关键词: 农业景观, 农业生态系统镶嵌, 景观生态学

Abstract: A water culture experiment was conducted to study the changes of Na⁺,K⁺, Ca²⁺, Mg²⁺, and Cl^- contents in different organs of maize seedlings under NaCl stress. With increasing concentration of NaCl in the medium, the Na⁺ and Cl^- contents and Na⁺/K⁺ and Na⁺/Ca²⁺ ratios in different organs of maize seedlings increased rapidly, and the change extent of the Na⁺, K⁺, and Cl^- contents was in the order of root > mature sheath > young blade > mature blade, suggesting that maize seedling’s root was most easily affected by environment ion concentration, while blade was less affected. Under NaCl stress, the Ca²⁺ and Mg²⁺ contents in seedling’s root decreased while those in mature blade increased, but the Mg²⁺ content in mature blade sheath had no obvious change. The seedlings had Na⁺-exclusion mechanism, presenting definite salt-tolerance. The Na⁺ was mainly accumulated in root and mature blade sheath, and less transported to mature and young blades. The mature blade sheath also had Cl^- exclusion capability.

Key words: Agricultural landscape, Agroecosystem mosaics, Landscape ecology