【作者】 王伟；

【导师】 赵天宏；

【作者基本信息】 沈阳农业大学 ， 生态学， 2017， 硕士

【摘要】 增强UV-B辐射会抑制植物光合特性,破坏植株细胞膜,对膜系统等生物机体结构造成伤害。适宜浓度的镧能提高细胞膜的保护功能,增强植物对不良环境的抵抗能力。素有"牧草之王"的紫花苜蓿,是优良的豆科牧草,在中国乃至世界广泛种植。本文以紫花苜蓿为试验材料,采用样方法条播与叶面喷施方式,研究UV-B辐射增强(5%和10%)下,在不同生育期(分枝期、初花期)喷施氯化镧(30、60和90 mg·L-1)对紫花苜蓿生理特性的影响。结果表明:在UV-B辐射增强5%时,分枝期氯化镧处理后,在初花期,30 mg·L-1处理下紫花苜蓿净光合速率(Pn)、PSⅡ最大光化学量子产量(Fv/Fm)、超氧阴离子自由基(O2-·)和过氧化氢(H2O2)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和过氧化物酶(POD)、脯氨酸(Pro)、可溶性糖含量和地上生物量均呈明显上升趋势(P<0.05),叶绿素含量、电子传递速率(ETR)、相对外渗电导率、丙二醛(MDA)、类胡萝卜素(Car)和可溶性蛋白(Pr)含量均呈明显下降趋势(P<0.05);在盛花期,Pn、Fv/Fm、ETR、SOD、CAT、POD、Pro和地上生物量均呈明显上升趋势(P<0.05),其余指标均呈明显下降趋势(P<0.05);在成熟期,Pn、Fv/Fm、ETR、SOD、CAT、POD、Pro、可溶性糖和地上生物量均呈明显上升趋势(P<0.05),其余指标均呈明显下降趋势(P<0.05)。在初花期氯化镧处理后,在整个生育时期,除 Pro 外,叶绿素含量、Pn、Fv/Fm、ETR、SOD、CAT、POD、Car、可溶性糖、Pr和地上生物量均呈明显上升趋势(P<0.05),其余指标均呈明显下降趋势(P<0.05)。此外,60 mg·L-1的镧保护效果次之,90 mg·L-1最次,说明30 mg·L-1的氯化镧可以提高叶片酶活性,增强清除活性氧的能力,缓解低剂量UV-B辐射对叶片造成的氧化损伤。在UV-B辐射增强10%时,分枝期氯化镧处理后,在初花期,60 mg·L-1处理下紫花苜蓿Pn、Fv/Fm、SOD、CAT、POD、Pro、可溶性糖和地上生物量均呈明显上升趋势(P<0.05),其余指标呈明显下降趋势(P<0.05);在盛花期,Fv/Fm、SOD、CAT、POD、Car、Pro、可溶性糖和地上生物量均呈明显上升趋势(P<0.05),其余指标呈明显下降趋势(P<0.05);在成熟期,Fv/Fm、ETR、H2O2、SOD、CAT、POD、Car、Pro、可溶性糖和地上生物量均呈明显上升趋势(P<0.05),其余指标呈明显下降趋势(P<0.05)。初花期氯化镧处理后,在整个生育时期,除 ETR 和 Pro外,叶绿素含量、Pn、Fv/Fm、ETR、SOD、CAT、POD、Car、可溶性糖、Pr和地上生物量均呈明显上升趋势(P<0.05),其余指标呈明显下降趋势(P<0.05)。此外,30 mg·L-1的镧保护效果次之,90 mg·L-1最次,说明60 mg·L-1的氯化镧可以提高叶片酶活性,增强清除活性氧的能力,缓解高剂量UV-B辐射对叶片造成的氧化损伤。对比不同的喷施方案可知,在初花期喷施氯化镧溶液缓解UV-B辐射效果较明显于分枝期,缓解效果以盛花期和成熟期较为明显。更多还原

