Chilling injury in okra (Hibiscus esculentus L.) and the relationship of chilling to nitrogen, amino acids, proteins and nucleic acids

The effect of low temperature at two relative humidities on the development of okra plants and changes in total and soluble nitrogen, free amino acids and proteins were studied. The levels of RNA and the rates of RNA and protein synthesis after chilling were also determined. Okra (Hibiscus esculentus L.) variety green velvet, at two growth stages were subjected to three temperature regimes and two levels of relative humidity for 144 hours in controlled growth rooms, and returned to the greenhouse after treatments. The treated plants were graded for the severity of injury. All plants treated at 5° were injured and the young plants died after 6 days. Injury to the older plants included a terminal "die back" which became more apparent with subsequent growth. Regrowth originated from the lower part of the stems. At 10°, less damage was observed in plants at both stages than was evident at 5°. Chilled plants showed a decline in the number of flowers when compared to plants treated at 25°. ..