不同土壤水分含量对黄精生长及多糖含量影响

The Effect on Growth of Polygonatum sibiricum Under Different Soil Moisture Content

目的:研究3个水分条件对2年生黄精的生长、光合特性及干物质和多糖积累的影响。方法:采用盆栽控水实验的方法,测定适宜水分(75%田间持水量)、中度干旱(50%田间持水量)和重度干旱(35%田间持水量)水分条件下黄精的形态指标、干物质积累、多糖含量和光合作用指标。结果:3个水分条件下,黄精的株高、茎粗、叶长、叶宽等形态指标的生长动态均呈"S"型;水分含量显著影响黄精根茎、茎、叶的生长,干物质和多糖积累;中度干旱水分条件对干物质和多糖含量的影响与适宜水分条件无显著性差异,但表现出更适合多糖积累的趋势;重度干旱水分条件能够促进须根的增长,但不利于黄精茎、叶、根茎的生长及干物质和多糖含量积累,且折干率和根冠比较低,同时减少根系总产量;不同土壤水分条件下,黄精叶片净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)和瞬时水分利用率(WUEi)变化规律相似,呈明显的双峰曲线,中午有明显的"午休"现象,土壤水分含量过高或过低均降低黄精对水分的利用率。结论:保持适当土壤干旱有利于黄精产量的提高,50%~75%的田间持水量更有利于黄精的生长发育及药用有效成分的积累。

Objective： To study the effect on plant growth,photosynthetic characteristics,dry matter and polysaccharide accumulation under three soil moisture conditions in two-years old Polygonatum sibiricum. Methods： Water-controlled pot experiment method was used to study the effect on morphological parameter,dry matter and polysaccharide accumulation,photosynthetic characteristics of two years-old rhizomes of Polygonatum sibiricum under the suitable soil moisture（ 75% of soil field capacity）,moderate dry soil moisture condition（ 50% of soil field capacity） and severe dry soil moisture conditions（ 35% of soil field capacity）,respectively. Results： The dynamic growth of the morphological indexes presented an＂S＂model under three kinds of moisture conditions,such as plant height,stem diameter,leaf length and leaf width. Water content significantly influenced the plant growth including rhizome,stem and leaves and dry matter,polysaccharide accumulation. The influence of moderate dry soil moisture condition on dry matter and polysaccharide content was not different with the suitable soil moisture,but it showed a tendency to be more suitable for the accumulation of polysaccharides. Although severe dry soil moisture condition could promote new fiber improvement,but it was bad for the stem,leaf and rhizome growth and the accumulation of dry matter and polysaccharide,and the drying rate and root shoot ratio was lower,and reduced the root production. The variation of the net leaf photosynthetic rate（ Pn）,stomatal conductance（ Gs）,transpiration rate（ Tr） and instantaneous water use efficiency（ WUEi） were similarly under different soil moisture conditions,and presented a clear bimodal curve accompanied an obvious＂lunch break＂phenomenon at noon. The water use efficiency of Polygonatum sibiricum was reduced when the soil water content was too high or too low. Conclusion： Keeping proper soil drought is beneficial to the improvement of Polygonatum sibiricum production,and 50% - 75% of soil field capacity is more advantageous to the growth of Polygonatum sibiricum and medicinal active ingredients accumulation.