Abstract

This paper examined eight additional parameters relating to photosynthetic rate of Lonicera japonica Thunb. Correlation analysis, regression analysis and factor analysis were used to analyze the relationship between net photosynthetic rate (Pn) and environment factors, which included stomatal conductance (Sc), intercellular CO₂ concentration (Ci), transpiration rate (Tr), air temperature (Ta), leaf temperature (Tl), air CO₂ concentration (Ca), relative air humidity (RH), photo flux density (PFD), etc.. The results showed that the diurnal Pn of L. japonica Thunb. It may vary with double peak curves; there was no significant midday depression from June to August. The stepwise regression analysis which introduced characters into a multiple regression equation in the order in which they contribute to Pn, together with factor analysis was used to analyze the same dependence structure. The 8 causes were grouped into the basic factors which generate the dependence structure. The result suggested that high photo flux density (PFD), high Tl and low RH may result in the high Pn. Increasing Tr and PFD, accelerating the hot air flow, would be the most effective way of increasing Pn. The analysis result would assist the medicinal herb grower by adjusting environment factors level to regulate Pn of L. japonica Thunb. and improve output and quality of flower.

Key words: Lonicera japonica Thunb., environment factors, net photosynthetic rate, interrelationships.

Abbreviation

 Pn, Net photosynthetic rate; C_i, intercellular CO₂ concentration; Ca, air CO₂concentration; PFD, photo flux density; Sc, stomatal conductance; Tr, transpiration rate; Ta,air temperature; Tl, leaf temperature; RH, relative air humidity; WUE, leaf water use efficiency; ANOVA, analysis of variance.