摘要
为了阐明干热河谷甜玉米灌浆期叶片光合生理特征对光照和土壤水分的适应机制,明确其土壤水分阈值效应,本文采用大田人工给水结合自然耗水获得土壤水分梯度的方法,利用Li-6400光合测定系统测定分析不同土壤水分条件下甜玉米光合光响应特征。结果表明,不同土壤水分含量对甜玉米叶片光合光响应过程的影响不同。土壤含水量为13.88%～14.50%时,随着光合有效辐射强度(PAR)的增大,净光合速率(Pn)逐渐增大至光饱和点(1 787.48～2 000.00μmol/(m^2·s),之后Pn趋于稳定;土壤含水量为11.50%～12.69%时,Pn逐渐增大至光饱和点(1 154.74～1 488.08μmol/(m^2·s),之后Pn逐渐降低,出现光抑制现象,表明土壤水分含量不低于12.69%有利于提高干热河谷甜玉米光能利用率。各光合参数具有明显的水分临界效应,但各指标的水分临界值表现不同步,其中Pn、Tr和Gs水分饱和点分别为13.88%、14.04%和15.45%,叶片水分利用效率(WUE)最高点为11.50%。这表明,土壤含水量12.69%～13.88%为甜玉米高产高效水,此时甜玉米具有较高的光合能力、高效生理用水特性以及较高的光能利用效率,是干热河谷甜玉米高产高效节水管理的关键阈值。
The objective of this study is to elucidate the adaptive mechanism of photosynthetic characters of sweet corn leaves to light intensity and soil moisture at the filling stage, and consequently to identify the threshold effects of photosynthesis to soil moisture. Soil water gradients were obtained by the balances between water provision and water consumption in the field. A Li-6400 photosynthesis system was used to measure the light response of photosynthesis of sweet corn leaves under different soil water conditions. Under the soil moisture from 13.88% to 14.50%, the net photosynthetic rate（Pn） first increased to the light saturation points of Pn [1 787.48-2 000.00 μmol/（m^2·s）] and then became stable with increasing photosynthetic active radiation（PAR）. While Pn first increased to the light saturation points of Pn[1 154.74-1 488.08 μmol/（m^2·s）] and then decreased with increasing PAR under the soil moisture range from 11.50% to 12.69%, photo-inhibition was observed in this range. Light energy use efficiency was improved, when the soil moisture was above 12.69%. Photosynthetic parameters had clear thresholds of soil moisture, but their thresholds were different. The water saturation points of Pn, Tr and Gs was 13.88%, 14.04% and 15.45%, respectively, and the water efficiency point of WUE was 11.50%. In conclusion, soil moisture range from 12.69% to 13.88% was classified as the intervals of high productivity and high efficiency. In this range, sweet corn had high photosynthetic capacity, efficient physiological characteristics for water consumption and high light energy use efficiency. This soil water content range met sweet corn production with high productivity and high efficiency in the dry-hot valley.
作者
李建查
孙毅
赵广
潘志贤
张雷
岳学文
范建成
王艳丹
何光熊
樊博
方海东
LI Jiancha;SUN Yi;ZHAO Guang;PAN Zhixian;ZHANG Lei;YUE Xuewen;FAN Jiancheng;WANG Yandan;HE Guangxiong;FAN Bo;FANG Haidong(Hot Region Eco-agriculture Research Institute,Yunnan Academy of Agricultural Sciences,Yuanmou,Yunnan 651300,China;Yunnan Institute of Water Resource and Hydropower Research,Kunming,Yunnan 650228;Key Laboratory of Mountain Haz-ards and Earth Surface Processes,Chinese Academy of Sciences,Chengdu,Sichuan 610041,China)
出处
《热带作物学报》
CSCD
北大核心
2018年第11期2169-2175,共7页
Chinese Journal of Tropical Crops
基金
云南省重点新产品开发计划项目“滇中高原特色节水农业水肥高效利用技术研究与示范”(No.2015BB019)
云南省基础研究计划项目“膜下滴灌对干热河谷土壤团聚体稳定性的影响机制”(No.2017FD207)
关键词
干热河谷
光合生理
土壤水分
光响应
dry-hot valley
photosynthetic physiological characters
soil moisture
light response
