摘要
为探讨UV-B辐射对稻田土壤碳转化和温室气体排放的影响,采用元阳梯田稻田土并种植当地传统水稻(Oryza sativa L.)品种白脚老粳,开展室内根袋培养试验,研究UV-B辐射对水稻根际及非根际土壤有机酸与活性有机碳含量、酶活性和产甲烷潜力的影响。结果表明:(1)与自然光照相比,UV-B辐射导致水稻根际土壤草酸和琥珀酸含量显著增加,增幅分别为18.8%—43.2%和13.9%—48.7%,根际土壤苹果酸和酒石酸含量显著下降,最大降幅分别为50.1%和69.9%;(2)UV-B辐射使根际土壤多酚氧化酶活性提高,自然光和UV-B辐射条件下非根际土壤蔗糖酶活性和过氧化氢酶活性显著低于根际土壤;(3)UV-B辐射处理下水稻非根际土壤活性有机碳(溶解性有机碳、易氧化有机碳和微生物量碳)含量与根际相比显著降低,与自然光照相比,UV-B辐射使水稻根际微生物量碳和溶解性有机碳含量分别显著提高49.9%和55.7%,而CH4排放量显著降低56%;(4)相关性分析发现,苹果酸与微生物量碳(r=0.791**,P<0.01)和可溶性有机碳(r=0.534*,P<0.05)呈显著正相关,过氧化氢酶与有机碳呈显著负相关,且可溶性有机碳(r=−0.907*,P<0.05)、易氧化有机碳(r=−0.884*,P<0.05)含量与甲烷排放通量呈显著负相关,微生物量碳(r=−0.930**)与甲烷排放通量呈极显著负相关(P<0.01)。UV-B辐射下,根际土壤有机酸含量、活性有机碳含量及碳转化酶活性均显著高于非根际土壤,水稻根际土壤甲烷排放通量显著低于自然光,可见,UV-B辐射通过水稻根际有机酸、稻田土壤碳转化酶活性改变有机碳含量,进而间接影响稻田温室气体排放。
To investigate the effects of UV-B radiation on soil carbon conversion and greenhouse gas emissions in paddy soil.The rice paddy soil was sampled from Yuanyang terraced field and a local traditional rice(Oryza sativa L.)cultivar Baijiaolaojing was planted in an indoor rhizo-bag experiment.The effects of UV-B radiation on the contents of organic acid and activated organic carbon,enzyme activity and methane production potential of rice rhizosphere and non-rhizosphere soil were investigated.The results showed that:(1)Compared with natural light,UV-B radiation significantly increased the contents of oxalic acid and succinic acid in rice rhizosphere soil by 18.8%‒43.2%and 13.9%‒48.7%,respectively,and decreased the contents of malic acid and tartaric acid by 50.1%and 69.9%,respectively.(2)UV-B radiation increased the activity of polyphenol oxidase in rhizosphere soil,while the activity of sucrase and catalase in non-rhizosphere soil under natural light and UV-B irradiation was significantly lower than that in rhizosphere soil.(3)Under UV-B radiation,the content of active organic carbon(i.e.,soluble organic carbon,readily oxidized organic carbon,and microbial biomass carbon)in non-rhizosphere soil of rice was significantly lower than that in rhizosphere soil.Compared with natural light,UV-B radiation significantly increased rice rhizosphere microbial biomass carbon and dissolved organic carbon content by 49.9%and 55.7%,respectively,and the CH4 emissions significantly decreased by 56%.(4)Correlation analyses showed that malic acid was significantly positively correlated with microbial biomass carbon(r=0.791*,P<0.01)and soluble organic carbon(r=0.534*,P<0.05);catalase was significantly negatively correlated with organic carbon;soluble organic carbon(r=−0.907*,P<0.05)and readily oxidized organic carbon(r=−0.884*,P<0.05)were significantly negatively correlated with methane emission flux;and microbial biomass carbon was significantly negatively correlated with methane emission flux(r=−0.930**,P<0.01).With the treatment of UV-B radiation,the content of rhizosphere soil organic acids(i.e.,oxalic acid,succinic acid,malic acid,and tartaric acid),the activity of carbon invertase(i.e.,polyphenol oxidase,sucrase,and catalase),and the content of active organic carbon(i.e.,microbial biomass carbon,soluble organic carbon,and readily oxidized organic carbon)were significantly higher than that in non-rhizosphere soil.The methane emission flux of the rice rhizosphere soil under UV-B radiation was significantly lower than that under natural light,indicating that UV-B radiation changes the content of organic carbon through organic acids in rice rhizosphere and carbon invertase activities in paddy soil,and then indirectly affects greenhouse gas emissions in the paddy field.
作者
贺晓佳
冯书华
蒋明
李明锐
湛方栋
李元
何永美
HE Xiaojia;FENG Shuhua;JIANG Ming;LI Mingrui;ZHAN Fangdong;LI Yuan;HE Yongmei(College of Resources and Environment,Yunnan Agricultural University,Kunming 650201,P.R.China)
出处
《生态环境学报》
CSCD
北大核心
2022年第3期556-564,共9页
Ecology and Environmental Sciences
基金
国家自然科学基金项目(32060287
31760113)。