农田人参叶片净光合速率日变化及其与环境因子的关系

Relationship between diurnal changes of net photosynthetic rate of farmland Panax ginseng leaves and environmental factors

【目的】明确适合农田人参生长的阴棚小气候,指导人参的规模化生产,提高经济效益。【方法】以3年生农田人参为材料,利用Li-6400便携式光合测定系统,测定了农田人参叶片净光合率和阴棚中各项环境因子指标的日变化规律,分析主要环境因子对农田人参叶片净光合速率日变化的影响,并将环境因子逐一与净光合速率进行了相关性分析。【结果】农田人参功能叶片在绿果期净光合速率为0.50~3.05μmol/(m^2·s)。一日中人参叶片净光合速率、蒸腾速率、气孔导度的日变化均呈现为上午升高,中午降低并维持在较低水平,下午逐渐降低的趋势,且上午的净光合速率要高于下午。对环境因子与净光合速率的相关性分析表明,农田人参叶片净光合速率与光量子通量密度和空气温度均呈显著正相关,相关系数分别为0.591 2和0.572 8。【结论】农田人参叶片净光合速率的日变化主要受空气温度和光量子通量密度的影响,因此在农田栽培中应注重调控阴棚中的光强和温度指标。

[Objective] This study determined the suitable shaded micro climate for growing farmland ginseng to guide ginseng scale production and increase economic benefits. [Method] Using Li-6400 porta- ble photosynthesis system, diurnal changes of net photosynthetic rate of 3-year-old farmland ginseng and environmental factors were measured. Relationships between diurnal changes of net photosynthetic rate and environmental factors were determined. [Result] The net photosynthetic rate was 0. 50- 3. 05 μmol/ （m2 ＊ s） in un-folding leaves of Panax ginseng in green fruit period. The net photosynthetic rate,stomatal conductance and transpiration rate increased in morning, decreased to a stable level at noon, and gradually decreased in afternoon. The net photosynthesis rate in morning was higher than in afternoon. The net pho- tosynthetic rate was significantly positively correlated with photo flux density （PFD） and temperature with correlation coefficients of 0. 591 2 and 0. 572 8, respectively. [Conclusion] Photo flux density and air temperature were the major environmental factors influencing diurnal changes of net photosynthetic rate. Thus, it is important to focus on light intensity and temperature for the growth of ginseng.