低温胁迫对不结球白菜光合及叶绿素荧光特性的影响

Effects of Low Temperature on Photosynthetic and Fluorescent Parameters of Non-heading Chinese Cabbage

以盆栽的耐寒性不同的不结球白菜品系001、007和010为材料,在玻璃温室中对各品系进行常温(CK,昼/夜温度为20℃/15℃)和低温(昼/夜温度为7℃/2℃)处理,研究低温对不结球白菜的冷害指数、光合指标和叶绿素荧光参数的影响.结果表明:低温胁迫条件下,3个品系不结球白菜的净光合速率(Pn)均较CK显著下降,PSⅡ最大光化学效率(Fv/Fm)、电子传递速率(ETR)和光化学猝灭系数(qP)显著降低,而品系001各项指标显著高于其他品系;不同品系非光化学猝灭(NPQ)均呈增加趋势,品系间增加幅度差异不显著.低温胁迫下,品系001叶片吸收的光能中用于有效电子传递的比例较高,光合受抑程度较轻;007和010的电子传递速率显著下降,过剩激发能显著高于001,光合活性受损较严重.研究发现,低温胁迫下各不结球白菜品系非光化学耗散差异不显著,电子传递的有效性和光化学效率的差异是导致各品系耐冷性差异的主要原因.

The effects of low temperature on cold tolerance,net photosynthetic and chlorophyll fluorescent parameters of non-heading Chinese cabbage（Brassica campestris L.ssp.chinensis Makino） were studied.Three lines were used in the experiment：＇001＇,＇007＇ and ＇010＇.The plants were grown in pots and environment was controlled in greenhouse.Two temperature treatments were set for each line：（1）Day temperature at（20±2）℃ and night temperature at（15±2）℃（control）,（2）Day temperature at（7±2）℃ and night temperature at（2±2）℃（low temperature）.The results showed that the chilling injury index of line ＇001＇ was less than those of line ＇007＇ and ＇010＇.The leaves net photosynthetic rate（Pn）,PSⅡ primary photochemical efficiency（Fv/Fm） and electron transfer rate（ETR） decreased significantly than those of the control for all three lines after treated under low temperature for 9 days.These parameters of line ＇001＇ plants decreased less and showed less photo inhibition than that of line ＇007＇ and ＇010＇.Non-photochemical quenching coefficient（NPQ） of all lines increased significantly.All data suggested that more photo energy assimilated was used in photosynthesis,and was transformed into chemical energy in ＇001＇ than that in ＇007＇ and ＇010＇.The excessive product of excited energy were fewer,and injury to photosynthetic apparatus was less in ＇001＇,so that wider adaptability had been shown in plants of ＇001＇ under low temperature than that of ＇007＇ and ＇010＇.