Effect of water stress on cations accumulation by maize seedlings (Zea mays L.)

A Laboratory experiment was conducted to evaluate the effect of four different levels of water potential (psi) viz., 0.000, -0.409, -0.818, and -1.228 MPa on the accumulation of K+, Ca2+ and Ne of six cultivar of maize seedlings (Zea mays L.). Mannitol was used as an osmoticum alongwith half strength Hoagland culture solution. Results depicted that in relation to different levels of water stress all mentioned cations responded significantly (P < 0.05). Cultivars response was also found to be significant. Results further depicted that as water stress level increases, all K+, Ca2+ and Na+ contents both in root and shoot are generally decreased. A maximum level of root K+ (2.45 mg g(-1)), Ca2+ (6.42 mg g(-1)) and Na+ contents (108.05 mg kg(-1)) are obtained in control dose of applied water stress (0.00 MPa). While in case of shoot, maximum level of K+ (17.92 mg g(-1)), Ca2+ (4.28 mg g(-1)) and Na+ contents (29.22 mg kg(-1)) are also recorded in stress level of 0.00 MPa. However, except of root Ca2+ and K+, minimum level of cations are found in seedlings receiving water potential of 1.228 MPa. Results based on Drought Tolerance Index (DTI, %) exhibited that a maximum response (25-77%) is recorded for shoot cations as compared with their respective root cations (16-72%). Relatively much higher concentration in shoot than in root suggests that imposed water stress levels did not influence the upward translocation of these ions in general. Results also exhibited that based on cumulative DTI, maize cv. Agaithi-72 could be rated as drought tolerant and cv. Synthetic-551 as drought sensitive. While remaining four cultivars viz., Azam, cv. Composite-15, Yousafwala E.V. 1081 and Ehsan could be rated as drought intermediate in response, respectively.