Ji Rongting, Min Ju, Wang Yuan, Kronzucker Herbert J, Shi Weiming
Nanjing Institute of Environmental Sciences, Ministry of Ecology and Environment of the People's Republic of China, Nanjing, China.
State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China.
Front Plant Sci. 2022 Apr 8;13:864285. doi: 10.3389/fpls.2022.864285. eCollection 2022.
Plant growth regulators are known to exert strong influences on plant performance under abiotic stress, including exposure to high nitrate, as occurs commonly in intensive vegetable production. However, direct comparative evaluations of growth regulators under otherwise identical conditions in major crop species are scarce. In this study, tomato ( L.) was used as a model crop, and the roles of four common exogenously applied plant growth regulators (MT, melatonin; SA, salicylic acid; HA, humic acid; SNP, sodium nitroprusside) in regulating crop growth were studied under high-nitrate stress. We provide a particular focus on root system architecture and root physiological responses. Our data show that all four growth regulators improve tomato tolerance under high nitrate, but that this occurs to differing extents and via differing mechanisms. Optimal concentrations of MT, SA, HA, and SNP were 50 μmol L, 25 μmol L, 25 mg L, and 50 μmol L, respectively. MT and SNP produced the strongest effects. MT enhanced root growth while SNP enhanced above-ground growth. Growth of coarse and thin lateral roots was significantly improved. Furthermore, an enhancement of root vitality and metabolism, improved integrity of root cell membranes, and an increase in antioxidant enzyme activities were found, but regulatory mechanisms were different for each growth regulator. Our results show that in particular the application of MT and SNP can improve growth of tomato in intensive vegetable production under high-nitrate stress and that root growth stimulation is of special importance in procuring these beneficial effects.
植物生长调节剂已知在非生物胁迫下对植物性能有强烈影响，包括暴露于高硝酸盐环境，这在集约化蔬菜生产中很常见。然而，在主要作物物种的相同条件下对生长调节剂进行直接比较评估的研究很少。在本研究中，以番茄（L.）作为模式作物，研究了四种常见的外源施用植物生长调节剂（MT，褪黑素；SA，水杨酸；HA，腐殖酸；SNP，硝普钠）在高硝酸盐胁迫下对作物生长的调节作用。我们特别关注根系结构和根系生理反应。我们的数据表明，所有四种生长调节剂都能提高番茄在高硝酸盐环境下的耐受性，但程度不同且机制各异。MT、SA、HA和SNP的最佳浓度分别为50 μmol L、25 μmol L、25 mg L和50 μmol L。MT和SNP的效果最强。MT促进根系生长，而SNP促进地上部生长。粗细侧根的生长均显著改善。此外，还发现根系活力和代谢增强、根细胞膜完整性提高以及抗氧化酶活性增加，但每种生长调节剂的调控机制不同。我们的结果表明，特别是MT和SNP的应用可以改善集约化蔬菜生产中高硝酸盐胁迫下番茄的生长，并且刺激根系生长在获得这些有益效果方面尤为重要。
