Growth acceleration of plants by UV-C rays irradiation for he comming global warming

在移栽前，用同样强度（23 μ W）的UV-C射线照射蔬菜幼苗，照射时间从0到150分钟不等。UV-C射线照射30分钟左右，植物生长量增加，照射时间越长，植物生长量越少，即对植物生长既有促进作用，又有抑制作用，本文从植物生长的逻辑斯谛理论出发，对这一现象进行了分析，阐明了环境因子作用形式之一的最佳因子的作用机理。这意味着有一个最有利于植物生长的辐照时间值，它比正常情况下更能促进植物生长。UV-C射线照射后2周左右即出现这种效应，在照射后1周左右，各处理对叶片的生长都有抑制作用，而根系活力则有所增强，这是促进生长的关键。通过水培试验证实了这一点，即在相同的抑制时间内，叶片的溶解氧消耗速率有较大幅度的增加，通过测定叶片的光合速率、蒸腾速率和气孔导度，（=光合速率/蒸腾速率）由照射前1周的低到照射后2-3周的高，通过夏季和冬季气温对辐射苗生长影响的试验，发现高温对辐射苗生长的抑制作用持续时间短于低温，夏季对辐射苗生长的促进程度大，这意味着这种利用UV-C辐射育苗的方法可能是应对全球变暖的有利措施之一。

We irradiated UV-C rays on plant seedlings of vegetable under same intensity (23 muW), changing duration from 0 to 150 minutes, just before transplant. Plants grew much more at about 30 minutes of irradiation, and less under longer irradiation, that is, plant growth were effected in both ways of acceleration and inhibition depending on duration of irradiation of UV-C rays.We considered this phenomena from point of view of the logistic theory for plant growth, and made clear the mechanism the optimum factor, one of the action form of environment elements. This means that there is the most favorable value of irradiation time for plant growth, which accelerate growth much more than the normal. Such result was appeared in two weeks after UV-C rays irradiation.As the key point of acceleration of growth, there was the inhibition of growth to leaves in every treatments during about one week after irradiation, and activity in roots was increased in the same time. We confirmed it by the hydroponic cultivation, that is, the comsumption rate of disolved oxygen increased quite large in the same duration of inhibition of leaves.Though measurements of photosynthetic rate, transpiration rate and stomata conductance, water use efficiency (= photosynthetic rate/transpiration rate) were changed greatly by UV-C rays irradiation from low in the first one week to high in the next 2-3 weeks, comparing to the non-treated vegetable.By the experiments on the effect of air temperature on growth of irradiated seedlings in summer and wingter, it was made clear that the duration of inhibition was shorter in high temperature than in lower temperature, and the degree accelerated growth in the field was higher in summer, This means that such method using UV-C rays to plant seedlings may be one of favorable methods for taking measurement against comming global warming.