【Abstract】 The enhance UV-B radiation will inhibit photosynthetic characteristics of plant,damage cell membrane and the structure of biological membrane systems.The suitable concentration of lanthanum can improve the protective function of cell membrane,enhance the resistance of plants to adverse environment,Medicago sativa which known as "the king of grass",as a legume pasture,is widely cultivated in China and the world.In this paper,we had Medicago sativa as test materials to study the effects on physiological characteristics of Medicago sativa enhanced UV-B radiation(5%and 10%)on the growth period where Lanthanum chloride(LaCl3)(30.60 and 90 mg·L-1)was sprayed.in the branching stage and the early flowering stage,respectively.The results show:With UV-B radiation was enhanced by 5%,and the LaCl3 was sprayed in the branching stage.In the early flowering stage,the net photosynthetic rate(Pn).PSⅡmaximum photochemical quantum yield(Fv/Fm),superoxide anion free radical(O2-·),hydrogen peroxide(H2O2),superoxide dismutase(SOD),catalase(CAT)and peroxidase(POD),proline(Pro),soluble sugar content and aboveground biomass of Medicago sativa showed a significant increased treads(P<0.05),and chlorophyll content,electron transport rate(ETR),relative osmotic conductivity,malondialdehyde(MDA),carotenoid(Car)and soluble protein of Medicago sativa showed a significant increased treads(P<0.05)under sprayed LaCl3 with the concentrations of 30 mg·L-1.In the flowering stage,Pn,Fv/Fm,ETR,SOD,CAT,POD,Pro and aboveground biomass of Medicago sativa showed a significant increased treads(P<0.05).and the other indexes showed a significant decreased treads(P<0.05).In the mature stage.Pn,Fv/Fm,ETR,SOD,CAT,POD,Pro,soluble sugar and aboveground biomass of Medicago sativa showed a significant increased treads(P<0.05),and the other indexes showed a significant decreased treads(P<0.05).With the LaCl3 was sprayed in the flowering stage,chlorophyll content,Pn,Fv/Fm,ETR,SOD,CAT,POD.Car,soluble sugar,Pr and aboveground biomass of Medicago sativa showed a significant increased tread in the whole growth period(P<0.05).In addition,spraying LaCl3 with the concentrations of 60 mg-L"1 also had a protective effect but was inferior to that of 30 mg·L-1,and 90 mg·L-1 damage Medicago sativa leaves in conjunction with the effect of UV-B radiation.Therefore,sprayed LaCl3 with the concentrations of 30 mg·L-1 can improve the enzyme activity,enhance the ability to scavenge reactive oxygen species,and alleviate the oxidative damage and membrane lipid peroxidation caused by 5%of UV-B radiation.With UV-B radiation was enhanced by 10%,and the LaCl3 was sprayed in the branching stage.In the early flowering stage,Pn,Fv/Fm,SOD,CAT,POD,Pro,soluble sugar content and aboveground biomass of Medicago sativa showed a significant increased treads(P<0.05),the other indexes showed a significant decreased treads(P<0.05)under sprayed LaCl3 with the concentrations of 60 mg·L-1.In the flowering stage,Fv/Fm,SOD,CAT,POD,Car,Pro,soluble sugar and aboveground biomass of Medicago sativa showed a significant increased treads(P<0.05),and the other indexes showed a s,ignificant decreased treads(P<0.05).In the mature stage,Fv/Fm,ETR,H2O2,SOD,CAT,POD,Car,Pro,soluble sugar and aboveground biomass of Medicago sativa showed a significant increased treads(P<0.05),and the other indexes showed a significant decreased treads(P<0.05).With the LaCl3 was sprayed in the flowering stage,chlorophyll content,Pn,Fv/Fm,SOD,CAT,POD,Car,soluble sugar,Pr and aboveground biomass of Medicago sativa showed a significant increased tread in the whole growth period(P<0.05).In addition,spraying LaCl3 with the concentrations of 30 mg·L-1 also had a protective effect but was inferior to that of 60 mg·L-1,and 90 mg·L-1 damage Medicago sativa leaves in conjunction with the effect of UV-B radiation.Therefore,sprayed LaCl3 with the concentrations of 60 mg·L-1 can improve the enzyme activity,enhance the ability to scavenge reactive oxygen species,and alleviate the oxidative damage and membrane lipid peroxidation caused by 10%of UV-B radiation.The T test showed that during the early flowering stage of sprayed LaCl3 has obvious effect to reduce UV-B radiation,and the relief stage was in first stage.更多还原