Effects of Salinity Stress on Growth, Mineral Nutrient Accumulation and Biochemical Parameters of Seedlings of Three Citrus Rootstocks

Abstract

ABSTRACT Citrus is an important fruit crop in Bangladesh and its growth is often constrained by salt stress. A polyhouse experiment was conducted to assess salt tolerance of three citrus rootstocks. Six-month-old seedlings of three citrus rootstocks, namely pomelo, Cleopatra mandarin, and calamansi, were irrigated with six concentrations of NaCl (0.75, 3, 6, 9, 12 and 16 dS m–1) for 3 months. Seedlings of all citrus rootstocks were significantly affected by salinity of irrigation water. All growth parameters were decreased with increase in salinity level of irrigation water. Based on growth parameters, the seedlings of Cleopatra mandarin were the least affected followed by pomelo and calamansi. The seedlings of Cleopatra mandarin accumulated less Na and Cl, while calamansi accumulated the highest amount of Na and Cl. Chlorophyll content was decreased and proline content was increased with increase in salinity level of irrigation water. Proline content was the highest in the leaves of Cleopatra mandarin with 16 dS m–1 salinity level followed by pomelo and calamansi. Overall, Cleopatra mandarin and pomelo rootstocks were more tolerant to saline conditions than calamansi rootstock. The relative susceptibility of citrus species to salinity should be taken into consideration for plant breeding programs, and growing of salt-tolerant citrus rootstocks should be promoted in salt-affected soils for better productivity.