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Pak. J. Bot., 44: 257-262, Special Issue May 2012. |
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Updated: 06-07-12 | ||||
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KOCHIA SCOPARIA AS A MODEL PLANT TO EXPLORE THE IMPACT OF WATER DEFICIT ON HALOPHYTIC COMMUNITIES
MOHAMMAD KAFI*1 AND MASOUME SALEHI2
Abstract: Most halophyte species experience drought, salinity and high temperature stresses in their growth period, and sensitivity to any of these may affect plant tolerance to others. Among halophytes, Kochia scoparia have recently considered as forage and fodder crop in marginal lands. In order to evaluate interaction of saline water application and water deficit effect on growth parameters, water-salinity production function and physiological parameters, a series of experiments were conducted with different levels of saline water (1.5 to 42 dS/m) and different levels of applied water (25 to 125% of the water requirement) in the farm and greenhouse. Results showed that Kochia like other halophytes is sensitive to drought and salinity at the earliest stages of growth. Salinity reduced linear phase of growth and decreased biomass production but salinity tolerance of Kochia was improved by increasing water application. Evaluation of yield response factor under water deficit and salinity showed that there is not any significant difference among water deficit treatments up to 21 dSm-1. There was no significant difference in biomass of medium drought stress and control. Plants showed more tolerance against drought stress, when stress was induced in the whole growth season. In all experiments, ecotypes from the arid regions, revealed a better response to drought and salinity. Under severe drought and salinity, Kochia still could produce up to 16 and 8 t DM ha-1 biomass in 2009 and 2008, respectively. Salinity tolerance of Kochia was improved by increasing water application. Results of water depletion from different soil layers showed that Kochia uptakes more water from the 30-60 cm soil depth. The soil salinity (ECe) of this section was lower in comparison to the 0-30 cm soil depth. Additionally, the water uptake of the 30-60 cm soil depth improved the salt tolerance level of Kochia. At 75% application of water requirement, Kochia produced 90% of biomass in comparison to 100% water application. Therefore, deficit irrigation is a useful management technique for Kochia even under saline conditions. The results of the present study demonstrated that some indices regarding growth of Kochia and probably other halophytes under salinity, drought and their combination should seriously be revised. Kochia also could be considered as a forage crop or biofuel material by using saline water in semi-arid areas.
1Department of Agronomy, Faculty of Agriculture, Ferdowsi University of Mashhad, Iran. P.O. Box 91775-1163
2Agricultural
and Natural Resources Research Center of Golestan province, Iran. |
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