Cuticle conductance (g_cw) can bias calculations of intercellular CO₂ concentration inside the leaf (C_i) when stomatal conductance (g_sw) is small. We examined how the light induction of photosynthesis impacts calculations by directly measuring C_i along with standard gas exchange in sunflower and tobacco leaves. When photosynthesis was induced from dark to saturating light (1200 μmol m^-2 s^-1 PAR) the calculated C_i was significantly larger than measured C_i and the difference decreased as g_sw increased. This difference could lead to over-estimation of rubisco deactivation by limited CO₂ supply during early induction of photosynthesis. However, only small differences in C_i were observed during the induction from shade (50 μmol m^-2 s^-1 PAR) because g_sw was sufficiently large. The induction from dark also allowed robust estimations of g_cw when combined with direct C_i measurements. These g_cw estimates succeeded in correcting the calculation, suggesting that the cuticle was the major source of error. Despite a technical restriction to amphi-stomatous leaves, the presented technique has a potential to provide insights into the cuticle conductance on intact stomatous leaf surfaces.

中文翻译：

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光合作用的光诱导过程中的气孔叶片表面角质层电导率的可靠估计。

当气孔导度（g _sw）较小时，表皮电导（g _cw）会使叶片内部细胞间CO ₂浓度（C _i）的计算产生偏差。我们通过直接测量C _i以及向日葵和烟草叶片中的标准气体交换，研究了光合作用的光诱导如何影响计算。当从黑暗到饱和光（1200μmolm ^-2 s ^-1 PAR）诱导光合作用时，计算出的C _i显着大于测得的C _i，并且随着g _sw增加。在光合作用的早期诱导过程中，这种差异可能会由于有限的CO ₂供应而导致Rubisco失活的高估。但是，由于g _sw足够大，因此在从阴影（50μmolm ^-2 s ^-1 PAR）诱导过程中，仅观察到C _i的微小差异。从黑暗诱导也是允许的鲁棒估计克_顺当与直接结合Ç_我测量。这些g _cw估计成功纠正了计算，这表明角质层是错误的主要来源。尽管对两亲口叶有技术上的限制，但所提出的技术仍有潜力为完整的口叶表面上的表皮电导提供洞察力。