不同盐碱水平对黄瓜幼苗生长及生理特性的影响OA

[Objectives]The paper aimed to explore the effects of different levels of saline-alkali treatment on the growth and physiology characteristics of cucumber seedlings,in order to lay the foundation for saline-alkali tolerant cultivation of cucumber.[Methods]The saline-alkali mixtures of 25(T1),50(T2),75(T3),100(T4),125(T5),150(T6),175(T7)and 200(T8)mmol•L-1 separately were prepared using NaCl,Na2 SO4,NaHCO3 and Na2 CO3 according to 1∶9∶1∶9 concentration ratio,and the clear water(CK)was as the control.The seedlings of cucumber were quantitatively treated.The indexes of seedling growth were measured at 5,10 and 15 d after treatment,and physiological indexes including of chlorophyll content,photosynthetic parameters,root activity and antioxidant were measured at 7 d after treatment.Principal component analysis(PCA)was used to analyze the indexes of cucumber seedlings under saline-alkali stress.[Results]The plant height,stem diameter,leaf area and leaf number of cucumber seedlings were significantly inhibited at 5 and 10 d after saline-alkali treatment,and the indexes decreased significantly at 15 d compared with those of the control,and the plant height,stem diameter,leaf area and leaf number of T8 treatment decreased the most significantly,which were significantly reduced by 85.68%,56.54%,66.94%and 53.52%,respectively,compared with the control.The leaf dry weight,leaf fresh weight,root length,root tip number,transpiration rate,net photosynthetic rate and leaf K+content significantly decreased compared with those of the control under the lower concentration saline-alkali treatments such as T1-T3,which were 15.35%-32.53%,7.04%-16.90%,14.25%-32.50%,17.88%-26.85%,6.68%-46.30%,15.76%-36.15%and 7.80%-19.79%,respectively.However,the contents of chlorophyll a,chlorophyll b,carotenoids and leaf Mg2+increased under the higher concentration saline-alkali treatments such as T4-T8,which increased by 13.84%-25.42%,1.63%-39.74%,1.41%-15.47%and 3.75%-8.83%of the control.The principal component analysis showed that plant height,stem diameter,dry weight,fresh weight,root tip number,transpiration rate,net photosynthetic rate and leaf K+content could be used as evaluation indicators for plant growth under T1-T3 low concentration salinity-alkali treatments.Total chlorophyll,carotenoids,leaf Mg2+content and other indexes could be used as evaluation indicators for high saline-alkali concentration treatments such as T4-T8.[Conclusions]The indexes which were plant height,stem diameter,dry weight,fresh weight,root tip number,transpiration rate,net photosynthetic rate and leaf K+content could be used as the evaluation ones at the lower saline-alkali concentration treatments,and the total chlorophyll,carotenoids and leaf Mg2+content could be used as the evaluation ones at the higher saline-alkali concentration treatment.