富营养化水体水淹和水淹后干旱对降香黄檀生理生态的影响

Effects of Simulated Eutrophic Waterlogging and Post-waterlogging Drought on the Eco-physiological Characteristics of Dalbergia odorifera

摘要:

为探究富营养化水体水淹及水淹后干旱对陆生木本植物耐淹和耐旱性的影响，以1 a生降香黄檀(Dalbergia odorifera)为对象，第1阶段设置对照(CK)、养分(H)、水淹(W)和富营养化水淹(WH)处理，第2阶段设置对照-干旱(CKD)、养分-干旱(HD)、水淹-干旱(WD)和富营养化水淹-干旱(WHD)处理，研究不同水分和养分处理对降香黄檀幼苗生长和生理的影响。结果表明, 降香黄檀幼苗在所有处理下均有较高的存活率；W和WH处理降低了幼苗的茎高增量、总生物量、净光合速率、气孔导度、总叶绿素含量和叶片水势，但增加了幼苗的超氧化物歧化酶(SOD)和过氧化物酶(POD)活性、可溶性蛋白和H₂O₂含量, 且这种变化在W组中更明显。与第1阶段相比，CKD和HD组幼苗的生物量增长量显著降低，而WD和WHD组呈现相反趋势。其次，与CKD和HD处理相比，WD和WHD处理增加了幼苗的净光合速率，降低了幼苗的SOD活性和H₂O₂含量，且WHD组幼苗具有比WD组更高的生物量增长量、总叶绿素含量、POD活性以及更低的类胡萝卜素含量。这表明养分供给在一定程度上能缓解水淹对幼苗生长的消极影响，前期水淹尤其是富营养化水淹有利于幼苗在后期干旱条件下的生物量积累。

Abstract:

In order to explore the effects of eutrophic waterlogging and post-waterlogging drought on the tolerance of terrestrial woody plants, the control (CK), nutrient (H), waterlogging (W) and eutrophication waterlogging (WH) treatments were set in the first stage. In the second stage, control-drought (CKD), nutrient- drought (HD), watering-drought (WD) and eutrophic watering-drought (WHD) treatments were set up to study the effects of different water and nutrient treatments on the growth and physiology of one-year-old Dalbergia odorifera seedlings. The results showed that D. odorifera had high survival under all treatments; the seedlings exhibited the highest biomass, net photosynthetic rate and total chlorophyll concentration under H treatment. In contrast, both W and WH treatments significantly reduced stem height increment, total biomass, net photo- synthetic rate, stomatal conductance, total chlorophyll content and leaf water potential, but significantly increased the activities of superoxide dismutase (SOD), peroxidase (POD), and contents of H₂O₂ and soluble protein. Notably, the impact of W stress was more pronounced than that of WH stress. Compared with the first stage, the biomass increment decreased significantly under both of CKD and HD treatments, but which showed the opposite trend under WD and WHD. Furthermore, compared with CKD and HD treatments, net photosynthetic rate significantly increased, while SOD activity and H₂O₂ content decreased under WD and WHD. Moreover, compared with WD, biomass increment, total chlorophyll content and POD activity increased under WHD, but Car content decreased. Therefore, it was demonstrated that nutrient supply could alleviate the negative effects of waterlogging on seedling growth of D. odorifera to a certain extent, and early waterlogging, especially eutro- phication waterlogging, was conducive to biomass accumulation of seedlings under later drought condition.