Characteristics of Tonoplast Adenosinetriphosphatase and Inorganic Pyrophosphatase in the Chlorenchyma and the Water Storage Parenchyma of Ananas comosus Leaves
CHEN Li-Song 1 NOSE Akihiro 2( 1College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou 350002, P.R.China; 2Faculty of Agriculture, Saga University, Saga 840-8502, Japan)
The characteristics of tonoplast adenosinetriphosphatase(ATPase) and inorganic pyrophosphatase(PPase) in the chlorenchyma and the water storage parenchyma(WSP) of crassulacean acid metabolism(CAM) plant Ananas comosus(pineapple) leaves were investigated. The activities of tonoplast ATPase and PPase in the chlorenchyma were higher than those in the WSP. The optimum temperatures of tonoplast ATPase and PPase activities in the WSP were 43℃ and 49℃, respectively and in the chlorenchyma, 37℃ and 46℃, respectively. The activities of tonoplast ATPase increased with temperature rise when the temperatures were less than their optimum temperatures and decreased when the temperatures were higher than their optimum temperatures. The increase in tonoplast(PPase) ATPase activity in the chlorenchyma was faster than that in the WSP in the temperature ranges of(10-46℃)10-37℃, and the chlorenchyma obviously had(relatively) higher tonoplast(PPase) ATPase activity. The decrease in tonoplast(PPase) ATPase activity in the WSP was less than that in the chlorenchyma in the temperature ranges of(49-61℃) 43-55℃, and the WSP obviously had relatively higher tonoplast(PPase) ATPase activity. In addition, the two enzymes were more thermostable in the WSP than those in the chlorenchyma. The optimum pH and the substrate dependence of the two enzyme activities in both kinds of tissues have also been characterized.