The results showed that there are no significant difference within the stomatic distribution of outer epidermis of young and aged stem and aged leaf sheath in three plants ; but there are significant or very significant difference within apex , middle and base of young and aged leaves .

结果表明：三种植物的幼茎、成熟茎和成熟叶鞘外表皮的上部、中部、基部的气孔分布均无显著性差异，而幼叶和成熟叶的上、中、下部的气孔分布存在着显著性差异或极显著差异。

Under high fertilizer condition , the soil water was consumed largely during the early period , therefore , the crop suffered severe drought stress during the procreation stage , and the net photosynthetic rate ( pn ) , transpiration rate ( tr ) and stomatic conductance ( gs ) of potato declined greatly .

高肥处理时,由于马铃薯植株生长旺盛,营养生长期水分消耗过大,生殖生长期土壤水分供应状况更差,作物受到严重的水分胁迫,导致气孔导度、净光合速率和蒸腾速率大幅下降.