在高相对空气湿度(RH)下形成的气孔随着叶片干燥而减少;这种影响因基因型而异。我们在这里量化了每个气孔响应特征对高RH生长的植物的较高水分损失的贡献,并评估了响应特征与气孔大小种内变化之间的关系。气孔大小(长度乘以宽度),密度和对干燥的响应性,在中等(60%)或高(85%)RH下生长的十个玫瑰品种中分析了孔尺寸。还评估了生长条件下的叶片形态成分和蒸腾作用。高生长RH导致面积更大的叶片更薄(11%)。在任一RH下,白天和夜间蒸腾作用都具有很强的正遗传相关性。气孔大小决定了孔面积(r=0.7),变化系数为2,作为长度和宽度成比例变化的结果。气孔的大小和密度无关。干燥后,高RH导致三个品种的蒸腾作用显着降低(6-19%),而在七个品种中,高RH扩张小叶的相对含水量(RWC)较低(29-297%)。这些小叶的RWC较低是由(a)较高(33-72%)稳定蒸腾作用和/或(b)较低(12-143%)发生这种稳定蒸腾作用的RWC引起的,取决于品种。气孔大小与这两个特征显着相关(分别为r=0.5和-0.7)。这些结果表明,气孔大小解释了玫瑰缺水时蒸腾作用调节中的许多种内变化。
Stomata formed at high relative air humidity (RH) close less as leaf dries; an effect that varies depending on the genotype. We here quantified the contribution of each stomatal response characteristic to the higher water loss of high RH-grown plants, and assessed the relationship between response characteristics and intraspecific variation in stomatal size. Stomatal size (length multiplied by width), density and responsiveness to desiccation, as well as pore dimensions were analyzed in ten rose cultivars grown at moderate (60%) or high (85%) RH. Leaf morphological components and transpiration at growth conditions were also assessed. High growth RH resulted in thinner (11%) leaves with larger area. A strong positive genetic correlation of daytime and nighttime transpiration at either RH was observed. Stomatal size determined pore area (r=0.7) and varied by a factor of two, as a result of proportional changes in length and width. Size and density of stomata were not related. Following desiccation, high RH resulted in a significantly lower (6-19%) decline of transpiration in three cultivars, whereas the relative water content (RWC) of high RH-expanded leaflets was lower (29-297%) in seven cultivars. The lower RWC of these leaflets was caused by (a) higher (33-72%) stable transpiration and/or (b) lower (12-143%) RWC at which this stable transpiration occurred, depending on the cultivar. Stomatal size was significantly correlated with both characteristics (r=0.5 and -0.7, respectively). These results indicate that stomatal size explains much of the intraspecific variation in the regulation of transpiration upon water deprivation on rose.