Open AccessEarly Ovule Development Following Self- and Cross-pollinations in Eucalyptus globulus Labill. ssp. globulus
Author(s) -
Leanne M. Pound,
M. A. B. Wallwork,
Brad M. Potts,
Margaret Sedgley
Publication year - 2002
Publication title -
annals of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.567
H-Index - 176
eISSN - 1095-8290
pISSN - 0305-7364
DOI - 10.1093/aob/mcf089
Subject(s) - ovule , eucalyptus globulus , biology , pollination , endosperm , botany , zygote , horticulture , pollen , embryo , eucalyptus , embryogenesis , microbiology and biotechnology
The study was conducted to identify the self-incompatibility mechanism in Eucalyptus globulus ssp. globulus. Controlled self- and cross-pollinations were conducted on individual flowers from three mature trees that had self-incompatibility levels of 76, 99.6 and 100%. Flowers were harvested at 4, 6 and 8 weeks after pollination. Embryology was investigated by bright field microscopy on material harvested at 4 and 6 weeks after pollination. Fertilization had taken place at 4 weeks after pollination with zygotes and free nuclear endosperm visible. There was a greater proportion of healthy, fertilized ovules in the cross- compared with the self-pollination treatment, and approx. half the ovules examined from both pollen treatments were not fertilized or were degenerating. By 6 weeks after pollination a few zygotes were starting to divide. The number of healthy, fertilized ovules was still greater in the cross-pollination treatment, but the number of healthy fertilized ovules was lower in both treatments compared with 4 weeks after pollination, and many ovules were degenerating. Fertilized ovules were significantly larger than non-fertilized or degenerating ovules and this difference was detectable by eye at 6 and 8 weeks after pollination. The mechanism of self-incompatibility appears to have both late pre- and post-zygotic components.