五种园林灌木对NaCl胁迫的光合特性响应比较研究

Comparative study on photosynthetic characteristics responses of 5 garden shrubs under Na Cl stress

以夹竹桃(Thevetia peruviana)、海桐(Pittosporum tobira)、花叶假连翘(Duranta repens)、朱槿(Hibiscus rosa-sinensis)、蔓马缨丹(Lantana montevidensis)5种华南滨海地区常用园林灌木为材料,于种植土中添加不同梯度Na Cl(含盐量为100、300mmol/kg)人工盐处理模拟华南滨海地区土壤,研究植株胁迫20d和40d的光合气体交换效率及荧光动力变化情况。随着盐胁迫时间的延长,5种灌木的净光合速率(Pn)、气孔导度(Gs)和胞间CO2浓度(Ci)均逐渐降低,且随着胁迫浓度增加趋势进一步加强。5种灌木的非光化学淬灭系数(NPQ)和非调节性能量耗散量子产额Y(NO)均逐步增加,且随着胁迫浓度增加趋势进一步加强。在100mmol/kg浓度盐胁迫下,花叶假连翘的蒸腾速率(Tr)随着时间的延长先减少后增加,海桐和蔓马缨丹逐渐减少;在300mmol/kg浓度盐胁迫下,花叶假连翘的Y(NO)先减少后增加,其他灌木逐渐减少。在100mmol/kg浓度盐胁迫下蔓马缨丹的有效光化学量子产量Y(Ⅱ)先减少后增加,其他灌木逐渐减少;在300mmol/kg浓度盐胁迫下5种灌木的Y(Ⅱ)逐渐减少。隶属函数综合评价结果表明,5种灌木耐盐性表现为夹竹桃>海桐>朱槿>蔓马缨丹>花叶假连翘。

Five garden shrubs commonly used in Southern China coastal areas were selected as research materials,including Thevetia peruviana,Pittosporum tobira,Duranta repens,Hibiscus rosa-sinensis and Lantana montevidensis.Different gradients of salt content from 100 mmol/kg and 300 mmol/kg were applied in the planted soil,to analyze the changes in photosynthesis and chlorophyll fluorescence dynamics index in different stress duriation for 20 d and 40 d.With the prolongation of salt stress time,the Pn,Gs and Ci of the 5 shrubs decreased gradually,and further strengthened with the increase of stress concentration.The NPQ and Y(NO)of 5 shrubs increased gradually,and were further strengthened with the increasing trend of stress concentration.Under the stress of 100 mmol/kg concentration,the Tr decreased with the increase of time gradually.Under the stress of 300 mmol/kg,the Y(NO)of Duranta repens increased first,and the other shrubs decreased gradually.The Y(Ⅱ)of Lantana montevidensis decreased and the other shrubs decreased gradually,and the Y(Ⅱ)of 5 shrubs decreased gradually under the concentration of 300 mmol/kg.The results showed that the salt tolerance of these 5 shrubs was:Thevetia peruviana>Pittosporum tobira>Hibiscus rosa-sinensis>Lantana montevidensis>Duranta repens.