摘要：

为探究外源24-表油菜素内酯(EBR)对盐胁迫下枸杞幼苗生理特性的影响,以宁夏枸杞宁杞7号为试验材料,设置0 mmol/L NaCl+蒸馏水喷叶(CK)、150 mmol/L NaCl+蒸馏水喷叶(N0)、150 mmol/L NaCl+0.005 mg/L EBR(T1)、150 mmol/L NaCl+0.050 mg/L EBR(T2)、150 mmol/L NaCl+0.500 mg/L EBR(T3)5个处理,分别在盐胁迫第7,14,21天测定幼苗株高、基径、地上生物量、地下生物量、叶绿素含量、光合参数、抗氧化酶活性和渗透调节物质含量。结果表明,与N0处理相比,T1、T2、T3处理枸杞幼苗株高、基径、地上生物量和地下生物量,叶片光合色素,净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr),超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性和渗透调节物质含量均显著升高,胞间CO₂浓度(Ci)和丙二醛(MDA)含量均显著降低,其中,T2处理效果最佳。盐胁迫第21天,与N0处理相比,T2处理枸杞幼苗株高、基径、地上生物量和地下生物量分别增加23.63%,15.45%,17.70%和47.06%;Chla、Chlb和Chla+b含量分别增加10.68%,12.31%和6.57%;Pn、Tr、Gs分别增加55.53%,27.83%和9.76%,Ci降低14.42%;SOD、POD和CAT活性分别提高13.23%,20.10%和9.31%;MDA含量降低35.28%;脯氨酸含量、可溶性糖含量和可溶性蛋白含量分别增加45.17%,86.54%和57.00%。综上所述,外源适宜浓度EBR可以促进盐胁迫下枸杞幼苗生长,提高枸杞幼苗光合能力、抗氧化酶活性,增加渗透调节物质含量,缓解盐胁迫对枸杞幼苗的伤害,提高枸杞的耐盐性,其中,外源0.050 mg/L EBR效果最佳。

关键词: 枸杞, 盐胁迫, 24-表油菜素内酯, 光合参数, 抗氧化酶, 渗透调节

Abstract:

In order to investigate the effect of exogenous 24-epibrassinolide(EBR)on the physiological characteristics of Lycium barbarum seedlings under salt stress,Ningxia L. barbarum Ningqi 7 was used as the experimental material.Five treatments were set up,namely 0 mmol/L NaCl+distilled water spray(CK),150 mmol/L NaCl+distilled water spray(N0 treatment),150 mmol/L NaCl+0.005 mg/L EBR(T1 treatment),150 mmol/L NaCl+0.050 mg/L EBR(T2 treatment),and 150 mmol/L NaCl+0.500 mg/L EBR(T3 treatment).The seedling plant height,basal diameter,aboveground and underground biomass,chlorophyll content,photosynthetic parameters,antioxidant enzyme activity and the content of osmoregulatory were measured on the 7th day,14th day,and 21st day respectively.The results showed that compared with N0 treatment,T1,T2,T3 treatments significantly increased the plant height,basal diameter,aboveground and underground biomass,photosynthetic pigments in leaves,net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr), superoxide dismutase (SOD), peroxidase (POD), catalase(CAT)activities,as well as the content of osmoregulatory in L.barbarum seedlings,intercellular CO₂ concentration (Ci) and malondialdehyde (MDA) content significantly decreased,T2 treatment had the best effect.On the 21st day of salt stress,compared to the N0 treatment,the plant height,basal diameter,aboveground and underground biomass of L.barbarum seedlings increased by 23.63%,15.45%,17.70%,and 47.06%,the content of Chlorophyll a,Chlorophyll b,and Chlorophyll a+b increased by 10.68%,12.31%,and 6.57%,respectively;Pn,Tr,and Gs increased by 55.53%,27.83%,and 9.76%,respectively;the Ci value decreased by 14.42%;the activities of SOD,POD,and CAT increased by 13.23%,20.10%,and 9.31%,respectively;the MDA content decreased by 35.28%;the proline content,soluble sugar content,and soluble protein content increased by 45.17%,86.54%,and 57.00%,respectively.In summary,an appropriate concentration of exogenous 24-epibrassinolide can promote the growth of L.barbarum seedlings under salt stress,improve the photosynthetic capacity and antioxidant enzyme activity of L.barbarum seedlings,increase the content of osmoregulatory substances,alleviate the damage of salt stress to L.barbarum seedlings,and enhance the salt tolerance of L.barbarum seedlings.Among them,exogenous 0.050 mg/L EBR has the best effect.

Key words: Lycium barbarum, Salt stress, 24-epibrassinolide, Photosynthetic parameters, Antioxidant enzymes, Osmoregulation