【摘要】 采用磷酸铅沉淀的细胞化学方法,对番茄子叶细胞内三磷酸腺苷酶(ATPase)活性进行了超微结构的定位,并研究了番茄幼苗在遭受冷害过程中 ATPase 活性的变化。结果指出:1.在28℃下萌发生长的番茄幼苗子叶细胞内的 ATPase 活性被定位于质膜、胞间连丝、核仁及核的染色质、叶绿体片层膜、部分细胞壁以及细胞间隙周围的细胞壁表面及其内含物上。2.当番茄幼苗遭受12小时冷(5℃)处理时,质膜、细胞壁及细胞间隙内的 ATPase 活性开始明显地降低,但细胞核和叶绿体片层膜上的 ATPase 仍保持高的活性反应。在冷处理24小时后,质膜与细胞壁的 ATPase 活性几乎完全丧失,而细胞核和叶绿体片层膜的 ATPase 活性仅开始减弱。这种情况揭示,冷害可能首先损伤细胞表面(质膜与壁)的 ATPase 活性。3.讨论了细胞间隙作为养料运输通道的作用以及冷害的一种可能过程与机理。关于高等植物细胞内三磷酸腺苷酶(ATPase)活性的细胞化学的超微结构定位,以往主要集中于维管束的韧皮部和根尖细胞的研究。不久前,我们报道了冬小麦分蘖节细胞内 ATPase 活性的细胞化学定位叫,初步揭示 ATPase 的活性变化与植物抗寒性有密切关系。番茄等喜温植物在冷害中的细胞超微结构,呼吸作用和一些酶(如过氧化物酶,过氧化氢酶及吲(口朶)乙酸氧化酶)活性的变化,已有一些报道,提出膜可能是冷害损伤的最初部位。然而冷害究竟首先是损伤膜的拟脂成分,还是损伤膜的蛋白质成分,或者是二者同时遭到破坏,目前的实验证据还十分缺乏。ATPase 是膜束缚的一种功能性蛋白质,我们试图通过探索它在寒害中的活性变化,为阐明寒害机理提供实验依据。更多还原

【Abstract】 The ultrastructural localization of adenosine triphosphatase(ATPase)activity in cotyledon cells of tomato was carried out by use of the cytochemical method of lead phosphate precipitation,and the changes in ATPase activity during chilling stress of the tomato seedlings were studied.The following experimental results have been obtained: 1.The ATPase activity in the cotyledon cells of tomato seedlings germinated and grown at 28℃.was located at plasmolemma,plasmodesmata,nucleoli and nuclear chromatin chloroplast lamellae,many sites of cell wall,and the surface of cell wall bordering the intercellular spaces and their inclusions(Fig.1—5). 2.When the tomato seedlings were subjected to chilling treatment for 4 hrs.at 5℃.,the ATPase activity in cotyledon cells(Fig.6)was indifferent from that of non-chilling treated seedlings.After chilling treatment for 12 hrs.at 5℃.,the reaction of ATPase activity at plasmolemma,and in cell wall and intercellular spaces was markedly reduced(Fig.7).though the high activity reaction of ATPase in nuclei and at chloroplast lamellae was still maintained.When the tomato seedlings were subjected to chilling stress for 24 hrs.at 5℃.,the ATPase activity at plasmolemma and in cell wall was almost inactivated,while the ATPase activity in nuclei and at chloroplast lamellae was only slightly lowered(Fig.9—11).These results indicated that the chilling injury may influence firstly on the ATPase activity of cell surface (plasmolemma and cell wall). 3.The role of intercellular spaces used as the passage of materials and the process and mechanism of chilling injury are discussed.更多还原