冷冻胁迫下磷肥对紫花苜蓿根颈含水量及氨基酸代谢的影响

在科尔沁沙地,以公农1号紫花苜蓿为供试品种,采用大田试验,对紫花苜蓿施用重过磷酸钙和磷酸二铵,磷肥(P2O5)施用量分别为0、100、200、300和400kg/hm2,越冬前期挖取紫花苜蓿根颈,人工模拟冷冻(20℃)和冷藏(4℃)处理,分析紫花苜蓿根颈的相对电导率、含水量(自由水和束缚水)和氨基酸(游离氨基酸和脯氨酸...

Effects of Phosphate Fertilizer on Root Crown Water Content and Amino Acid Metabolism of Alfalfa under Freezing Stress

In Horqin Sandy Land,taking Gongnong No.1 as the test alfalfa variety,a field experiment was conducted to explore the effects of calcium triple superphosphate(TSP)and diammonium phosphate(DAP)on alfalfa.The application rates of P₂O₅ were 0,100,200,300,400 kg/hm²,respectively.In the early stage of overwintering,alfalfa root crowns were collected and treated under artificially simulated freezing(-20℃)and cold storage(4℃)conditions to analyze the changes of relative conductivity,water(free water and bound water)content and amino acid(free amino acid and proline)content.The results showed that compared with cold storage condition,low temperature freezing treatment had lower free water content and higher relative conductivity,and contents of proline and bound water.Lower relative electrical conductivity and higher contents of proline and bound water of alfalfa root crown were observed under low temperature freezing treatment with addition of 300 kg/hm² phosphate fertilizer.Furthermore,under above condition,the relative conductivity with TSP addition was lower than that of DAP addition,and the contents of proline and bound water in TSP addition was higher than those of DAP addition.The correlation analysis revealed that under low temperature freezing treatment,the relative conductivity of alfalfa root crown with TSP addition was positively correlated with the free water content(P<0.05)and negatively correlated with the bound water content(P<0.01).In conclusion,the application of 300 kg/hm²(P₂O₅)in Horqin Sandy Land in autumn was beneficial to the safe overwintering of alfalfa,and TSP addition had better effect than DAP addition.