大叶女贞抗寒性及冬季叶片相对电导率变化研究

以大叶女贞不同树龄、不同抗寒性或不同长势的植株叶片为材料,于2011年11月上旬至2012年3月中旬的每一节气内分别采样,测定叶片相对电导率,并在2012年4月初对每一采样树冬季受冻情况进行调查。结果表明:不同树龄及不同抗寒性或长势的植株冬季叶片相对电导率具有不同的变化规律,相对电导率变化曲线可分为4种:"直线型"抗寒性最强,"凹曲线型"抗寒性较强,"抛物线型"抗寒性略强,"半抛物线型"抗寒性差。大叶女贞在相对电导率达到89.15%时,仍未损害细胞膜的渗透调节能力。树龄是影响抗寒性的重要因素,22~25年生优树冬季抗寒性最强,22~25年生普通树次之,10~12年生优树抗寒性亦略强,10~12年生普通树抗寒性一般,10年以上受冻树抗寒性差,2年生苗抗寒性最差。

Cold Resistance and Change of Relative Leaf Conductivities of Ligustrunlucidum Ait in Winter

With the leaves from the tree of different age, different cold resistance or growing state of Ligustrunlucidum Ait as the study materials, relative leaf conductivities were measured in every solar term from the early November, 2011 to the middle of March,2012, and frozen injury of every sampling tree was investigated in the early April,2012. The results showed that change rules of relative leaf conductivities in different samples were different. The change curves were divided 4 types: "linear type" was the strongest in cold resistance, "concave curve type" was the second, "parabola type" was the third, "semi-parabola type" was the worst. osmotic regulation of cell membrane was not harmed even though the relative leaf conductivity had reached 89.15%. Tree-age had the most important influence on cold resistance. The cold resistance of plants: superior trees of 22~25 years old were the strongest, common trees of 22~25 years old were the second, superior trees of 10~12 years old were the general, the frost susceptible trees over 10 years old were weak, the shoot of 2 years old were the worst.