不同遮阴处理对多花黄精生理生长的影响

以2年生块茎生长而成的多花黄精植株为试验材料，以全光照为对照，测定轻度、中度、重度遮阴处理对其生长及部分生理生化指标的影响，分析了多花黄精对遮阴处理的生理响应特征。结果表明：随着遮阴强度的增大即减少透光率，多花黄精的块、根、叶生物量呈减少的趋势，茎生物量呈增加的趋势，重度遮阴时，其块、叶、根、茎鲜质量分别比CK减少了42.90%、44.67%和81.82%和增加了36.36%。遮阴能够显著改变多花黄精叶片叶绿素a、叶绿素b含量，但对其叶片类胡萝卜素含量和叶绿素a/b值的影响不显著；叶片可溶性糖和可溶性蛋白含量呈先升高后降低的趋势，且均以中度遮阴处理最高，重度遮阴处理最低，最大值是最小值的1.63和1.21倍；叶片游离脯氨酸、丙二醛、相对电导率、超氧化物歧化酶、过氧化物酶和过氧化氢酶活性呈先降低后升高的变化趋势，且中度遮阴处理时，分别比对照减少了24.13%、57.00%、6.69%、32.94%、44.94%和47.49%。因此，多花黄精在中度遮阴处理下会通过调节丙二醛含量、抗氧化酶活性和渗透调节物质等进行适应性生长。

Growth and Physiological Characteristics of Polygonatum cyrtonema Under Different Shading Treatments

In this study, Polygonatum cyrtonema with two-year tubers growth was selected as the research materials. Moreover, the full light (control), light shading, medium shading, and heavy shading treatments were set up to study the changes in physiological and biochemical indicators of P. cyrtonema. The results showed that with the increase of shading intensity, resulting in the reduced light transmittance, the biomass of blocks, roots and leaves of P. cyrtonema exhibited a decreasing trend, but the stem bimoass displayed an increasing trend. Under the heavy shading treatment, the fresh weight of blocks, leaves, roots and stems of P. cyrtonema decreased by 42.90%, 44.67% and 81.82% and increased by 36.36%, respectively, compared with the control treatment. The chlorophyll a and chlorophyll b contents in the leaves of P. cyrtonema were significantly changed under different shading treatments, but the carotenoid content and the value of chlorophyll a/b in the leaves were not significant changed. In addition, the contents of soluble sugar and soluble protein in the leaves increased at first and then decreased, and the highest and the lowest contents were observed in medium shading treatment and heavy shading treatment, respectively. The maximum value was 1.63 and 1.21 times of the minimum value. The activities of free proline, malondialdehyde (MDA), relative conductivity, superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) in leaves showed a trend of decreasing first and then increased. Under the medium shading treatment, the activities were 24.13%, 57.00%, 6.69%, 32.94%, 44.94% and 47.49% lower than those of the control treatment, respectively. In summary, the results indicate that P. cyrtonema can grow adaptively under medium shading treatment by regulating MDA content, antioxidant enzyme activities and osmotic regulatory substances.