辐照剂量对棕榈藤种子萌发和苗木生长的影响

为确定棕榈藤的适合辐照剂量域值,以黄藤、单叶省藤、杖藤和小钩叶藤4种棕榈藤为研究对象,以种子为辐照材料,以⁶⁰CO-γ为辐射源,研究辐照剂量对4种棕榈藤种子萌发和苗木生长的影响。结果表明:以5 gy/min为剂量率、50 gy为辐照剂量步长上升时,在0~100 gy辐照剂量内,黄藤、单叶省藤、杖藤、小钩叶藤种子发芽率、茎长、根长和植株总长均随着辐照剂量的上升而呈一般显著、显著或极显著下降;当辐照剂量超过100 gy时,4个藤种的发芽率均降为0,即种子全部失活。以辐照剂量为自变量x、发芽率为因变量y拟合的一元回归方程计算表明,黄藤、单叶省藤、杖藤和小钩叶藤种子的半致死剂量分别为53.94、28.01、58.34和75 gy。研究结果显示,辐照剂量对棕榈藤的种子萌发和苗木生长具有抑制作用,其辐照剂量范围为50~100 gy。通过辐照培育高产棕榈藤品种难度较大,辐照可能更加适合以其他性状为目标的棕榈藤育种。

Effects of Irradiation Dose on Seed Germination and Seedling Growth of Rattans

To determine the appropriate irradiation dose threshold for rattan, the seeds from Daemonorops jenkinsiana, Calamus simplicifolius, C. rhabodcladus, and Plectocomia microstachys were used as material to be treated by irradiation from ⁶⁰Co-γ, with the view to studying the effect of irradiation dose on the seed germination and seedling growth of the four rattan species. The results showed that seed germination rate, stem length, root length and plant length of the four species of rattan present general, significant or very significant decrease along with the increase of irradiation dose if the dose rate was at 5 gy/min and increased with the dose of 50 gy and the dose was limited in the range of 0-100 gy. When the irradiation dose was beyond 100 gy, the seed germination rate of the four species would decrease to 0, i. e., all the seeds stop growing. The linear regression equation, simulated with irradiation dose as dependent variable x, and germination rate as the independent variable y, indicated that the half-lethal irradiation doses to the four rattan species are 53.94 gy, 28.01 gy, 58.34 gy and 75 gy, respectively. It is concluded that seed germination and seedling growth are inhibited by irradiation when the irradiation dose is in the range of 50-100 gy. This result indicates it is probably hard to cultivate fast-growing rattan mutants by irradiation, but other targeted mutants are not exclusive.