water spraying as a control). Three different barley cultivars including (Morocco, Nosrat and Khatam) spilted within vertical factors. The results showed that with increasing salinity irrigation water, grain filling period, minimum and maximum fluorescence and maximum grain weight decreased, and eventually the grain yield decreased. To moderate salinity (10 ds/m), foliar application of Zinc fertilizer in all experimental cultivars increased grain yield. Khatam cultivar had the highest chlorophyll index (46.7), minimum (61.9) and maximum fluorescence (314.2) and maximum grain weight (0.0367 gr). At high salinity, Zinc application was produced the lowest amount of proline by Nosrat (141.4 μmole/g) and Khatam (201.8 μmole/g) cultivars.
With increasing salinity, Zinc application was produced high amount of peroxidase anzyme at Nosrat and Khatam cultivars. At high salinity, grain yield was related to cultivar and kind of Zinc fertilizer. At this salinity level, foliar application with Zinc was reduced grain yield of Morocco cultivar but, foliar application of zinc chelate in Khatam cultivar (2622.7 kg/ha) and Nosrat cultivar (2454.7 kg/ha) had the highest grain yield. It seems that the use of zinc element under salinity stress conditions increased plant tolerance to stress by increasing grain-filling rate, grain-filling duration, maximum grain weight and peroxidase enzyme content. As a result, the plantchr('39')s tolerance to stress increase reduces the amount of proline and ultimately increases grain yield.