微波辐照对苜蓿种子储存后发芽和幼苗生长生理特性的影响

为探明微波辐照对苜蓿种子在数年后的发芽及幼苗生长生理特性的影响，以室温下储存2 a的紫花苜蓿种子进行发芽和盆栽试验，测定种子发芽率、胚根伸长量、幼苗生长高度、单株结瘤数、固氮酶活性、叶绿素含量及叶绿素荧光特性等指标。结果表明：发芽15 d时，各处理的总发芽率均高于对照，且随着辐照时间的延长而降低；发芽11 d 时，各处理的胚根平均长度均低于对照；40 s辐照处理种子形成的幼苗高度、单株结瘤数及幼苗鲜重和干重均高于对照；幼苗根瘤的固氮酶活性均显著低于对照 （P<0.05），叶片的叶绿素含量在辐照时长为10 s时最大；各处理叶片F₀和F_v/F_m的变化说明，在室温下储存2 a的辐照苜蓿种子形成幼苗后叶片的光能转化效率仍受到一定的胁迫。

Effect of Microwave Irradiation on Germination and Seedling Growth Physiological Characteristics of Alfalfa Seeds After Storage

In order to study the effect of microwave irradiation on germination and growth physiological characteristics of seeds that stored for years, the irradiated alfalfa seeds that stored at room temperature for 2 years were used to conduct the germination and pot culture tests, and the germination rate, radicle elongation, growth height, individual nodule, nitrogenase activity, chlorophyll content and chlorophyll fluorescence parameters were measured. On the 15th day of germination, the germination rates of all the treatments are higher than that of the control, which decrease with the elongation of time. On the 11st day of germination, the radicle length of all the treatments is lower than that of the control. Growth height, individual nodule, fresh weight and dry weight for the 40 s irradiation treatment are higher than that of the control. Nitrogenase activity of all the treatments is lower than that of the control (P<0.05). The chlorophyll content reaches its maximum when being irradiated for 10 s, and the variation for F₀ and F_v/F_m of all treatments indicates that the light conversion efficiency of the leaves derived from the irradiated alfalfa seeds that stored for 2 a at room temperature is still relatively stressed.