Carbohydrate Availability, Respiration, and the Growth of Kenaf (Hibiscus Cannabinus) Under Moderate Salt Stress

Salt stress may impose osmotic and respiratory costs on nonhalophytes that limit the availability of carbohydrates for growth. This was examined in kenaf (Hibiscus cannabinus L.) by the analysis of soluble carbohydrates, starch, and respiration rates in mature and expanding leaves from plants exposed to moderate salt stress. Plants were grown for 35 days in solution culture at 1, 37, and 75 mM NaCl under greenhouse conditions. Total carbohydrates increased in mature and expanding leaves with increasing salinity. The majority of this increase was as starch. Mature leaf respiration also increased under salt stress. The net accumulation of non‐osmotically active carbohydrates in expanding leaves suggests that growth was not limited by the generation or availability of carbohydrates but rather by the ability of the plant to effectively utilize this substrate in osmotic adjustment and growth.