耐亚磷酸盐紫花苜蓿品种筛选及评价指标的鉴定

亚磷酸盐是正磷酸盐的一种还原形态,具有溶解度高、运输效率高、与土壤反应活性低等优势.通过探讨不同紫花苜蓿品种苗期对亚磷酸盐的耐逆能力,旨在为紫花苜蓿耐亚磷酸盐品种筛选和亚磷酸盐新型磷肥的开发提供科学依据.以37个紫花苜蓿品种为试验材料,设置正磷酸盐(0.5 mmol·L-1 KH2PO4)和亚磷酸盐(0.5 mmol·...

Screening of phosphite-tolerant alfalfa varieties and identification of phosphite tolerance indicators

Phosphite， a reduced form of orthophosphate， is characterized by its high solubility， high transport efficiency， and low reactivity in soil. The aim of this study was to screen for phosphite-tolerant alfalfa varieties and provide information for the development of phosphite fertilizers by exploring differences in phosphite tolerance among different varieties of alfalfa at the seedling stage. Thirty-seven alfalfa varieties were cultured in Hoagland’s nutrient solution with orthophosphate （0.5 mmol·L^-1 KH₂PO₄） or phosphate （0.5 mmol·L^-1 KH₂PO₃） as the sole phosphorus resource. We analyzed 12 morphological and physiological characters： Plant height （PH）， stem diameter（SD）， shoot phosphorus content （SPC）， shoot dry weight （DWS）， root dry weight （DWR）， root∶shoot， total root length （RL）， root surface area （RSA）， root phosphorus content （RPC）， chlorophyll content （Chl）， leaf area （LA）， and net photosynthetic rate （P_n）. Based on the phosphite-tolerance coefficient （PTC） of each individual index， we used principal component analysis， membership function analysis， cluster analysis， and stepwise regression to comprehensively evaluate phosphite tolerance characteristics and establish a mathematical model. The results showed that phosphite stress resulted in increased root total phosphorus content， increased chlorophyll content， and decreased values of other indexes in different varieties. The 12 indicators were divided into five composite indicator groups in a principal component analysis. The 37 alfalfa varieties were classified into four categories in terms of phosphite resistance： highly resistant （two varieties； WL903 and Kehan）； Moderately resistant （12 varieties）； Low resistance （17 varieties）， and sensitive （six varieties）. The following regression model was developed for evaluating phosphite tolerance： Y=-0.174+0.102PH+0.189DWR+0.168RL+0.187RSA-0.061P_n （R²=0.9908）. The precision of the regression equation was higher than 93.22% for each alfalfa variety. The results show that the highly phosphite-resistant alfalfa varieties were Kehan and WL903. Under phosphite stress， the tolerance of alfalfa varieties to phosphite can be quickly identified and predicted by measuring PH， DWR， RL， RSA， and P_n.