But how SO2 induces stomatal movement and guard cell death, and which kinds of signals involved in the procedure have not been reported.
但SO2如何影响气孔运动及诱导细胞死亡，以及这些过程中涉及到的调控机制，尚未见报道。
2
The sizes of epidermis cell, the lengths of stomatal guard cells and of the terminal cells of T-hair are only quantitative characters, but not of much significances in systematics.
The lower stomatal conductance and photosynthetic rate of Paphiopedilum might partially caused by the lack of chloroplasts in the guard cell of Paphiopedilum.