叶片喷施甲醇和乙醇对油菜生长及光合特性的影响

Comparison of the effects of foliar application of methanol and ethanol on the growth and photosynthetic characteristics in Brassica napus L.

用5%甲醇、乙醇分别喷施4个品种油菜叶片,以喷施自来水的植株为对照,研究喷施甲醇和乙醇对油菜植株生长及光合特性的影响。结果表明:叶片喷施甲醇、乙醇使油菜植株生物量分别增加90%、329%;根冠比分别增加57%、70%;气孔导度分别增加20%、33%;蒸腾速率分别增加24%、87%;胞间CO2浓度分别增加9%、20%;净光合速率分别增加18%、52%;叶片中叶绿素a含量分别增加17%、63%,叶绿素b含量分别增加42%、64%,总叶绿素含量分别增加26%、59%;叶片过氧化氢含量分别降低69%、71%。说明施用甲醇和乙醇可显著降低叶片内过氧化氢含量,增加叶片叶绿素含量和气孔传导率,增加叶片细胞内CO2浓度,有效提高光合作用的效率,从而促进油菜植株的生长,其中乙醇促进油菜生长和光合作用效果较甲醇明显。

This study investigated the effects of foliar spraying 5 % methanol and ethanol on the growth and photosynthetic characteristics of the pot-grown Brassica napus L. Methanol and ethanol spraying was conducted for four weeks and twice a week. The Brassica napus L. sprayed with distilled water was used as the control. The results showed that foliar application of methanol and ethanol led to an increase in plant biomass by 90% and 329M, in the ratio of root to shoot biomass by 57% and 70%, in stomatal conductance by 20% and 33%/, in transpiration rate by 24% and 87%, in intercellular CO2 concentration by 9% and 20%, in photosynthetic rate by 18% and 52%, in chlorophyll a content by 17% and 63%, in chlorophyll b content by 42% and 64%, and in total chlorophyll content by 26% and 59%, respectively; but led to a decrease in leaf H2O2 content by 69 % and 71%, respectively. These results indicated that application of methanol and ethanol significantly reduced the leaf H2O2 content, increased leaf chlorophyll content, stomatal conductance and leaf intercellular CO2 concentration, improved the photosynthesis, thus promoted the plant growth. Moreover, the effects of ethanol spraying on the plant growth and photosynthesis were significantly better than those of methanol.