Responses of seeds of Azadirachta indica (neem) to short-term storage under ambient or chilled conditions
1995
Berjak, P. (University of Natal, Durban (South Africa). Department of Biology, Plant Cell Biology Research Unit) | Campbell, G.K. | Farrant, J.M. | Omondi-Oloo, W. | Pammenter, N.W.
Neem seeds show curious post-shedding behaviour and have been variously documented as orthodox, intermediate or recalcitrant, apparently relating to provenance. In addition, even in the air-dry state, hermetically stored seeds rapidly lose viability. In the present case, putatively recalcitrant, hydrated neem seeds from a Kenyan coastal provenance were stored in loosely-closed polythene bags to ascertain: 1. Whether or not the axes showed metabolic enhancement indicative of the onset of germination under ambient storage conditions for 10 days; and 2. Whether chilling had an adverse effect on the axis cells. There was a slight germination lag relative to the control material in the ambient-stored seeds, which is ascribed to their partial enclosure, but the totality of germination was unaffected, while chilling had markedly adverse effects on both rate and totality. The ultrastructure of control material, sampled prior to storage, was typical of embryonic axes in the stage of late development or early stages of germination. During ambient storage, there was considerable enhancement of ultrastructural features indicating that germination (even though slightly delayed) was indeed underway. In contrast, a regression of subcellular development accompanied chilling, many axis cells showing degenerative changes. In terms of this behaviour, seeds of A. indica from this African provenance conform to the characteristics expected of tropical recalcitrant species
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