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Pak. J. Bot., 42(4): 2813-2825, 2010. |
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Updated: 09-12-10 |
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EFFECT OF SEED MASS VARIATIONS ON THE GERMINATION AND SURVIVAL OF THREE DESERT ANNUALS
SEEMI AZIZ AND SYED SHAHID SHAUKAT
Abstract: This study is focused on the germination and survival of three desert annual viz., as Ipomoea sindica Stapf., Cleome viscosa L., and Digera muricata Forsk., influenced by the variations in the seed size. The frequency distribution of seed size of each species was constructed and the seeds were sorted out in three over-lapping size classes categorized as small, medium and large. Seed size variations were higher for I. sindica, having higher values of coefficient of variation (25.11 %), followed by C. viscosa (17.24 %) and D. muricata (13.09 %). Large, medium and small-size seeds of three selected species were allowed to germinate. Higher germination rates were observed in large-size seeds followed by medium and small-size seeds. Clear-cut effect of seed size was also observed on growth and survival of plants. Plants emerged from large-size seeds of three species were more likely to survive to maturity. It was due to the fact that large-size seeds have large food reserves, which help them to cope with adverse conditions.
Department of Botany, University of Karachi, Pakistan, Karachi-75270. |
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