Growth Response of Orchardgrass (Dactylis glomerata L.) to Different Light and Temperature Environments. I. Leaf Development and Senescence1

Abstract

Orchardgrass, represented by ‘Boone,’ ‘Aberystwyth S‐143,’ and a Portuguese ecotype, was observed through the tenth‐leaf stage in a growth chamber experiment. Plants were started from seed and grown in boxes of soil. Temperatures of 29/21 C (85 F day/72 F night) or 21/13 C (70/55 F) had similar effects on leaf appearance on the main shoot. Leaves appeared more rapidly in the 16,140 than the 10,760‐lux light environment. Boone produced leaves at a faster rate than did S‐143 or Portuguese. Leaf area was influenced by light, temperature, and variety, and interactions of lights ✕ temperatures and varieties ✕ temperatures were observed. Increased leaf area represented mainly increases in length rather than in width of leaf blades. Leaves senesced more rapidly in the 16,140‐ than 10,760‐lux light, 27 and 31 days, respectively. Leaf senescence was not affected by temperature or variety. Boone reached the tenth‐leaf stage sooner, had greater leaf area and was higher yielding than S‐143 or Portuguese. Plants grown in the 21/13 C environment produced more aerial dry matter and had a larger leaf surface than did plants under the 29/31 C regime.