UV-B辐射和施氮对满江红生长、矿质营养和抗氧化生理的影响

Effects of UV-B radiation and nitrogen application on the growth,mineral nutrition,and antioxidant physiology of Azolla

为探讨UV-B辐射和施氮对满江红(Azolla)生长、矿质营养和抗氧化生理的影响,以元阳梯田稻田满江红为材料,室内模拟UV-B辐射(0 kJ·m^(-2)与5.0 kJ·m^(-2))和施N处理(无氮和0.06 g·L^(-1)氮),研究其对满江红生长、矿质营养和抗氧化生理的影响。结果表明,与CK(0 kJ·m^(-2)、无氮)相比,UV-B+N(5.0 kJ·m^(-2)、0.06 g·L^(-1)氮)、UV-B辐射(5.0 kJ·m^(-2)、无氮)处理均显著降低满江红光合色素含量,抑制其生长,导致生物量显著下降。UV-B辐射与施N单独或复合处理均显著增加满江红的N含量与累积量,降低植株Mg、Ca的含量。UV-B辐射与施N单独或复合处理均显著增加满江红丙二醛(MDA)含量,提高超氧化物歧化酶(SOD)、谷胱甘肽还原酶(GR)活性,降低类黄酮含量和过氧化物酶(POD)活性。此外,UV-B辐射导致满江红抗坏血酸(AsA)含量下降、总酚含量增加,UV-B辐射与N处理显著增强满江红的总抗氧化能力。相关性分析发现,类黄酮、类胡萝卜素含量与生物量呈显著正相关。双因素分析表明,UV-B辐射显著增加了满江红氮、总酚、MDA含量,提高SOD、GR活性与总抗氧化能力;N处理显著增加AsA、MDA含量及SOD、GR活性;UV-B+N处理对满江红的生长系数、生物量、磷、钙、镁、叶绿素a、类胡萝卜素、AsA、总酚和类黄酮含量及POD、SOD活性和总抗氧化能力的影响存在交互作用。综上,UV-B辐射增强会抑制满江红生长,导致满江红N含量与累积量增加,施氮不能缓解UV-B辐射对满江红生长的抑制效应。

To investigate the effects of UV-B radiation and nitrogen(N)application on the growth,mineral nutrition,and antioxidant physiology of Azolla imbricata,an indoor experiment was conducted using A.imbricata from Yuanyang terrace under enhanced UV-B radiation(0 and 5.0 kJ·m^(-2))and N application(no N and 0.06 g·L^(-1) ammonia N)treatments.The results showed that compared with CK(0 kJ·m^(-2),no N),UV-B+N(5.0 kJ·m^(-2),0.06 g·L^(-1) ammonia N)and UV-B radiation(5.0 kJ·m^(-2),no N)significantly reduced the content of photosynthetic pigments,inhibited the growth,and significantly decreased the biomass of Azolla.UV-B radiation and N application alone or in combination significantly increased the N content and accumulation,and decreased the content of magnesium and calcium in Azolla compared with CK.UV-B radiation and N application alone or in combination significantly increased the malondialdehyde(MDA)content,increased superoxide dismutase(SOD)and glutathione reductase(GR)activities,and decreased the flavonoid content and peroxidase(POD)activity compared with CK.In addition,UV-B radiation decreased the ascorbic acid(AsA)content and increased the total phenol content,and UV-B radiation and N application significantly increased the total antioxidant capacity of Azolla compared with CK.The correlation analysis indicated that the content of flavonoids,and carotenoids significantly positively correlated with the biomass.A two factor analysis indicated that UV-B radiation significantly increased the N,total phenol,and MDA content,and total antioxidant capacity,and enhanced the SOD and GR activities.N application significantly increased the content of AsA and MDA and the activities of SOD and GR compared with CK.The UV-B+N treatment influenced the growth coefficient;biomass;the content of phosphorus,calcium,magnesium,chlorophyll a,carotenoid,AsA,total phenols,and flavonoids;activities of POD and SOD;and total antioxidant capacity of Azolla.In conclusion,UV-B irradiation inhibited the growth of Azolla,resulting in an increase in the N content and accumulation,and N application did not alleviate the inhibitory effect of UV-B irradiation on the growth of Azolla.