不同处理对脂松苗木自然越冬过程中生理指标和越冬伤害的影响

Effects of Different Treatments on the Physiological Indicators and Winter Injury of Red Pine Seedlings during Natural Overwintering

研究不同处理(秋季涝渍、秋季变温、冬季遮荫)对2年生盆栽脂松苗木在自然越冬过程中针叶的膜脂过氧化作用、抗氧化酶活性和有机渗透调节物质的动态变化,并结合越冬伤害调查分析不同处理对其越冬伤害的影响。结果表明:在自然越冬期间各处理脂松苗木针叶的电导率、丙二醛(MDA)质量摩尔浓度、脯氨酸质量分数及过氧化物酶(POD)活性均表现为先升高后降低的变化趋势,可溶性糖质量分数表现为先升高后下降再升高,超氧化物歧化酶(SOD)活性在整个越冬期间总体的变化呈"M"形状;说明脂松苗木能够快速应对环境变化,通过调整生理代谢使叶片中快速积累渗透调节物和激活抗氧化酶防止氧自由基积累抑制膜脂过氧化,提高了脂松苗木组织内部的抗氧化能力、增强抗寒能力,从而在冬季低温变化过程中起到保护作用;各处理苗木均有不同程度的越冬伤害现象发生,冬季遮荫、秋季涝渍和秋季变温处理在3月份分别有10%、44%和100%的苗木发生越冬伤害现象,5月份的调查中分别有2%、10%和16%的苗木死亡。综合分析可见,脂松苗木具有较强的抗寒性,秋季骤然变温或秋季涝渍均会导致苗木在自然越冬过程中发生越冬伤害,而冬季适当遮荫有利于脂松安全越冬。

We studied the dynamic variations of membrane lipid peroxidation, antioxidant enzyme activity and organic osmoregu- lation substance in needles for two-year-old pot cultivation red pine seedlings under different treatments （ autumn waterlog- ging, autumn temperature fluctuation and winter shading） during natural overwintering. We investigated and analyzed the effects of different treatments on the winter injury. During natural overwintering, in red pine seedling needles under each treatment, the conductivity, the content of MDA, the content of proline and the activity of POD display the variation trend of increasing first and then declining, the content of soluble sugar shows increase-decline-increase, the activity of SOD re- veals the overall variation shape of ＂M＂ during the whole overwintering. The red pine seedlings are able to rapidly respond to environment change. Osmoregulation substances accumulate rapidly in lead blades by regulating physiological metabo- lism and the accumulation of oxygen free radicals are prevented from inhibiting membrane lipid peroxidation by activating antioxidant enzyme to increase the internal antioxidant ability of red pine seedlings and strengthen the ability to resist cold with the protective effect in winter low temperature change. The winter injury phenomenon can occur in seedlings under each treatment. In March, under winter shading, autumn waterlogging and autumn temperature fluctuation, the winter in- jury occurs in 10% , 44% and 100% of seedlings, respectively. In May, there are 2% , 10% and 16% of died seedlings, respectively. Therefore, the seedling needles have stronger cold resistance, and abrupt temperature fluctuation in autumn or autumn waterlogging will lead to winter injury in seedlings during natural overwintering. However, appropriate shading in winter is favourable for safe overwintering of red oine.