Cucurbit Genetics Cooperative Report 10:7 (article 6) 1987
Chlorosis Induced in Glabrous Cucumber by High Temperature
R. W. Robinson
Horticultural Sciences Dept., New York State Agricultural Experiment Station,
Geneva, NY 14456
Glabrous (gl) cucumber plants are sensitive to heat stress. When
grown in the field at Geneva, NY gl plants often grow well early
in the season but, as temperatures increase in midsummer, their growth is
reduced and their leaves develop a mottling that is not due to a virus.
Glabrous plants grown in a greenhouse at 70°(day)-60°F
(night) had good growth and development as long as they remained at that
temperature regime. When some of the gl plants were moved to a growth
chamber at constant 95°F, however, leaves developing subsequently
were yellow. The nature of the chlorosis was not determined, but the symptoms
were similar to those induced by iron deficiency. Plants dominant for gl did not develop chlorosis of young leaves in the growth chamber.
Glabrous plants returned to the 60-70° greenhouse, after one week
in the 95°F growth chamber, resumed normal growth and development.
Their newly developed leaves were the same color as those of glplants
not exposed to heat stress.
The plants for these tests were grown in Hoagland's nutrient solution,
facilitating examination of their root systems. The glplants differed
markedly from + plants by having fewer lateral roots and root hairs, suggesting
that gl may restrict ion uptake under stress conditions.