在盐分胁迫下额外供应钙和钾后，蚕豆叶片的离子稳态和质膜H(+) -ATP酶活性会发生变化。

Leaf ion homeostasis and plasma membrane H(+)-ATPase activity in Vicia faba change after extra calcium and potassium supply under salinity.

作者信息

Morgan Sherif H, Maity Pooja Jha, Geilfus Christoph-Martin, Lindberg Sylvia, Mühling Karl Hermann

机构信息

Department of Ecology, Environment and Plant Sciences, Stockholm University, SE-106 91 Stockholm, Sweden; Institute of Plant Nutrition and Soil Science, Kiel University, Hermann Rodewald Strasse 2, D-24118 Kiel, Germany; Plant Physiology Section, Plant Botany Department, Faculty of Agriculture, Cairo University, 12613 Giza, Egypt.

Department of Ecology, Environment and Plant Sciences, Stockholm University, SE-106 91 Stockholm, Sweden.

出版信息

Plant Physiol Biochem. 2014 Sep;82:244-53. doi: 10.1016/j.plaphy.2014.06.010. Epub 2014 Jun 25.

DOI:10.1016/j.plaphy.2014.06.010

PMID:25010036

Abstract

Salt stress in plants impacts apoplastic ion activities and cytosolic ionic homeostasis. The ameliorating effects exerted by calcium or potassium on compartmentation of ions in leaves under salinity are not fully understood. To clarify how calcium or potassium supply could ameliorate ion homeostasis and ATPase activities under salinity, 5 mM CaSO4 or 10 mM K2SO4 were added with, or without, 100 mM NaCl for 7 d and 21 d to Vicia faba grown in hydroponics. The apoplastic pH was detected with Oregon Green dextran dye in intact second-uppermost leaves by microscopy-based ratio imaging. The cytosolic Ca(2+), Na(+), K(+) activities and pH were detected in protoplasts loaded with the acetoxy methyl-esters of Fura-2, SBFI, PBFI and BCECF, respectively, using epi-fluorescence microscopy. Furthermore, total Ca(2+), Na(+), K(+) concentrations and growth parameters were investigated. The ATPase hydrolyzing activity increased with time, but decreased after long salinity treatment. The activity largely increased in calcium-treated plants, but was depressed in potassium-treated plants after 7 d. The calcium supply increased Vmax, and the ATPase activity increased with salinity in a non-competitive way for 7 d and 21 d. The potassium supply instead decreased activity competitively with Na(+), after 21 d of salinity, with different effects on Km and Vmax. The confirmed higher ATPase activity was related with apoplast acidification, cytosol alkalinization and low cytosolic [Na(+)], and thus, might be an explanation why extra calcium improved shoot and leaf growth.

摘要

植物中的盐胁迫会影响质外体离子活性和细胞质离子稳态。钙或钾对盐胁迫下叶片中离子区隔化的改善作用尚未完全明确。为了阐明钙或钾的供应如何改善盐胁迫下的离子稳态和ATP酶活性，在水培条件下生长的蚕豆中，添加5 mM硫酸钙或10 mM硫酸钾，并分别添加或不添加100 mM氯化钠，处理7天和21天。通过基于显微镜的比率成像，用俄勒冈绿葡聚糖染料检测完整的第二上位叶中的质外体pH。分别使用落射荧光显微镜，检测装载了Fura-2、SBFI、PBFI和BCECF乙酰氧基甲酯的原生质体中的细胞质Ca(2+)、Na(+)、K(+)活性和pH。此外，还研究了总Ca(2+)、Na(+)、K(+)浓度和生长参数。ATP酶水解活性随时间增加，但在长时间盐处理后降低。钙处理的植株中该活性大幅增加，但钾处理的植株在7天后降低。钙供应增加了Vmax，并且在7天和21天内，ATP酶活性以非竞争性方式随盐度增加。相反，在盐处理21天后，钾供应与Na(+)竞争性降低活性，对Km和Vmax有不同影响。已证实较高的ATP酶活性与质外体酸化、细胞质碱化和低细胞质[Na(+)]有关，因此，这可能解释了为什么额外的钙能改善地上部和叶片生长。