J Syst Evol ›› 2011, Vol. 49 ›› Issue (5): 406-410.DOI: 10.1111/j.1759-6831.2011.00144.x
• Research Articles •
Vijay Kumar Singhal*, Pawan Kumar Rana, Puneet Kumar
Lindelofia longiflora (Royle ex Benth.) Baill. var. falconeri (Cl.) Brand (Family: Boraginaceae) is investigated cytologically (n= 12) for the first time from the cold deserts of Pangi Valley, Chamba District (Himachal Pradesh) in India. We report the formation of syncytes and 2n pollen grains in the species. During meiosis, the majority of the pollen mother cells (PMCs) exhibited 12 bivalents, equal segregation of chromosomes during anaphases, regular tetrads, and normal-sized pollen grain formation. Occasionally, two proximate PMCs fused during the early stages of prophase-I and resulted in the formation of syncytes. The frequency of syncytes in the accession is rather low, at 25 out of 1866 (1.33%). Such syncyte PMCs are detectable during meiosis due to their larger size compared to typical PMCs. The syncytes or polyploid cells showed normal 24 bivalents and depicted perfectly regular meiotic course. But the products of such PMCs yield 2n or larger sized pollen grains that are almost double the size of typical normal or n pollen grains. The origin of syncytes as a consequence of the fusion of meiocytes during the early stages of meiosis-I could be attributed to low temperature stress conditions prevailing in the Pangi Valley, where temperature during May and June dip to below freezing, the time the plants enters the reproductive/flowering bud stage. It is possible that such apparently fertile 2n pollen grains originating from syncytes might play a role in the origin of intraspecific polyploids in the species.
low temperature stress,
Vijay Kumar Singhal, Pawan Kumar Rana, Puneet Kumar. Syncytes during male meiosis resulting in 2n pollen grains formation in Lindelofia longiflora var. falconeri[J]. J Syst Evol, 2011, 49(5): 406-410.
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