Pressman E, Huberman M, Aloni B, Jaffe M J
Biology Department, Wake Forest University, Winston-Salem, North Carolina 27109, USA.
Plant Cell Physiol. 1984;25(6):891-7.
Mechanical perturbation (MP) applied to celery (Appium graveolens L. cv. Florida 683) leaf petioles or ethephon application to the plant did not induce thigmomorphogenesis (inhibition of elongation and increase in thickness of the petiole). However, the two treatments did cause the parenchyma breakdown which leads to pithiness or increased natural pithiness, mainly at the base of the petiole. Nevertheless, MP (but not ethephon) decreased the severity of drought-stress or GA3-induced pithiness. Although MP stimulates ethylene production, mainly at the middle part of the petiole, it seems that the protection by MP of the petiole may not be directly mediated by ethylene production. The exposure of the plant to drought stress brought about an increase in ethylene evolution. Upon reirrigating the plants, the first steps of pithiness were accompanied by a sharp decline in ethylene production. This decrease might be due to membrane disruption. The increase in ethylene production during drought stress may be one of the events which stimulate pithiness of the celery leaf petiole.
对芹菜（芹菜品种佛罗里达683）叶柄施加机械扰动（MP）或对植株施用乙烯利均未诱导触变形态发生（叶柄伸长受抑制且厚度增加）。然而，这两种处理确实导致了薄壁组织分解，主要在叶柄基部，从而导致髓化或天然髓化加剧。尽管如此，MP（而非乙烯利）降低了干旱胁迫或赤霉素诱导的髓化严重程度。虽然MP主要在叶柄中部刺激乙烯生成，但MP对叶柄的保护作用似乎并非直接由乙烯生成介导。植株暴露于干旱胁迫下会导致乙烯释放增加。对植株重新灌溉时，髓化的最初阶段伴随着乙烯生成的急剧下降。这种下降可能是由于膜破坏所致。干旱胁迫期间乙烯生成的增加可能是刺激芹菜叶柄髓化的事件之一。
