FRUIT GROWTH AND FOOD TRANSPORT IN CUCURBITS

Abstract

Calculations based on Colwell''s 1941 data prove that dry food materials would have to pass through the sieve-tube lumina of Connecticut Field pumpkin peduncles at an av. rate of 16 cm. per hr. to account for fruit growth. For a 7-day period the rate was > 31 cm. per hr. Similar calculations based upon many measurements of fruit growth and phloem areas in 1942 indicate transport rates of 11 and 13.4 cm. per hr. for Connecticut Field pumpkin and Early Prolific Straightneck squash respectively. Such rate values, when converted to linear displacement values for solns., indicate movement at rates of 55-160 cm. per hr. for transport by mass flow. By activated diffusion along the cytoplasm the above rate values indicate diffusion rates of 1000 cm. per hr. or above.