叶片吸收雾滴过程中雾滴覆盖面积的变化规律

为了给气雾培、叶面施肥以及植保机械的研究提供进一步的理论依据,研究了作物组织吸收雾滴的过程．建立了一个相对湿度为100％,温度为20 ℃的环境控制室,以蒸馏水为载体,利用Matlab图像处理技术研究了雾滴在活体植物猩猩木叶片表面不同位置其覆盖面积随时间变化的规律．首先,为了消除雾滴蒸发对试验的影响,分别用直径为23877,22992,21260 μm的雾滴来验证其蒸发率:在600 s内的蒸发率分别为14％,28％,31％．因此假设雾滴在前600 s内几乎无蒸发．之后,选取直径分别为540,340 μm的雾滴进行雾滴覆盖面积变化的研究．利用雾滴发生器将不同直径的雾滴喷射到叶面不同的位置,利用图像采集系统获得雾滴的照片,观察雾滴覆盖面积的变化情况．叶片吸收雾滴的试验表明:叶片表面不同位置覆盖面积的变化是不同的,雾滴在叶片表面的覆盖面积前期变化缓慢,到后期变化迅速,而且越往后期变化越明显;雾滴的覆盖面积越大,雾滴吸收速度越快．

Variation characters of droplet coverage area in leaf droplet water uptake process

In order to provide useful data for theoretical investigations into aeroponics,foliar fertilization and plant protection equipment development,the process of plant tissue absorbing droplet was conducted.A chamber with controlled environment(100% relative humidity and 20 ℃ temperature) was designed to observe the change in the coverage area of a droplet on a leaf with time.To eliminate the influence of droplet evaporation,three droplets respectively with 238.77,229.92 and 212.60 μm dia-meters were employed to verify droplet evaporation rates.The evaporation rates of three droplets were 1.43%,2.8% and 3.1% at the interval of 600 s respectively.Two droplets with the diameters of 340 and 540 μm were employed to conduct the droplet foliage uptake experiments.The experimental outcomes suggest that the change rate of coverage area of droplet depends on the position where a droplet is dripped and the time elapsed when the droplet is on the foliage.