7Wardlaw I F.The control of carbon partitioning in plants.New Phytologyst,1990,116:341-381.
8Jones J B.Soil testing and plant analysis:Guides to the fertilization of horticultural crops.Horticulture Review,1985,7:1-68.
9Sugar D,Righetti T L,Sanchez E E,Khemira H.Management of nitrogen and calcium in pear trees for enhancement of fruit resistance to post harvest decay.Horticulture Technology,1992,2(3):382-387.
10Marschner H.Mineral Nutrition of Higher Plants.Academic Press,1990.
