硝酸镧对甜瓜叶片生理指标和果实品质的影响

以甜瓜为材料,研究了叶面喷施硝酸镧对甜瓜生长发育的影响,并探讨叶片抗病性相关酶活性与植株生长和果实品质之间的相关性。采用5个浓度的La(NO3)3溶液(0,100,150,200,250,300 mg/L),于伸蔓期、始花期、膨瓜期各喷施甜瓜叶面1次,测定3个生长时期甜瓜叶片中超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)和多酚氧化酶(PPO)活性,以及叶绿素,类胡萝卜素和丙二醛(MDA)含量,测定各处理的单瓜重、可溶性固形物、可溶性糖和Vc含量。结果表明:(1)在各处理中,200 mg/L硝酸镧处理效果最显著,其中甜瓜叶片的叶绿素含量为各处理中最高,SOD,PPO和CAT活性最高,POD活性和MDA含量最低,果实品质最佳,可溶性糖和维生素C含量均呈最高值;(2)250 mg/L以上浓度的硝酸镧处理则抑制甜瓜生长,降低其产量和品质。因此,适宜浓度的硝酸镧(200 mg/L)处理具有促进甜瓜生长、增强植株抗逆性的效应。

Effects of La(NO_3)_3 on the Fruit Quality and Physiological Indicators of Muskmelon Leaves

The effects of La（NO ₃）₃ on the growth and development of muskmelon by spraying on the foliage were studiedAnd we probed the interrelationships between the activity of resistance related enzyme and the plant growth and fruit qualityOn the foliage of muskmelon at straw period，incipient blooming period and fruit expansion period were sprayed with 0，100，150，200，250 and 300mg/L La（NO ₃）₃ solution，the activities of superoxide dismutase（SOD），peroxidase（POD），catalase（CAT），polyphenol oxidase（PPO）and the contents of chlorophyll，carotenoids，malondialdehyde（MDA）in muskmelon leaves at three growing periods were determinedAnd we tested the single fruit weight and the contents of the total soluble solids，the soluble sugar and Vitamin CThe result was as below（1）Treating with 200mg/L La （NO ₃）₃ solution had the most significant effectThe activities of SOD，POD，CAT，PPO and the contents of chlorophyll and MDA in muskmelon leaves at three growing periods were all highestAnd the fruit quality was best with the highest content of the soluble sugar and Vitamin C;（2）While the plants were treated with more than 250 mg/L La （NO ₃）₃，their growth was resisted and the yield and quality went downTherefore，we concluded that treating with appropriate concentration of La （NO ₃）₃(200mg/L）could effectively promote the plant growth and enhance the plant resistance in muskmelon.