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将春麦“京红五号”风干种子放在不同相对湿度下,使种子含水量依次调整到9.9%至21.1%。用1—3万伦的~(60)Co—γ射线辐照上述种子。以苗高下降做为损伤的指标来比较不同含水量的种子的辐照敏感性,以及由于贮存种子环境的相对湿度对种子水分的影响而造成的辐射损伤的差异。随着照射量的增加,辐射损伤是加重的。但在1.5万至3万伦内,各照射量的苗高损伤随含水量变化的曲线却形状相似。在低相对湿度下,种子含水量下降,当含水量达13%以下时,辐射敏感性很强。同样,当环境相对湿度过高而使种子含水量达19%以上时,辐射敏感性也很强。只有当含水量在14%至加%时,辐射敏感性才较弱。此时,辐射损伤的变化受照射条件影响较小。试验结果表明:贮存种子环境的相对湿度的变化所引起的种子水分的改变是造成以往一些辐射生物学效应试验不能重复的原因之一。造成种子水分所引起的辐射敏感性差异的原因,一般认为是由于氧效应所致。
The spring wheat “Jinghong 5 ” air dried seeds placed in different relative humidity, the seed moisture content in turn adjusted to 9.9% to 21.1%. The seeds were irradiated with 1-3000 Lun ~ (60) Co-gamma rays. The shoot height reduction was used as an index to compare the radiation sensitivity of seeds with different water content and the difference of radiation damage due to the influence of the relative humidity of stored seed environment on seed moisture. Radiation damage is aggravated with the increase of exposure dose. However, in the range of 15,000 to 30,000 Lun, the curves of seedling height damage with water content varied with the similar shapes. At low relative humidity, seed moisture content drops, when the water content of up to 13%, the radiation sensitivity is strong. Similarly, the radiation sensitivity is also strong when the relative humidity of the environment is too high for the seed to have a water content of more than 19%. Radiation sensitivity is weaker only when the water content is between 14% and%. At this point, the change of radiation damage is less affected by the irradiation conditions. The results showed that the change of the seed moisture caused by the change of the relative humidity of the storage seed environment was one of the reasons that some previous experiments on radiobiological effects could not be repeated. The reason for the difference in the radiation sensitivity caused by the seed moisture is generally believed to be due to the oxygen effect.