Mao Bing, Wang Yan, Zhao Tian-Hong, Tian Rong-Rong, Wang Wei, Ye Jia-Shu
Postdoctoral Research Station of Crop Science, College of Agronomy, Shenyang Agricultural UniversityShenyang, China.
College of Agronomy, Shenyang Agricultural UniversityShenyang, China.
Front Plant Sci. 2017 Sep 11;8:1568. doi: 10.3389/fpls.2017.01568. eCollection 2017.
Enhanced ultraviolet-B (UV-B) radiation and elevated tropospheric ozone alone may inhibit the growth of agricultural crops. However, research regarding their combined effects on growth and biochemical properties of roots is still scarce. Using open top chambers, we monitored the response of growth, secondary metabolites, endogenous hormones and enzyme activities of soybean roots to elevated O and enhanced UV-B individually and in combination at stages of branching, flowering and podding. Our results indicated that the root biomass decreased by 23.6, 25.2, and 27.7%, and root oxidative capacity declined by11.2, 39.9, and 55.7% exposed to elevated O, enhanced UV-B, and O + UV-B, respectively, compared to the control treatment. Concentrations of quercetin and ABA were significantly increased, while concentrations of total polyphenol and P-coumaric acid responded insignificantly to elevated O, enhanced UV-B, and O + UV-B during the whole period of soybean growth. Elevated O, enhanced UV-B and O + UV-B showed significant negative effects on superoxide dismutase (EC 1.15.1.1) activity at flowering stage, on activities of peroxidase (EC 1.11.1.7) and catalase (EC 1.11.1.6) at podding stage, on ascorbate peroxidase activity during the whole period of soybean growth. Moreover, compared to hormones and enzyme activity, secondary metabolisms showed stronger correlation with root growth exposed to elevated O and enhanced UV-B individually and in combination. Our study concluded that combined effects of O and UV-B radiation significantly exacerbated the decline of soybean root growth, and for annual legumes, the inhibited root growth exposed to O and/or UV-B radiation was mostly associated with secondary metabolisms (especially flavonoids).
单独的增强型紫外线B（UV-B）辐射和对流层臭氧浓度升高可能会抑制农作物生长。然而，关于它们对根系生长和生化特性的综合影响的研究仍然很少。我们使用开顶式气室，监测了大豆根系在分枝期、开花期和结荚期对臭氧浓度升高、增强型UV-B单独作用以及二者联合作用下的生长、次生代谢产物、内源激素和酶活性的响应。我们的结果表明，与对照处理相比，暴露于臭氧浓度升高、增强型UV-B以及臭氧+UV-B条件下，根生物量分别下降了23.6%、25.2%和27.7%，根系氧化能力分别下降了11.2%、39.9%和55.7%。在大豆生长的整个时期，槲皮素和脱落酸（ABA）的浓度显著增加，而总多酚和对香豆酸的浓度对臭氧浓度升高、增强型UV-B以及臭氧+UV-B的响应不显著。臭氧浓度升高、增强型UV-B以及臭氧+UV-B对开花期的超氧化物歧化酶（EC 1.15.1.1）活性、结荚期的过氧化物酶（EC 1.11.1.7）和过氧化氢酶（EC 1.11.1.6）活性以及大豆生长整个时期的抗坏血酸过氧化物酶活性均有显著负面影响。此外，与激素和酶活性相比，次生代谢与单独或联合暴露于臭氧浓度升高和增强型UV-B条件下的根系生长具有更强的相关性。我们的研究得出结论，臭氧和UV-B辐射的联合作用显著加剧了大豆根系生长的下降，对于一年生豆科植物，暴露于臭氧和/或UV-B辐射下根系生长受到抑制主要与次生代谢（尤其是黄酮类化合物）有关。
