目的:两排造口术是提高光合速率的一种潜在方法;然而,两栖类物种及其驱动因素的气孔密度的纬度梯度仍然未知。
方法:这里,486个两栖物种-位点组合的正面气孔密度(SDad)和背面气孔密度(SDab),属于32个植物家族,是从中国收集的,并计算了它们的总气孔密度(SDtotal)和气孔比(SR)。
结果:总体而言,这四个气孔性状没有显示出显著的系统发育信号。木本和草本物种之间的SDab和SDtotal没有显着差异,但木本物种的SDad和SR高于草本物种。此外,观察到SDab和SDad之间存在显著正相关.我们还发现气孔密度(包括SDab,SDad,和SDtotal)随纬度而减少,而SR随纬度而增加,温度季节性是驱动它的最重要的环境因素。此外,进化史(由系统发育和物种代表)解释的气孔性状变异比当今环境多10-22倍(65.2%-71.1%vs.2.9%-6.8%)。
结论:我们的研究扩展了我们对性状与环境关系的认识,并强调了进化史在驱动气孔性状变异方面的重要性。
OBJECTIVE: Amphistomy is a potential method for increasing photosynthetic rate; however, the latitudinal gradients of stomatal density across amphistomatous species and their drivers remain unknown.
METHODS: Here, the adaxial stomatal density (SDad) and abaxial stomatal density (SDab) of 486 amphistomatous species-site combinations, belonging to 32 plant families, were collected from China, and their total stomatal density (SDtotal) and stomatal ratio (SR) were calculated.
RESULTS: Overall, these four stomatal traits did not show significant phylogenetic signals. There were no significant differences in SDab and SDtotal between woody and herbaceous species, but SDad and SR were higher in woody species than in herbaceous species. Besides, a significantly positive relationship between SDab and SDad was observed. We also found that stomatal density (including SDab, SDad, and SDtotal) decreased with latitude while SR increased with latitude, and temperature seasonality was the most important environmental factor driving it. Besides, evolutionary history (represented by both phylogeny and species) explained about 10-22 fold more of the variation in stomatal traits than the present-day environment (65.2%-71.1% vs. 2.9%-6.8%).
CONCLUSIONS: Our study extended our knowledge of trait-environment relationships and highlighted the importance of evolutionary history in driving stomatal trait variability.