Embryo rescue technology plays an important role in seedless grape breeding.  However, the efficiency of embryo rescue, including the embryo formation, germination, and seedling rates, is closely related to the parental genotypes, degree of abortion, growth medium, and plant growth regulators.  In this study, we investigated the effects of different concentrations of paclobutrazol (PAC), a plant growth regulator, and embryo collection times on the embryo formation, germination, and seedling rates for different hybrid combinations of grape breeding varieties used for their aroma and cold-resistance traits.  The results showed that the different PAC concentrations had varying impacts on the development of ovules and embryos from the different grape varieties.  The embryo formation rates of the ‘Sultanina Rose’בBeibinghong’ and ‘Kunxiang Seedless’בTaishan-2’ crosses were the highest under the 5.1 μmol L^–1 PAC treatment.  The 1.0 μmol L^–1 PAC treatment was optimal for the germination and seedling development of the ‘Sultanina Rose’בBeibinghong’ embryos, whereas the 0.2 μmol L^–1 PAC treatment induced the highest germination rate for the ‘Sultanina Rose’בKunxiang Seedless’ cross.  The optimal sampling times for each cross varied as 39 d after pollination (DAP) for the ‘Flame Seedless’בMuscat Hamburg’ cross, 46 DAP for the ‘Kunxiang Seedless’בBeibinghong’ cross, and 41 DAP for the ‘Ruby Seedless’בBeibinghong’ and ‘Fantasy Seedless’בShuangyou’ crosses.  Moreover, the medium modified with 0.5 g L^–1 of indole-3-butyric acid allowed the malformed seedlings to develop into plantlets and achieve larger progenies.  This study provides a useful basis for further studies into grape embryo rescue and could improve breeding efforts for new seedless grape varieties.

    The small heat shock protein (sHSP) chaperones are required for protecting cellular proteins from damage, as well as refolding denatured proteins. This study was carried out to investigate the temporal-spatial expression patterns of two sHSP genes in rice. These two genes, named as Os16.9A and Os16.9B, are reverse duplicated genes that adjacently located on chromosome 1 and probably share the same or overlapping DNA region as a promoter. The interval sequence between the start codons of the two genes which are transcribed in opposite directions is only about 2.6 kb. Semi-quantitative RT-PCR was carried out to detect the expression of the two genes under normal growth conditions and different stress conditions. The expression patterns of the two genes were in detail investigated by using β-glucuronidase (GUS) reporter gene fusion system. Results showed that heat shock stress can induce high level expression of the two genes. Under normal growth conditions, Os16.9A and Os16.9B expressed in vegetative organs and young panicles. GUS staining combined with cytological observations showed that the two genes expressed mainly in the vascular tissues of roots, stems and young panicles, implicating that Os16.9A and Os16.9B play important roles not only for heat shock response, but also for normal development in rice.