不同光温背景下镧对辣根生态生理学效应(Ⅰ):对辣根光合作用影响

Eco-physiological Effects of La on Cochlearia armoracia L.at Different Temperatures and Light Intensities(Ⅰ):Effects on Photosynthesis of Cochlearia armoracia L.

采用土培法培养试验,研究在不同光照(1.5、3.0、5.0、8.0、12.0、20.0klx)和温度(10、15、20、25、30、40℃)条件下稀土镧(La)对辣根光合作用的影响。结果表明,辣根适宜生长温度为15～25℃,适宜浓度稀土La(Ⅲ)能明显提高辣根的叶绿素(Chl)含量、净光合速率(Pn)、气孔导度(Gs)、胞间CO2浓度(Ci),其中以20mg·L-1效果最佳;高、低温下喷施La(Ⅲ)不利于辣根的光合。在较低光照幅度下,La(Ⅲ)仍能有效促进辣根光合作用,呈“低促高抑”现象。且在较低的光照幅度范围内,对较低光照幅度下的促进作用优于较高光照幅度。

Cochlearia armoracia L. is an important industrial crop, and the rare earth could enhance the quality and yield of Cochlearia armoracia L.. Effects of lanthanum （La） on photosynthesis of Cochlearia armoracia L at different temperatures （10, 15, 20, 25, 30, 40 ℃） and light intensities （1.5, 3.0, 5.0, 8.0, 12.0, 20.0 klx） were studied in a pot experiment. The results showed that the optimum temperature range for Cochlearia armoracia L. growth was 15-25℃. Chlorophyll （Chl） content, photosynthetic rate （Pn）, stomatal conductance （Gs）, intercellular CO2 concentration （Ci） were significantly increased by low concentration of La（Ⅲ） （5-25 mg·L^-1） in the optimum temperature range, but reduced with the concentration increasing of La（Ⅲ）. The optimum dosage of La（Ⅲ） was 20 mg·L^-1. Chl content, Pn, Gs and Ci in La（Ⅲ） pretreatment were all lower than those of the control （CK）, indicating that La（Ⅲ） application was infeasible in high and low temperature. The effect of RE on improving plant resistance to temperature stress differed with plant type and treatment method. In low light intensity, La（Ⅲ） could improve Cochlearia armoracia L. photosynthesis, and presented ＂Hormesis＂ phenomenon. And in low light range, the improvement of RE in comparative low light intensity was better than relative high light intensity.