磷素对甜瓜幼苗根系生理活性物质的影响

The Effect of Phosphorus Element on the Root Physiological Active Substance of Muskmelon Seedling

为研究磷素对甜瓜幼苗根系形成的生理机制,本试验在现代化温室条件下,以金妃甜瓜为材料,采用基质培养方法,设置了5个磷素处理水平（分别为0.3、0.6、0.9、1.2、1.5 mmol·L^-1）,测定甜瓜根系鲜重、干重、根体积、根系活力、蛋白质、硝态氮含量以及硝酸还原酶、过氧化氢酶、过氧化物酶、抗坏血酸氧化酶、多酚氧化酶活性的变化规律。结果表明：适宜磷素用量（即0.9-1.2 mmol·L^-1）时,对幼苗根系生长促进作用最强,可以显著增加根系鲜重、根系干重和根体积,提高根系活力、硝态氮和蛋白质含量,增强硝酸还原酶、过氧化氢酶、过氧化物酶和抗坏血酸氧化酶活性。而当磷素用量低于0.6 mmol·L^-1或高于1.5 mmol·L^-1时,各项指标均显著下降。通过研究磷素营养对甜瓜幼苗生长过程中根系形态变化、物质积累和生理特性的影响,明确磷素对甜瓜幼苗根系形成的作用效应,为甜瓜生产合理施用磷肥提供理论依据,为甜瓜壮苗培育、高产生产提供技术依据。

To study the physiological mechanism of phosphorus element on the root formation of muskmelon,muskmelon（ Jin- fei） was used as experimental material under modern greenhouse,by measuring the muskmelon root matter accumulation,morphological indexes and physiological indexes,to investigate the effect of phosphorus element on root physiological active substance of muskmelon seedling. Through substrate culture method,under different phosphorus levels of 0. 3,0. 6,0. 9,1. 2,1. 5 mmol ·L^-1,respectively,root fresh weight,root dry weight,root volume,root activity,soluble protein content,nitrate nitrogen content,nitrate reductase activity,catalase activity,peroxidase activity,ascorbic acid oxidase activity and polyphenol oxidase activity were measured to reveal the mechanism of different phosphorus levels on muskmelon and provide the theoretical basis on phosphorus efficiency cultivating. The results showed that appropriate dosage of phosphorus element（ 0. 9 - 1. 2 mmol·L^-1） can best promote root growth of seedling through increasing the root fresh weight,root dry weight and root volume,improving root activity,soluble protein content and nitrate nitrogen content,promoting nitrate reductase activity,catalase activity,peroxidase activity and ascorbic acid oxidase activity. While phosphorus dosage was less than 0. 6 mmol·L^-1or higher than 1. 5 mmol·L^-1,all indexes decreased significantly. The action effects of phosphorus on muskmelon seedling root formation was defined by researching on the effects of phosphorus on root morphological changes, matter accumulation and physiological characteristics during seedling growth of muskmelon,therefore,this study provided the theory basis for application rationally phosphorus fertilizer in muskmelon production,and technical guarantee for muskmelon strong seedling and high yield production.