The Combined Effects of Nitric Oxide and Thiourea on Plant Growth and Mineral Nutrition of Salt-Stressed Plants of Two Maize Cultivars with Differential Salt Tolerance (Retraction of Vol 42, Pg 1, 2016)

摘要

The combined effects of exogenously-applied nitric oxide (NO) and thiourea (TU) on plant growth and mineral nutrition of salt-stressed plants of two maize cultivars (DK 5783 and Apex 836) were studied under greenhouse conditions. The caryopses of the two cultivars were sown in pots containing soil salinized with 0 or 100 mM sodium chloride (NaCI) applied through irrigation water. In some other experiments, the effectiveness of NO and TU in growth regulation in salt-stressed plants was examined individually and both were found to be partially effective in mitigating the hazardous effects of salt on plants. So in the present study, of six NO and TU levels used in the initial germination experiment, 2 levels of combined NO and TU (3 + 400 or 6 + 500 mg L-1) applied as seed soaking (pre-sowing) or as a spray to the leaves of 10-day old seedlings were chosen for subsequent studies. The experiment was placed in a randomized complete block design replicated thrice. Salinity stress resulted in high reductions in plant fresh and dry matters, total chlorophyll and maximum fluorescence yield (FvJFm), but increase in proline content and membrane permeability (MP) in both cultivars. The earlier mentioned reductions were greater in cv. Apex 836 than those in cv. DK 5783. In contrast, increase in proline contents under saline regime was higher in salt tolerant cultivar DK 5783 than that in salt sensitive cultivar Apex 836. Both treatments of combined NO and TU as seed soaking or foliar application were more effective in mitigating salt-induced shoot growth inhibition. Seed treatment with both levels of combined NO and TU was more effective in improving dry weights of cv. DK 5783 than that with foliar treatments. Salt stress enhanced leaf sodium (Na+) contents, but reduced those of potassium (K+) and calcium (Ca2+) in both cultivars. Both modes of treatment of combined growth substances resulted in increased Ca2+ and K+ contents, whereas decreased Na+ in salt-stressed plants. From these findings it is evident thatexogenously-applied NO and TU caused growth improvement in maize plants which was ascribed to reduced MP under saline environment. It can be concluded that NO and TU may be involved in nutritional and physiological changes in plants subjected to high salinity.