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为进一步明确玉米叶-气温差和叶温差日变化特征及其对干旱的响应与品种差异,通过人工旱棚控水,设置充分供水、轻度胁迫、中度胁迫和重度胁迫4个土壤水分处理,研究5个玉米杂交种功能叶片表面温度及环境光温湿度日周期变化特征,比较分析了不同生育时期叶-气温差和叶温差的变化特性及其与环境因子的关系。结果表明:1)叶-气温差是衡量玉米水分丰缺状况的1项有效指标。在充足供水条件下玉米叶-气温差较为稳定,维持在-4.0~-1.0℃范围内,干旱胁迫下均表现出升高趋势,重度胁迫与充足供水处理之间的差值可达5℃以上,且多出现于12:00—16:00;2)叶温差日变化表现为先升高后降低趋势,并随着干旱胁迫程度的加大而增大;3)干旱处理叶-气温差与光合有效辐射和大气温度的相关性高于空气湿度和饱和水汽压差,均达到显著或极显著水平;4)杂交种间叶-气温差差异不显著,叶温差则差异显著,但不同时间和不同生育时期表现不一致。总之,梯度土壤干旱胁迫导致了叶-气温差和叶温差的逐级升高,叶-气温差可有效反映玉米植株水分丰缺状况,而叶温差在玉米抗旱品种筛选方面的意义尚需进一步研究。
In order to further clarify the diurnal variation characteristics of leaf temperature-temperature difference and leaf temperature in maize and its response to drought and the difference of cultivars, four soil moisture treatments, including full water supply, mild stress, moderate stress and severe stress, , The characteristics of leaf surface temperature and ambient light temperature, humidity and daily cycle of five maize hybrids were studied. The variation characteristics of leaf - air temperature difference and leaf temperature difference at different growth stages and their relationship with environmental factors were analyzed. The results showed that: 1) leaf-air temperature difference is a valid indicator to measure the water deficit status of maize. Under sufficient water supply conditions, the leaf temperature difference between maize and leaves was relatively stable within the range of -4.0 ~ -1.0 ℃, and both showed an increasing trend under drought stress. The difference between severe stress and adequate water supply could reach above 5 ℃ , And most appeared in 12: 00-16: 00; 2) The daily change of leaf temperature showed the trend of increasing firstly and then decreasing, and increasing with the degree of drought stress; 3) The correlation between photosynthetically active radiation and atmospheric temperature was higher than that of air humidity and saturated vapor pressure, both of which reached significant or extremely significant level. 4) The difference of leaf-temperature difference between hybrids was not significant, while the difference of leaf temperature was significant, but at different times Different performance during different stages of growth. In conclusion, the gradient soil drought stress led to the gradual increase of the leaf-air temperature difference and the leaf temperature difference. The leaf-air temperature difference could effectively reflect the water deficit status of maize plants. However, the significance of the leaf temperature difference in the selection of maize drought-tolerant cultivars still needs further study .