Hayatsu Manabu, Suzuki Suechika, Hasegawa Ai, Tsuchiya Shinpei, Sasamoto Hamako
Department of Biological Sciences, Faculty of Science, Kanagawa University, Hiratsuka, Kanagawa 259-1293, Japan; Research Institute for Integrated Science, Kanagawa University, Hiratsuka, Kanagawa 259-1293, Japan.
Department of Biological Sciences, Faculty of Science, Kanagawa University, Hiratsuka, Kanagawa 259-1293, Japan; Research Institute for Integrated Science, Kanagawa University, Hiratsuka, Kanagawa 259-1293, Japan.
J Plant Physiol. 2014 Sep 15;171(15):1385-91. doi: 10.1016/j.jplph.2014.06.008. Epub 2014 Jul 1.
The effect of a high concentration of NaCl on the intra- (cytoplasmic matrix and vacuole) and extracellular (cell wall) distribution of Na, Cl, K, Mg, Ca, S, and P was investigated in suspension-cultured cells of the mangrove halophyte Sonneratia alba and compared to cultured cells of glycophytic rice (Oryza sativa). No significant differences were observed in ultrastructural features of cluster cells of both species cultured with and without 50mM NaCl. Quantitative X-ray microanalysis of cryosections of the cells cultured in the presence of 50mM NaCl showed that the Na concentration ([Na]) and Cl concentration ([Cl]) significantly increased in all three cell components measured. In S. alba, the [Na] was highest in the vacuole and lowest in the cytoplasmic matrix, while the [Cl] was highest in the cell wall and lowest in the cytoplasmic matrix. In O. sativa, however, the [Na] and [Cl] were highest in the cell wall, and the [Na] was lowest in the cytoplasmic matrix. Thus, the possible activities for Na and Cl transport from the cytoplasmic matrix into the vacuole were greater in S. alba than in O. sativa, suggesting that halophilic mangrove cells gain salt tolerance by transporting Na and Cl into their vacuoles. In O. sativa, the addition of NaCl to the culture medium caused no significant changes to the intracellular concentrations of various elements, such as K, P, S, Ca, and Mg, which suggests the absence of a direct relationship with the transport Na and Cl. In contrast, a marked decrease in the Ca concentration ([Ca]) in the cytoplasmic matrix and vacuole and an approximately two-fold increase in the P concentration ([P]) in the cytoplasmic matrix were found in S. alba, suggesting that the decrease in the [Ca] is related to the halophilic nature of S. alba (as indicated by the inward movement of Na(+) and Cl(-)). The possible roles of a Na(+)/Ca(2+) exchange mechanism in halophilism and the effect of the [P] on the metabolic activity under saline conditions are discussed.
研究了高浓度氯化钠对红树林盐生植物海桑悬浮培养细胞内（细胞质基质和液泡）和细胞外（细胞壁）中钠、氯、钾、镁、钙、硫和磷分布的影响，并与甜土植物水稻（Oryza sativa）的培养细胞进行了比较。在添加和不添加50mM氯化钠的情况下培养的两种植物的簇状细胞的超微结构特征未观察到显著差异。对在50mM氯化钠存在下培养的细胞的冷冻切片进行定量X射线微分析表明，在所测量的所有三种细胞成分中，钠浓度（[Na]）和氯浓度（[Cl]）均显著增加。在海桑中，[Na]在液泡中最高，在细胞质基质中最低，而[Cl]在细胞壁中最高，在细胞质基质中最低。然而，在水稻中，[Na]和[Cl]在细胞壁中最高，[Na]在细胞质基质中最低。因此，海桑中钠和氯从细胞质基质转运到液泡中的可能活性比水稻中更大，这表明嗜盐红树林细胞通过将钠和氯转运到液泡中来获得耐盐性。在水稻中，向培养基中添加氯化钠对细胞内各种元素（如钾、磷、硫、钙和镁）的浓度没有显著影响，这表明与钠和氯的转运没有直接关系。相比之下，在海桑中发现细胞质基质和液泡中的钙浓度（[Ca]）显著降低，而细胞质基质中的磷浓度（[P]）增加了约两倍，这表明[Ca]的降低与海桑的嗜盐性质有关（如由Na(+)和Cl(-)的向内移动所表明）。讨论了Na(+)/Ca(2+)交换机制在嗜盐性中的可能作用以及[P]对盐胁迫条件下代谢活性的影响。
