钾素水平对网纹甜瓜叶片光合特性及叶绿体亚显微结构的影响

Effects of potassium level on photosynthetic characteristics and chloroplast submicroscopic structure of muskmelon leaves.

在设施基质栽培条件下,研究了营养液中120、240及360 mg.L-13个钾素水平对网纹甜瓜‘甜甜1号’叶片光合特性及叶绿体亚显微结构的影响.结果表明,营养液中钾素水平过低(120 mg.L-1)或过高(360 mg.L-1)均导致网纹甜瓜叶片净光合速率下降,使叶绿体片层结构混乱、变形和片层数减少,但对CO2补偿点(70μl.L-1)、饱和CO2(600μl.L-1)、光补偿点(50μmol.m-2.s-1)无显著影响.适宜的钾素水平能显著提高叶片的饱和光强、羧化效率和表观量子效率,3个指标分别为1 200μmol.m-2.s-1、0.1364和0.0237.在试验条件下,提高温室内基质栽培网纹甜瓜叶片光合效率的最适钾素水平为240 mg.L-1.

With soiUess culture in greenhouse, this paper studied the effects of three potassium （K） levels （120, 240, and 360 mg · L^-1） on the photosynthetic characteristics and chloroplast submicroscopic structure of muskmelon cv. ‘ Tiantian No. 1 ＇ leaves. The resuhs showed that at low （120 mg · L^-1） and high （360 mg · L^-1） K levels, the net photosynthetic rate （P,） decreased, chloroplast lamellar structure disordered, and lamella number decreased. No significant effects were observed on CO2 compensation point （70 μl · L^-l ） , saturation CO2 for photosynthesis （600μl · L^-1 ） and light compensation point （50μmol· m^-2 ·s^-1 ） at the three K levels. The saturation light for photosynthesis, carboxylation efficiency and apparent quantum yield at 240 mg · L^ -1 K level were significantly higher, being 1 200 μmol·m^-2 · s^-1, 0. 1364 and 0. 0237, respectively. Under the conditions of this study, the optimal K level in the nutrient solution for muskmelon soilless culture was 240 mg · L^-1.