Intra-fruit seed abortion in a wind dispersed tree, Dalbergia sissoo Roxb: proximate mechanisms

Mohan Raju, B. ; Uma Shaanker, R. ; Ganeshaiah, K. N. (1996) Intra-fruit seed abortion in a wind dispersed tree, Dalbergia sissoo Roxb: proximate mechanisms Sexual Plant Reproduction, 9 (5). pp. 273-278. ISSN 0934-0882

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Official URL: http://www.springerlink.com/content/364w582p12721w...

Related URL: http://dx.doi.org/10.1007/BF02152702

Abstract

Dalbergia sissoo, a tropical tree with wind-dispersed pods, exhibits a highly positively skewed distribution of seeds per pod with predominantly only one of the four or five ovules maturing into seed. The abortion cannot be attributed to lack of pollen or resources. This study examines the hypothesis that the abortion is due to an intense rivalry among the developing sibs to gain dispersal advantage. Aqueous extract of the dominant embryos at the stigmatic end that generally develop to maturity significantly inhibited the uptake of labelled sucrose by the young developing (subject) embryos in an in vitro assay system. Extracts of tissues such as subordinate (peduncular embryos), unfertilized ovules and pod coat did not cause such inhibition. Aqueous diffusate of dominant embryos also inhibited the uptake of labelled sucrose by subject embryos. The chemical substance responsible for the inhibition appears to be heat-stable and non-proteinaceous. HPLC analysis indicated the presence of two retention time peaks, different from that of standard indole acetic acid, but with considerable overlap. We hypothesize that the compound could be an indole derivative. We propose that the stigmatic embryos have a head start due to earlier fertilization and produce a chemical that either directly (by metabolically killing) or indirectly (by preventing the uptake of assimilates) kills the proximally placed peduncular embryos.

Item Type:Article
Source:Copyright of this article belongs to Springer-Verlag.
Keywords:Dalbergia sissoo; Seed Abortion; Sibling Rivalry; Diffusate; 14C Sucrose Uptake
ID Code:13208
Deposited On:11 Nov 2010 06:35
Last Modified:31 May 2011 11:33

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