Cloning and Expression Analysis of Heat-Shock-Protein LsHsp70-3701 Gene From Leaf Lettuce Under High Temperature Stress Effects of NH4+-N/ NO3--N ratios on kinetics of nitrate uptake by two typical lettuce genotypes in hydroponics Comprehensive Evaluation Analysis on Cultivation Effects of Lettuce under Different Nitrogen Levels In Vitro Shoot Differentiation from Cotyledon Explants of Lettuce Cloning and Expression Analysis of LsHsp70 from Lactuca sativa   Studies on the Chemical Constituents of the Essential Oil in the Semen of Lactuca setiva L. and Its Diuretic Action Cloning and Expression Analysis of LsHsp70 from Lactuca sativa   Effect of Nitrogen Forms on the Growth and Physiological Characteristics of Lactuca sativa L.Seedlings In Vitro Shoot Differentiation from Cotyledon Explants of Lettuce EFFECTS OF SODIUM SULFATE AND SODIUM BICARBONATE ON THE GROWTH OF LETTUCE