Comparative Effects of NaCl and Polyethylene Glycol on Seed Germination of Four Native Species for Landscaping under Arid Environment
Comparative Effects of NaCl and Polyethylene Glycol on Seed Germination of Four Native Species for Landscaping under Arid Environment
Hasnain Alam1*, Jabar Zaman Khan Khattak1 and Taoufik Saleh Ksiksi2
ABSTRACT
Due to the increasing scarcity of water, the trend is shifting towards using indigenous species for sustainable landscaping. In this study, we evaluated the germination response under osmotic stresses for four native species i.e. Atriplex leucoclada, Senna italica, Tetraena mandavillei and Tephrosia apollinea. Two osmotic agents (OA) i.e. NaCl and PEG 6000 and four osmotic levels (OL) i.e. 0, -0.2, -0.4 and -0.6 MPa were tested for each species. Data was collected for different germination traits including germination percentage, germinating index, mean daily germination, mean germination time, promptness index, germination stress tolerance index, coefficient of velocity of germination and germination rate. Osmotic stress significantly decreased most of the germination traits, while mean germination time increased with decreasing OL in all four species. A. leucoclada showed significant interactive effect of OA and OL for GP. GP of A. leucoclada was higher in PEG treatment but decreased at -0.6 MPa while NaCl had the lower GP but did not show any decrease with decreasing OL of NaCl. Contrary to this S. italica was adversely affected by PEG as compared to NaCl. Decreasing OL also decreased the GP of S. italica. T. apollinea and T. mandavillei were found to be resistant to both iso-osmotic conditions of PEG and NaCl. However, GP of T. apollinea and T. mandavillei decreased with decreasing OL. T. apollinea and T. mandavillei stood out as the best under both induced salt and drought stress at the germination stages. It is concluded that all four-selected species successfully germinated under maximum osmotic potential understudy which is not suitable for landscape species. All four investigated species can be further evaluated for field performance under stress conditions so can be recommended for mass vegetation and as a substitute to exotic landscaping species.
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