Crop Response to Trickle Irrigation / DC Elfving -- Tipburn of Lettuce / Graham F Collier, Theodore W Tibbitts -- Photoperiodism / Frank B Salisbury -- Flowering / Ralph Scorza -- Alternate Bearing in Fruit Trees / SP Monselise, EE Goldschmidt -- Flower Bud Induction in Apple Trees: Internal Control and Differentiation / T Buban, M Faust -- Nitrogen Metabolism, Translocation, and Recycling in Apple Trees / John S Titus, Seong-Mo Kang -- Beneficial Aspects of Physiological Stress / William Grierson, James Soule, Kazuhide Kawada