Growth and Abscission in Sea Island Cotton. 
BY 
T. G. MASON, M.A., 
Economic Botanist and Acting Assistant for Cotton Research , The Imperial Department op 
Agriculture , West Indies. 
With fourteen Figures in the Text. 
Introduction. 
T HE immediate object of the studies reported in the present paper was 
to obtain information concerning both the external and the internal 
factors responsible for the premature shedding of the flower-buds and the 
young fruit (bolls) of the cotton-plant in St. Vincent. The economic 
importance of premature abscission is not, of course, confined to the 
cotton-plant, for it is responsible for considerable losses in a large number 
of cultivated plants. Future investigation may reveal how far the con- 
clusions arrived at in the course of the present work are of wider appli- 
cation. 
Before reporting the results, reference should be made to the con- 
clusions of previous investigators of the problem. The work of Balls (1) in 
Egypt established a strong presumption that the major factor initiating 
abscission was a marked water-deficit in the body of the plant. It was 
found that the elongation of the stem of the cotton-plant was checked 
immediately the sun struck upon it, and that a slight shrinkage usually 
followed. A cloud passing across the sun, for instance, was effective in 
permitting growth, which ceased again as soon as the sun emerged. Balls’s 
conclusion that a net loss of water was the direct cause of growth-inhibition 
and boll-shedding received confirmation from Lloyd’s (6) studies, which 
were conducted under the relatively humid conditions of Alabama. 
Ewing’s (2) work in Mississippi also indicated that a disturbance in the 
water-balance of the plant was the main factor responsible for shedding. 
In St. Vincent, where cotton is probably cultivated under more humid 
conditions than elsewhere, Harland (3) noted that shedding was heaviest 
after torrential rain. His observations led him to conclude that root 
absorption was interfered with as a result of the reduction in the oxygen- 
[ Annals of Botany, Vol. XXXVI. No. CXLIV. October, 1922.] 
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