Plasticity of Morphological and Physiological Traits in Caragana korshinskii under Different Habitats of Water Wind Erosion Crisscross Region of the Loess Plateau The D ifferences of Growth and Photosynthetic Tra its of Five Shrubs Spec iesfrom Two Or ig ins in the Northea stern Ulanbuh Desert Selection of Seedling Growth and Photosynthetic Traits Assistant Evaluated Factors in Betula platyphylla Half-sib Families Effects of Four Chemical Regulators on Chilling Tolerance and Photosynthetic Characteristics of Tobacco Seedlings Comparison of Photosynthetic Characteristics in Soybean Cultivars with Different Phosphorus Efficiencies