为了探究乙烯和α-萘乙酸(α-NAA)是否是水淹环境条件下植物体内通气组织形成的直接原因，对三峡库区岸生植物野古草（Arundinella anomala）和秋华柳（Salix variegata） 在无水淹环境条件下施加乙烯利和α-NAA后茎中通气组织的形成情况进行了研究。实验分3种处理：单独用乙烯利溶液处理（浓度分别为0、250和500 mg●L－1）、单独用α-NAA溶液处理（浓度分别为0、50和100 mg●L－1）和二者混合处理（250 mg●L－1乙烯利溶液 +50 mg●L－1 α-NAA溶液）。处理5 d后，采用切片法制备其茎中部横切面切片，用E80i Nikon显微镜进行观察,并运用ACT-2U和Simple PCI软件分析野古草和秋华柳茎中通气组织的形成情况。结果显示：在这3种处理条件下，野古草和秋华柳茎中通气组织形成均有明显增强，并且较高浓度的乙烯利溶液促使茎通气组织形成更多，施加的α-NAA浓度越高，形成通气组织的能力越强；混合溶液处理与单独施加250 mg●L－1乙烯利或单独施加50 mg●L－1 NAA的处理相比，对通气组织形成的增强效应无明显差异。研究表明，在水淹条件下植物体内通气组织的发生与乙烯和生长素含量的增加有直接关系。
Aims We investigated aerenchyma formation in stems of riparian plants Arundinella anomala and Salix variegataas affected by addition of ethylene and α-naphthalene acetic acid (α-NAA) under non-flooded conditions in order to as certain whether phytohormone ethylene and auxin are direct stimuli for aerenchyma formation in flooded plants.
Methods Our experiment included treatments of ethylene (0, 250, 500 mg●L－1), α-NAA (0, 50, 100 mg●L－1) and joint addition of ethylene andα-NAA (250 mg●L－1 + 50 mg●L－1) for A. anomalaand S. variegata plants. Five days following hormone additions, we obtained transverse sections of mid-stems of A. anomala and S. variegata and analyzed aerenchyma formation using E80i Nikon microscope, ACT-2U and Simple PCI software.
Important findings Aerenchyma formation was enhanced when plants were irrigated with either ethylene orα-NAA. Moreover, aerenchyma formation increased with hormone concentration. Aerenchyma formation was enhanced when plants were irrigated with a mixture of ethylene (250 mg●L－1) andα-NAA (50 mg●L－1), but it did not differ from aerenchyma formation induced by either ethylene addition of 250 mg●L－1 or α-NAA addition of 50 mg●L－1. Our work demonstrates that, in flooded environments, the aerenchyma formation in plant stems is directly related to in creases of ethylene and auxin, and flooding may not be the direct stimulus for the formation of aerenchyma.