不同光强下北细辛的光合特性及有效成分差异研究

Photosynthetic characteristics and active ingredients differences of Asarum heterotropoides var. mandshuricum under different light irradiance

研究4种光照强度下,北细辛在展叶期、花期、果初期的叶绿素含量、比叶重、光合速率、环境因子日变化曲线及其有效成分含量,分析光合速率与环境因子的相互关系。结果表明,展叶期,全光照条件下,Chla/Chlb为3. 11,接近阳生植物的特征,在遮荫条件下,Chla/Chlb均小于3. 0,Chla,Chlb以及Chl(a+b)含量随光照强度减弱而减小(P<0. 05)。随着生长继续,Chla,Chlb,Chl(a+b)含量随光照强度减弱而显著增加(P<0. 05),而Chla/Chlb随光照强度减弱而显著减小(P<0. 05)。3个物候期的比叶重值均随光照强度减弱而显著减小(P<0. 05)。展叶期和花期,全光照下的全天净光速率平均值明显大于其他光照强度下的,而果初期,全光照条件下的则小于50%,28%全光照下的,但大于12%全光照下的。全光照条件下,展叶期、花期、果期的光合速率最大值出现在8:30—9:00,最小值均出现在14:00—14:30且果期的净光合速率为负值,光合抑制严重。50%,28%,12%全光照下,花期和果期的净光合速率最大值均出现在10:30左右,最小值出现在12:20—12:50。全光照、50%,28%全光照条件下,净光合速率与光合有效辐射、胞间二氧化碳浓度间无显著相关性(P<0. 05),而与环境温度、叶片与空气间水蒸气压亏缺、气孔导度以及大气相对湿度呈显著负相关(P<0. 05),仅12%全光照下的净光合速率与光和有效辐射有显著相关性。4种光照强度下,挥发油质量分数分别是1. 46%,2. 16%,1. 56%,1. 30%,醇溶性浸出物质量分数分别是23. 44%,22. 45%,22. 18%,21. 12%,细辛脂素质量分数分别是0. 286%,0. 291%,0. 279%,0. 252%。4种光照强度下,挥发油特征成分基本相同,仅有极少的组分类别及含量存在差异。

Chlorophyll content,leaf mass to per area,net photosynthetic rate and bioactive ingredients of Asarum heterotropoides var.mandshuricum,a skiophyte grown in four levels of solar irradiance were measured and analyzed in order to investigate the response of photosynthetic capability to light irradiance and other environmental factors.It suggested that the leaf mass to per area of plant was greatest value of four kinds of light irradiance and decreasing intensity of solar irradiance resulted in the decrease of leaf mass to per area at every phenological stage.At expanding leaf stage,the rate of Chla and Chlb was 3.11 when A.heterotropoides var.mandshuricum grew in full light irradiance which is similar to the rate of heliophytes,however,the rate of Chla and Chlb was below to 3.0 when they grew in shading environment.The content of Chla,Chlb and Chl(a+b)was the greatest value of four kinds of light irradiance and decreasing intensity of solar irradiance resulted in its decreasing remarkably(P<0.05).The rate of Chla and Chlb decreased but the content of Chla,Chlb and Chl(a+b)increased gradually with continued shading.The maximum value of photosynthetically active radiation appeared at 10:00-12:00 am in a day.The maximum value of net photosynthetic rate appeared at 8:30-9:00 am and the minimum value appeared at 14:00-14:30 pm at each phenological stage if plants grew in full sunlight.However,when plants grew in shading,the maximum value of net photosynthetic rate appeared at about 10:30 am and the minimum value appeared at 12:20-12:50 pm at each phenological stage.At expanding leaf stage and flowering stage,the average of net photosynthetic rate of leaves in full sunlight was remarkably higher than those in shading and it decreased greatly with decreasing of irradiance gradually(P<0.05).However,at fruiting stage,the average of net photosynthetic rate of leaves in full sunlight was lower than those in 50%and 28%full sunlight but higher than those in 12%full sunlight.All photosynthetic diurnal variation parameters of plants measured in four kinds of different irradiance at three stages were used in correlation analysis.The results suggested that no significant correlation was observed between net photosynthetic rate and photosynthetically active radiation,and significant negative correlation was observed between net photosynthetic rate and environmental temperature as well as vapor pressure deficit expect for 12%full sunlight.Positive correlation was observed between net photosynthestic rate and relative humidity expect for 12%full sunlight.Significant positive correlation was observed between net photosynthetic rate and stomatal conductance in the four light treatments.Only,in 12%full sunlight,the net photosynthetic rate was significantly related to photosynthetically active radiation rather than related to environmental temperature,vapor pressure deficit and relative humidity.In each light treatment,a significant positive correlation was observed between environmental temperature and vapor pressure deficit,relative humidity as well as stomatal conductance.Volatile oil content was 1.46%,2.16%,1.56%,1.30%respectively.ethanol extracts was 23.44%,22.45%,22.18%,21.12%respectively.Asarinin content was 0.281%,0.291%,0.279%and 0.252%respectively.The characteristic components of Asarum volatile oil of plant in different light treatments did not change significantly among different groups.