Despite its major role in global isoprene emission, information on the environmental control of isoprene emission from tropical trees has remained scarce. Thus, in this study, we examined the relationship between parameters of G-93 isoprene emission formula (C_T1, C_T2, and α), growth temperature and light intensity, photosynthesis (ɸ, P_max), isoprene synthase (IspS) level, and 2-C-methyl-d-erythritol 4-phosphate (MEP) pathway metabolites using sunlit and shaded leaves of four tropical trees. The results showed that the temperature dependence of isoprene emission from shaded leaves did not differ significantly from sunlit leaves. In contrast, there was a lower saturation irradiance in shaded leaves than in sunlit leaves, the same as temperate plants. The photosynthesis rate of shaded leaves showed lower saturation irradiance, similar to the light dependence of isoprene emission. In most cases, the concentration of MEP pathway metabolites was of lower tendency in shaded leaves versus in sunlit leaves, whereas no significant difference was noted in IspS level between sunlit and shaded leaves. Correlation analysis between these parameters found that C_T1 of the G-93 parameter was positively correlated with the concentration of DXP and DMADP, whereas C_T2 correlated with the concentration of MEP and the average air temperature for the past 48 h. Similarly, α closely associated with the initial slope (ɸ) of photosynthesis rate, and the basal emission factor is also linked to the photon flux of past days. These results suggest that growth conditions may control the temperature dependence of isoprene emission from tropical trees via the changes in the profiles of MEP pathway metabolites, causing alteration in the parameters of the isoprene emission formula.

尽管它在全球异戊二烯排放中发挥着重要作用，但关于热带树木异戊二烯排放的环境控制信息仍然很少。因此，在本研究中，我们研究了 G-93 异戊二烯发射公式参数（C _T1、C _T2和 α）、生长温度和光照强度、光合作用（ɸ、P _max）、异戊二烯合酶 (IspS) 水平之间的关系, 和 2-C-甲基-d-赤藓糖醇 4-磷酸 (MEP) 途径代谢物使用四棵热带树木的阳光照射和遮荫叶子。结果表明，遮荫叶片的异戊二烯排放的温度依赖性与阳光照射的叶片没有显着差异。相比之下，阴影叶片的饱和辐照度低于阳光照射的叶片，与温带植物相同。阴影叶片的光合作用速率显示出较低的饱和辐照度，类似于异戊二烯发射的光依赖性。在大多数情况下，与阳光照射的叶子相比，遮荫叶中 MEP 途径代谢物的浓度较低，而阳光照射和遮荫叶之间的 IspS 水平没有显着差异。这些参数之间的相关性分析发现，C _T1G-93 参数与 DXP 和 DMADP 的浓度呈正相关，而C _T2与 MEP 的浓度和过去 48 小时的平均气温相关。同样，α与光合速率的初始斜率 ( ɸ )密切相关，基础排放因子也与过去几天的光子通量有关。这些结果表明，生长条件可能通过 MEP 途径代谢物谱的变化来控制热带树木异戊二烯排放的温度依赖性，从而导致异戊二烯排放公式参数的改变。