Li Chen-Yang, Li Lin, Qi Li-Pan, Guo Xiao-Min, Gong Xue-Chen, Liu Yi-Qiang, Zhao Yue, Song Ya-Hui
Hebei North University, Zhangjiakou, 075000, Hebei, China.
Ying Yong Sheng Tai Xue Bao. 2020 Dec;31(12):4147-4152. doi: 10.13287/j.1001-9332.202012.029.
We examined the effects of shading photosynthetic characteristics, yield, and tolerance to low light in two potato varieties (Jizhangshu 12 and Jizhangshu 8) at four growth stages (seedling, seedling/budding, budding/early flowering and flowering/harvest). There were three shading treatments (0(CK), 20% and 50%). The results showed that at both 20% and 50% shading rates, the SPAD value (a measure of leaf cellular chlorophyll content) of the two varieties decreased significantly at the seedling stage compared with CK treatment. No significant change in the SPAD value occurred at the seedling/budding stage or the budding/early-flowering stage. However, the SPAD value increased marginally after shading at the initial flowering stage. Under the 50% shading regime, the SPAD values of both varieties followed the same trend as the 20% regime. The range of changes at different growth stages remained similar. The only exception was that shading at the beginning of flowering increased SPAD value. Shading had little effect on leaf stomatal conductance () at each developmental stage. There was no significant difference between all treatments and the control, except that the value of Jizhangshu 8 decreased significantly (43.9%) compared with the control under 50% shading at the beginning of flowering. After the shading treatment, the intercellular CO concentration () of leaves showed an upward trend. 50% shading at the seedling and seedling/budding stages could significantly increase , but not at other stages. The net photosynthetic rate () of the four periods were all decreased after 15 d of shading. The reduction of the two varieties, 50% shading, was greater than 20% shading. The decline range of of Jizhangshu 12 was less than that of Jizhangshu 8 at all stages, except for that at the seedling stage. The yield of shading treatments decreased in all four stages, with the decrease rate of 50% shading treatment being greater than that of the 20% shading treatment. 'Jizhangshu 12'was not tolerant to low light at the seedling stage but performed better than 'Jizhangshu 8' at other stages. The comprehensive analysis of two test varieties implied that varieties with strong tolerance to low light experienced a smaller boost in intercellular CO concentration and a smaller drop in net photosynthetic rate, stomatal conductance, and yield post-shading.
我们研究了在四个生长阶段（幼苗期、幼苗/现蕾期、现蕾/初花期和开花/收获期）对两个马铃薯品种（冀张薯12和冀张薯8）进行遮荫处理后，其光合特性、产量及耐弱光性的影响。设置了三种遮荫处理（0（对照）、20%和50%）。结果表明，在20%和50%的遮荫率下，与对照处理相比，两个品种在幼苗期的SPAD值（衡量叶片细胞叶绿素含量的指标）显著降低。在幼苗/现蕾期或现蕾/初花期，SPAD值没有显著变化。然而，在初花期遮荫后，SPAD值略有增加。在50%遮荫处理下，两个品种的SPAD值变化趋势与20%遮荫处理相同。不同生长阶段的变化幅度相似。唯一的例外是在开花初期遮荫会增加SPAD值。遮荫对各发育阶段叶片气孔导度（）影响较小。除了在开花初期50%遮荫处理下冀张薯8的气孔导度值与对照相比显著降低（43.9%）外，所有处理与对照之间没有显著差异。遮荫处理后，叶片细胞间CO浓度（）呈上升趋势。在幼苗期和幼苗/现蕾期进行50%遮荫可显著提高细胞间CO浓度，但在其他阶段则不然。遮荫15天后，四个时期的净光合速率（）均下降。两个品种在50%遮荫处理下的净光合速率下降幅度大于20%遮荫处理。除了在幼苗期，冀张薯12在所有阶段的净光合速率下降幅度均小于冀张薯8。四个阶段的遮荫处理产量均下降，50%遮荫处理的下降速率大于20%遮荫处理。“冀张薯12”在幼苗期不耐弱光，但在其他阶段表现优于“冀张薯8”。对两个试验品种的综合分析表明，耐弱光性强的品种在遮荫后细胞间CO浓度的增加幅度较小，净光合速率、气孔导度和产量的下降幅度也较小。
