盐度是作物生产的主要制约因素之一。水稻是主要主食,对盐度高度敏感。本研究旨在阐明盐胁迫对不同耐盐性基因型水稻生理和农艺性状的影响。六种不同的水稻基因型(DJWJ,JFX,NSIC,HKN,XD2H和HHZ),包括三个耐盐和三个盐敏感水稻基因型,在两种不同的盐浓度(0和100mmolL-1NaCl溶液)下生长。结果表明,生长,盐胁迫对盐敏感和耐盐水稻的生理和产量相关性状均有显著影响。总的来说,植物高度,舵柄编号,干重和相对生长率为15.7%,11.2%,盐敏感水稻比耐盐水稻减少25.2%和24.6%,分别。相反,抗氧化酶活性(超氧化物歧化酶,过氧化物酶,过氧化氢酶),渗透调节物质(脯氨酸,可溶性蛋白质,盐胁迫下丙二醛(MDA)和Na+含量显著增加,除MDA外,耐盐水稻的增幅高得多。此外,盐胁迫下籽粒产量和产量构成显著下降。总的来说,盐敏感型水稻基因型显示谷物产量减少15.3%,每穗小穗减少5.1%,与盐胁迫下的耐盐基因型相比,籽粒灌浆率降低了7.4%,籽粒重量降低了6.1%。然而,一个适度的差距显示圆锥花序下降(22.2%与22.8%)和总小穗(45.4%与42.1%)在盐分条件下对盐敏感和耐盐水稻之间。这项研究表明,耐盐水稻的产量优势部分是由更多的生物量积累引起的,增长率,在盐胁迫下具有较强的抗氧化能力和渗透调节能力,这导致了更多的小穗,高的籽粒填充率和粒重。本研究的结果有助于理解水稻基因型对盐胁迫的反应和耐盐水稻育种的生理机制。
Salinity is one of the major constraints to crop production. Rice is a main staple food and is highly sensitive to salinity. This study aimed to elucidate the effects of salt stress on physiological and agronomic traits of rice genotypes with contrasting salt tolerance. Six contrasting rice genotypes (DJWJ, JFX, NSIC, HKN, XD2H and HHZ), including three salt-tolerant and three salt-sensitive rice genotypes, were grown under two different salt concentrations (0 and 100 mmol L-1 NaCl solution). The results showed that growth, physiological and yield-related traits of both salt-sensitive and salt-tolerant rice were significantly affected by salt stress. In general, plant height, tiller number, dry weight and relative growth rate showed 15.7%, 11.2%, 25.2% and 24.6% more reduction in salt-sensitive rice than in salt-tolerant rice, respectively. On the contrary, antioxidant enzyme activity (superoxide dismutase, peroxidase, catalase), osmotic adjustment substances (proline, soluble protein, malondialdehyde (MDA)) and Na+ content were significantly increased under salt stress, and the increase was far higher in salt-tolerant rice except for MDA. Furthermore, grain yield and yield components significantly decreased under salt stress. Overall, the salt-sensitive rice genotypes showed a 15.3% greater reduction in grain yield, 5.1% reduction in spikelets per panicle, 7.4% reduction in grain-filling percentage and 6.1% reduction in grain weight compared to salt-tolerant genotypes under salt stress. However, a modest gap showed a decline in panicles (22.2% vs. 22.8%) and total spikelets (45.4% vs. 42.1%) between salt-sensitive and salt-tolerant rice under salinity conditions. This study revealed that the yield advantage of salt-tolerant rice was partially caused by more biomass accumulation, growth rate, strong antioxidant capacity and osmotic adjustment ability under salt stress, which contributed to more spikelets per panicle, high grain-filling percentage and grain weight. The results of this study could be helpful in understanding the physiological mechanism of contrasting rice genotypes\' responses to salt stress and to the breeding of salt-tolerant rice.