白及对光的生物学响应研究

Study on the Biological Response of Bletilla striata to Light

目的:筛选出白及对光的最佳生物学响应条件。方法:通过遮阴度为80%、60%、30%、全光照(CK)4个不同遮阴处理实验,研究不同遮阴处理下对白及植株性状、光合特性指标和多糖的影响。结果:(1)株高、叶长、叶宽随着遮阴度的增加而增加,遮阴度为60%时,茎最粗,根数最多,叶片、块茎、须根干重达到最大。(2)叶绿素a、b的含量随遮阴度的增加而增加,叶绿素a/b值随遮阴度的增加而减小,使白及在弱光条件下充分吸收散射光,仍保持较强的光合能力。60%遮阴处理白及净光合速率(Pn)最大,显著高于CK处理,并且随着光照强度的增加,气孔导度(Gs)呈下降趋势,而蒸腾速率(Tr)与Gs变化较为一致,胞间CO_(2)浓度(Ci)呈现先降低后增加的趋势;Pn与Ci呈极显著负相关,Gs与Tr呈显著正相关。(3)在采收期,多糖得率在60%遮阴处理下最大,而白及粗多糖含量在各个水平下差异不明显。结论:白及有较强的耐阴性,在生产上对其进行60%遮阴,更有利于获得品质优良的白及。

Objective:To screen out the best biological response conditions of Bletilla striata to light.Methods:Through four different shading treatment experiments with shading degrees of 80%,60%,30%,0%(CK),the effects of different shading treatments on Bletilla striata plant traits,photosynthetic characteristics and polysaccharides were studied.Results:(1)As the degree of shading increases,the plant height,leaf length and leaf width increased.Under the 60%shading degree,the stem was the thickest and the root number was the most,the dry weights of leaves,tubers and fibrous roots reached the maximum.(2)The contents of chlorophyll a and chlorophyll b increased with the increase of shading degree,the ratio of chlorophyll a and chlorophyll b decreased with the increase of shading degree,which made Bletilla striata fully absorb scattered light under low light conditions and still maintain strong photosynthesis ability.The photosynthetic rate(Pn)of Bletilla striata was the highest in 60%shading treatment,which was significantly higher than CK treatment,and stomatal conductance(Gs)showed a downward trend with the increase of light intensity,while transpiration rate(Tr)and Gs changed more consistently,the intercellular CO_(2) concentration(Ci)appeared to decrease first and then increase.Pn was significantly negatively correlated with Ci,and Gs was significantly positively correlated with Tr.(3)Under the harvesting period,polysaccharide yield was the largest under 60%shading treatment,while the crude polysaccharide content of Bletilla striata was not significantly different at each level.Conclusion:Bletilla striata has a strong resistance to shade,in production,60%shading is more conducive to obtaining good quality Bletilla striata.