Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/28172
標題: 結縷草屬植物耐鹽性之研究
Studies on Mechanism of Salt Tolerance of Zoysia spp.
作者: 陳奕君
Chen, Yih-Chun
關鍵字: Zoysia spp.
結縷草屬
salt-tolerance
halophyte
osmatic adjustment
salt gland
leakage
耐鹽性
鹽性植物
滲透調節
鹽腺
滲漏
出版社: 農業經濟學系
摘要: 原生於台灣各地區不同生態環境之結縷草營養系間,其耐鹽能力之差異極大。耐鹽 能力較強之營養系,可在含有7.5% NaCl的水耕液(相當於二倍半海水的鹽度)中三週 尚不致死亡,而耐鹽能力較弱之營養系,則可耐半倍至等倍海水之鹽度,基於此,已可 將之認定為鹽性植物。結縷草生長於高鹽環境下,除了要面臨高濃度鹽分離子之毒害外 ,亦需適應因高濃度之鹽分離子所造成的滲透逆境(缺水效應)。在適應滲透逆境方面 ,結縷草無論在形態或生理上均具有耐旱之特性。在形態上,其葉片上表面的氣孔,皆 被數個球狀構造所包圍,呈凹陷狀,而有些營養系之葉片下表面具有較多的氣孔。在葉 片蠟質分佈方面,其葉片下表面並無蠟質覆蓋,而葉片上表面則均覆有蠟質,且有些營 養系之氣孔亦為之覆蓋,上述構造均可減少水分散失,增加植物耐旱能力。在生理上, 結縷草則會進行滲透調節,於細胞內累積溶質,降低滲透潛勢,以維持細胞膨壓,減輕 滲透逆境之傷害,其累積之溶質,部分是來自外界之鹽分無機離子,如Na+,而部份則是 自行合成之有機溶質,如可溶性糖及脯胺酸等,其中以Na+對滲透調節之貢獻為最大。 在適應離子毒害方面,結縷草可利用位於葉片上表面之鹽腺構造,將進入植體內之鹽分 排出體外,減少蓄積,減輕鹽害,且較耐鹽之結縷草,其葉片上表面具有較多之鹽腺構 造,並有旺盛的泌鹽現象,而較不耐鹽者則反之。此外,在鹽逆境下,較耐鹽之結縷草 ,其膜系較不易受Na+侵害,可維持較正常之選擇通透性,減少細胞發生滲漏。
In Taiwan, Zoysia spp. from different ecotopes significantlly varied in the ability of salt tolerance. The clones of Zoysia spp. with higher salt tolerance could survive in the solution with 7.5% NaCl, about 2.5 times of sea water concentration. Those with lower salt tolerance could also tolerate with the salinity about half to equal concentration of sea water. Thus Zoysia spp. could be defined as halophytes. Under highly saline environment, Zoysia spp. not only challenged to the ionic toxicities, but also adapted to the osmotic stress which was caused by the high concentration of salt ions. Zoysia spp. owned both morphological and physiological characters of draught tolerance for adapting to the osmotic stress. In the view of morphological features, stomata on the adaxial epidermis were surrounded by several ball- shape structures and subsided. In some clones, stomata on abaxial epidermis were more than that on the adaxial epidermis. The abaxial epidermis was not covered with wax, while the adaxial epidermis was covered with wax. The stomata of some clones were covered with wax. These structural characteristics could help reduce water loss and increase drought tolerance. In the view of physio- logical features, Zoysia spp. could accumulate solutes to lower osmotic potential and maintain turgor pressure in the cell through osmotic adjustment to reduce the damages. The accumulated solutes consisted of the out-coming inorganic ion such as Na+, and the synthesized products such as soluble sugar and proline. Among the total solutes, the Na+ played the most important role to osmotic adjustment among the solutes. For adapting ionic toxicities, Zoysia spp. could extrude salt by the salt glands which were located on the adaxial epidermis to reduce the salt accumulation and damages. The clones of Zoysia spp. with higher salt tolerance had much more salt glands on the adaxial epidermis and were more active in salt-excreting than those with lower salt tolerance. Further, the membrane system of Zoysia spp. with higher salt tolerance was more stable to maintain the regular selective permeability to prevent the cell from leaking under high concentration of Na+ accumulated.
URI: http://hdl.handle.net/11455/28172
Appears in Collections:應用經濟學系

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