干旱胁迫条件下冷型小麦灌浆结实期的农田热量平衡

Heat balance of cold type wheat field at grain-filling stage under drought stress condition

冷型小麦具有代谢功能较好、活力较旺盛、抗早衰能力较强的特征,因而,培育出越来越多的冷型小麦并将其推向生产对于小麦的高产、稳产十分重要。在干旱频繁出现的今天,小麦生产受到了极大的影响,因而研究干旱胁迫下冷型小麦的农田热量平衡,对明了冷型小麦农田小气候的形成机理、改善农田小气候环境具有重要意义。通过对相关气象要素和小麦生态指标的测定,研究了干旱胁迫条件下冷型小麦灌浆结实期的农田热量平衡,揭示了冷型小麦对干旱胁迫的适应机制。结果表明:①冷型小麦农田净辐射较暖型小麦偏低16.35—47.57W/m2,但经统计检验,两者差异未达显著水平。②活动层内0.2m—2/3株高和2/3株高—冠顶冷型小麦的潜热通量较暖型小麦分别偏高29.09—48.61W/m2和47.41—134.89W/m2,湍流热通量分别偏低12.48—62.57W/m2和29.37—85.81W/m2;活动层与大气之间的潜热通量,冷型小麦较暖型小麦偏高50.30—124.20W/m2,湍流热通量偏低30.50—102.40W/m2。③冷型小麦的土壤热通量比暖型小麦偏低24.60—65.19W/m2。④冷型小麦加热植株体的热量QA+QT较暖型小麦偏低43.70W/m2。在干旱胁迫条件下,冷型小麦田的能量分配创造出了冷湿的小气候环境,有利于小麦的生长发育和产量的提高。

Through studies on the canopy temperature and some other traits of wheat for more than 20 years,it was verified the presence of cold type wheat,which could maintain lower canopy temperature continuously and stably during its grain-filling stage,was discovered with the characteristics of better metabolism and vigor,and stronger tolerance to early senescence,especially for its strong adaptability to stress conditions,which posed an important role of cold type wheat in improving and stabilizing wheat production.With the advent of frequent drought stress,wheat production was affected greatly;therefore,investigating the heat balance in cold type wheat field under drought condition would benefit the understanding and improvement of formation mechanism of cold type wheat field environment and promote its application in wheat production.The experiments were conducted under rainout shelters for three continuous growth seasons to investigate the differences in canopy temperature,air temperature,air humidity,wind speed,net radiation flux density,latent heat flux,turbulent heat flux,soil heat flux and energy heating leaf blade and stem between cold and warm type wheat materials to investigate the heat balance in cold type wheat field at grain-filling stage under drought stress and to reveal the adaptation mechanism of cold type wheat to drought stress.The results showed that,①The net radiation flux density of cold type wheat is 16.35-47.57W/m2 lower than that of warm type one,but the difference was not significant.②The latent heat flux measured at 0.2 m above ground to 2/3 plant height and 2/3 plant height to the canopy in rows of cold type wheat was 29.09-48.61 W/m2 and 47.41-134.89 W/m2 higher than that of warm type wheat,respectively;but the turbulent heat flux of cold type wheat was 12.48-62.57 W/m2 and 29.37-85.81W/m2 lower than that of warm type wheat,respectively.The latent heat flux between the active layer and atmosphere of cold type wheat was 50.30-124.20 W/m2 higher than that of warm type wheat,but the turbulent heat flux poured into the atmosphere of cold type wheat was 30.50-102.40 W/m2 less than that of warm type wheat.③The soil heat flux of cold type wheat was 24.60-65.19 W/m2 lower than that of warm type wheat.④The energy heating leaf blade and stem of cold type wheat was 43.70 W/m2 lower than that of warm type wheat.Under drought condition,heat distribution in cold type wheat field created cold and humid micro-climate environment through net radiation increased to latent heat and reduced to soil heat and energy heating leaf blade and stem,which benefited the growth and yield improvement of wheat under drought condition and improved its adaptability in stress conditions,especially for those grown in arid and semi-arid areas.