A comparative study of in vitro seed germination ecology in two multipurpose leguminous tree species Albizia lebbeck (L.) Benth and Prosopis cineraria (L.) Druce under experimental saline stress

摘要

Hot and arid zones continuously suffer from high salt accumulation in soil that interferes with normal germination and seed maturation efficacies. Successful seed germination is prerequisite for plant species to thrive well in harsh and hostile environments. Inability of plant communities to colonize these areas is also one of the prime reasons of desertification. Studies have shown that much of the Omani and Arabian land is badly degraded. Here we show the possible solution for reclaiming degraded arid lands of Arabia. We investigated in vitro seed germination efficacies of two common salt tolerant leguminous tree species from Oman along an experimental salt gradient, i.e. 0 mM, 100 mM, 150 mM, 200 mM and 250 mMNaCl. Levin's standardized niche breadth analysis showed that A. lebbeck (L.) Benth had better salt tolerance with broader niche breadth (BA = 0.9075) in all salinity levels (mean germination = 63.347 ± 5.415 % to 33.396 ± 3.575 %). Whereas P. cineraria (L.) Druce was found to be less tolerant with relatively moderate niche breadth (BA = 0.6225) (mean germination = 43.17±6.36 % to 7.30±0.93 %). T-test analysis also confirmed that A. lebbeck performed better than P. cineraria in the present study (mean difference = 20.172 to 35.929 %; t= 2.413 to 7.070; P< 0.05 to 0.001). In earlier studies A. lebbeck has been found to be a significant sequesters species of atmospheric nitrogen. Our results suggest that A. lebbeck from Oman can be used as effective ecological cover to mobilize significant amount of nitrogen in soil and thus reclaiming salt affected degraded arid lands. We recommend that long term field based studies up to seedling, sapling, successful plantation and tree maturation stages should also be performed to collect further data and to quantify the amount of nitrogen sequestration in Arabian soil. Increased use of this suitable nitrogen fixing ecological cover species will eventually enrich pedological conditions of arid ecosystems, initiate autogenic succession and thus help in reclaiming degraded lands of Arabia.