Embryo development in association with asymbiotic seed germination in vitro of Paphiopedilum armeniacum S. C. Chen et F. Y. Liu.

This paper documents the key anatomical features during the development of P. armeniacum zygotic embryos and their ability to germinate asymbiotically in vitro. This study also examines the effect of media and seed pretreatments on seed germination and subsequent seedling growth. Seeds collected from pods 45 days after pollination (DAP) did not germinate while 95 DAP seeds displayed the highest seed germination percentage (96.2%). Most seedlings (50%) developed to stage 5 from 110 DAP seeds whose compact testa had not yet fully formed. Suspensor cells were vacuolated, which enabled the functional uptake of nutrients. The optimum basal medium for seed germination and subsequent protocorm development was eighth-strength Murashige and Skoog (1/8MS) for 95 DAP seeds and »MS for 110 DAP seeds. Poor germination was displayed by 140 DAP seeds with a compact testa. Pretreatment of dry mature seeds (180 DAP) with 1.0% sodium hypochlorite solution for 90 min or 40 kHz of ultrasound for 8 min improved germination percentage from 0 to 29.2% or to 19.7%, respectively. Plantlets that were at least 5 cm in height were transplanted to a Zhijing stone substrate for orchids, and 85.3% of plantlets survived 180 days after transplanting.

Multiswarm Particle Swarm Optimization with Transfer of the Best Particle.

We propose an improved algorithm, for a multiswarm particle swarm optimization with transfer of the best particle called BMPSO. In the proposed algorithm, we introduce parasitism into the standard particle swarm algorithm (PSO) in order to balance exploration and exploitation, as well as enhancing the capacity for global search to solve nonlinear optimization problems. First, the best particle guides other particles to prevent them from being trapped by local optima. We provide a detailed description of BMPSO. We also present a diversity analysis of the proposed BMPSO, which is explained based on the Sphere function. Finally, we tested the performance of the proposed algorithm with six standard test functions and an engineering problem. Compared with some other algorithms, the results showed that the proposed BMPSO performed better when applied to the test functions and the engineering problem. Furthermore, the proposed BMPSO can be applied to other nonlinear optimization problems.

An improved embryo-rescue protocol for hybrid progeny from seedless Vitis vinifera grapes × wild Chinese Vitis species.

A highly efficient technique of embryo rescue is critical when using stenospermocarpic Vitis vinifera cultivars (female parents) to breed novel, disease-resistant, seedless grape cultivars by hybridizing with wild Chinese Vitis species (male parents) having many disease-resistance alleles. The effects of various factors on the improvement of embryo formation, germination, and plantlet development for seven hybrid combinations were studied. The results indicated that Beichun and Shuangyou were the best male parents. The best sampling time for ovule inoculation differed among the female parents. When hybrid ovules were cultured on a double-phase medium with five different solid medium types, percent embryo formation was highest (11.3-28.3%) on a modified MM3 medium. Percentages of embryo germination (15.4-55.4%) and plantlet development (11.15-44.6%) were all highest when embryos were cultured on Woody Plant Medium + 5.7 µM indole-3-acetic acid + 4.4 µM 6-benzylaminopurine + 1.4 µM gibberellic acid + 2% sucrose + 0.05% casein hydrolysate + 0.3% activated charcoal + 0.7% agar. In the absence of other amino acids, the addition of proline significantly increased embryo formation (36.1%), embryo germination (64.6%), and plantlet development (90.5%). A highly efficient protocol has been developed for hybrid embryo rescue from seedless V. vinifera grapes × wild Chinese Vitis species that results in a significant improvement in breeding efficiency for new disease-resistant seedless grapes.

Cloning and expression analysis of a PISTILLATA homologous gene from pineapple (Ananas comosus L. Merr).

PISTILLATA (PI)-like genes are crucial regulators of flowering in angiosperms. A homologue of PI, designated as AcPI (Genbank accession number HQ717796), was isolated from pineapple cultivar Comte de Paris by reverse transcriptase polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends (RACE). The cDNA sequence of AcPI is 907 bp in length and contains an open reading frame of 594 bp, which encodes a protein of 197 amino acids. The molecular weight was 2.29 kDa and the isoelectric point was 9.28. The alignment showed that AcPI had a high identity with CsPIC2 (78.6%), AoPI (77.4%), OrcPI (75.7%) and HPI2 (72.4%). Quantitative real-time polymerase chain reaction (qRT-PCR) analyses in different tissues showed that the expression pattern of AcPI was different from the B-class genes in eudicots. AcPI was expressed in all the tissues investigated. The expression level was very low in fruit stems, bracts, leaves and sepals, high in petals and carpels, and moderate in apical meristems, flesh and stamens. The qRT-PCR analyses in different stages indicated that the expression of AcPI reached the highest level at 40 days after flower inducement, when the multiple fruit and floral organs were forming. It proved the important role of AcPI in floral organs and fruit development. The 35S::AcPI transgenic Arabidopsis plants flowered earlier and had more inflorescences or branches than wild type plants.

[Mapping of seedlessness gene in grapes using SCAR markers].

Nine primers (including UBC-269 and GSLP1) were designed and synthesized based on DNA sequences of UBC-269(484) and GSLP1(569). The template DNA from Red Globe (seeded paternal parent) and Flame Seedless (seedless maternal parent) were screened using these primers. For Flame Seedless,GSLP1 yielded specific marker GSLP1(569); No. 39970524-5 primer yielded specific marker 39970524-5-564; and No. 6 primer yielded specific marker 39970524-6-1538 and 39970524-6-1200. GSLP1, No. 39970524-5, and No. 39970524-6 primers were used specifically to screen template DNA from the experimental plant materials. The results showed that the specific markers GSLP1(569), 39970524-5-564,39970524-6-1538 and 39970524-6-1200 were cosegregating with the major seedlessness gene. All these specific loci were also present in Thompson Seedless which was the initial donor of the seedlessness gene. It suggests that these SCAR markers are linked to a major grape seedlessness gene S. Markers order and map distance were estimated using the software 'QTXb17'. This showed that GSLP1(569), 39970524-5-564,39970524-6-1538 and 39970524-6-1200 were tightly linked to gene S. When P = 0.01,confidence limits for map distance ranged from 0.2 to 9.9; standard errors of map distance were from 0.6 to 1.9; LOD for linkage were from 32.7 to 46.4. These markers and the gene S were found to be in the same group. The markers were located on either side of gene S, covering 12.3 cM of the grape genome. The genetic distances between gene S and 39970524-5-564, GSLP1(569), 39970524-6-1538 and 39970524-6-1200 were 0.6 cM, 1.2 cM, 4.9 cM and 11.1 cM respectively.