Data from: Stomatal patterning is differently regulated in adaxial and abaxial epidermis in Arabidopsis

Stomatal pores in leaves mediate CO2 uptake into the plant and water loss
via transpiration. Most plants are hypostomatous with stomata present only
in the lower leaf surface (abaxial epidermis). Many herbs, including the
model plant Arabidopsis thaliana, have substantial numbers of stomata also
on the upper (adaxial) leaf surface. Studies of stomatal development have
mostly focused on abaxial stomata and very little is known of adaxial
stomatal formation. We addressed the role of leaf number in determination
of stomatal density and stomatal ratio, and studied adaxial and abaxial
stomatal patterns in mutants deficient in known abaxial stomatal
development regulators. We found that stomatal density in some genetic
backgrounds varies between different fully expanded leaves and recommend
using defined leaves for analyses of stomatal patterning. Our results
indicate that stomatal development is at least partly independently
regulated in adaxial and abaxial epidermis, as i) plants deficient in ABA
biosynthesis and perception have increased stomatal ratios, ii) the
epf1epf2, tmm and sdd1 mutants have reduced stomatal ratios, iii) erl2
mutants have increased adaxial but not abaxial stomatal index, and iv)
stomatal precursors preferentially occur in abaxial epidermis. Further
studies of adaxial stomata can reveal new insights into stomatal form and
function.

叶片气孔可介导植物对二氧化碳的吸收以及蒸腾作用引发的水分散失。绝大多数植物为单气孔型（hypostomatous），仅在叶片下表皮（远轴表皮）分布有气孔。包括模式植物拟南芥（Arabidopsis thaliana）在内的多数草本植物，其叶片上表皮（近轴表皮）同样存在大量气孔。现有气孔发育相关研究多聚焦于远轴表皮气孔，学界对近轴表皮气孔形成机制的认知仍极为匮乏。本研究探究了叶片数目对气孔密度与气孔比例的调控作用，并针对已知远轴表皮气孔发育调控因子缺陷的突变体，分析了其近、远轴表皮的气孔分布模式。研究发现，部分遗传背景下的气孔密度会因不同完全展开叶片而存在显著差异，因此建议在气孔模式分析中采用固定叶位的叶片。本研究结果表明，近轴与远轴表皮的气孔发育至少存在部分独立调控机制，具体证据如下：其一，脱落酸（ABA，Abscisic Acid）生物合成与感知缺陷的植株气孔比例升高；其二，epf1epf2、tmm及sdd1突变体的气孔比例降低；其三，erl2突变体的近轴表皮气孔指数升高，而远轴表皮无此变化；其四，气孔前体细胞优先分布于远轴表皮。针对近轴表皮气孔的后续研究，可为气孔形态与功能的研究提供全新见解。