Sodium chloride concentration affects early growth and nutrient accumulation in taro

The growth and nutrient accumulation responses of tare [Colocasia esculenta (L.) Schott, cv. Bun long] to varying sodium chloride concentrations were studied in an aerated hydroponic system. Vegetative propagules were grown a t seven levels of NaCl (0, 5, 10, 20, 40, 60, and 80 mM) for 43 days. We es timated the NaCl tolerance threshold (95% of maximum growth) to be at 4.9 m M solution NaCl. Relative dry-matter yield-decreased 1.6% per mM increase i n solution NaCl above 4.9. These values for tolerance threshold and respons e slope led us to classify this tare cultivar as sensitive to salinity. As solution NaCl levels increased, Na concentration in petiole and root tissue s increased, but mt in lamina (leaf blade) tissues. This implies the existe nce of an effective mechanism for excluding excess Na, in spite of a lack o f tolerance to solution NaCl in terms of growth response. Chloride concentr ation increased in all plant tissues with increasing solution NaCl levels; the greatest increase occurred in petiole tissue, and the lowest in lamina tissue, indicating some ability to partition Cl levels within the plant. Ti ssue concentrations of Ca and Mg, but not of K, were reduced by high soluti on NaCl levels.