Search Results

You are looking at 1 - 6 of 6 items for :

  • Author or Editor: Yuan Zhang x
  • HortScience x
Clear All Modify Search

Air pollution may play a role in gametophytic selection. To estimate whether such selection was occurring, pollen grains from homozygous and heterozygous tomato plants were tested under pollution stress. Homozygous pollen could be expected to respond to pollution more uniformly than heterozygous due to the identical genotype of the pollen grains. Acid rain reduced pollen germination and tube elongation in Lycopersicon hirsutum LA1777 (heterozygous) and Lycopersicon pennellii LA716 (nearly homozygous). UV-B reduced tube length of the pollen from both plants, but ozone only reduced pollen tube length of L. pennellii. The responses of these two kinds of pollen to acid rain, ozone, and UV-B appears to be same in terms of heterozygosity and stress dosages, suggesting the reduction of pollen germination and tube elongation under pollution stress may be mediated through physiological or physical alterations and not a response of different genotypes.

Free access

Camellia oleifera Abel. is one of four major woody oil plants in the world. The objective of the current study was to evaluate the effect of different plant growth regulators (PGRs) and concentrations on direct organogenesis using cotyledonary nodes, hypocotyls, and radicle explants. High induction frequency of adventitious shoots were obtained from cotyledonary nodes, hypocotyls, and radicle explants (85.2%, 73.6%, and 41.0%, respectively) when cultured on half-strength Murashige and Skoog (1/2 MS) medium containing 2.0 mg·L−1 6-benzylaminopurine (BA) and 0.1 mg·L−1 indole-3-acetic acid (IAA). Microshoots from cotyledonary nodes, hypocotyls, and radicle explants were then transferred to 1/2 MS medium containing 2.0 mg·L−1 BA and 0.05 mg·L−1 indole-3-butyric acid (IBA) for shoot multiplication, resulting in 6.9 shoots per explant. The shoots were transferred to Woody Plant Medium (WPM) supplemented with various α-naphthalene acetic acid (NAA) and gibberellic acid (GA3) for shoot elongation. The mean length of shoots and the number of leaves per shoot were 3.7 and 6.6 cm, respectively, in WPM supplemented with 0.5 mg·L−1 NAA and 3.0 mg·L−1 GA3. The highest rooting of shoots (90.2%) or the number of roots per shoot (7.2) was obtained when elongated microshoots were transferred to 1/2 MS medium supplemented with 3.5% perlite, 1.0 mg·L−1 IBA and 2.0 mg·L−1 NAA. The rooted plantlets were successfully acclimatized in the greenhouse with a survival rate of 90.0%. The in vitro plant regeneration procedure described in this study is beneficial for mass propagation and improvement of C. oleifera through genetic engineering.

Free access

Sodium hydrogen sulfate (NaHSO3) in aqueous solution was sprayed on bell pepper (Capsicum annuum) plants beginning at first anthesis to test its effects as a photorespiration represser and resulting effects on yield. NaHSO3 sprays promoted plant height, stem diameter, fruit number and plant weight and increased the net assimilation rate, thus increasing yield. Concentrations of 60, 100, 120, 130, 200, 240 and 300 ppm were all effective, with 200 ppm optimum. Sprays repeated for three times at 7 day intervals were more effective in increasing growth and yield of bell pepper than spraying once or twice. This technique has gained acceptance as a practical method for improving production of bell pepper in Northeast China. Additional research is underway to further refine this practice.

Free access

Hydrogen sulfide (H2S) has been proven to be a multifunctional signaling molecule in plants. In this study, we attempted to explore the effects of H2S on the climacteric fruit tomato during postharvest storage. H2S fumigation for 1 d was found to delay the peel color transition from green to red and decreased fruit firmness induced by ethylene. Further investigation showed that H2S fumigation downregulated the activities and gene expressions of cell wall–degrading enzymes pectin lyase (PL), polygalacturonase (PG), and cellulase. Furthermore, H2S fumigation downregulated the expression of ethylene biosynthesis genes SlACS2 and SlACS3. Ethylene treatment for 1 d was found to induce the expression of SlACO1, SlACO3, and SlACO4 genes, whereas the increase was significantly inhibited by H2S combined with ethylene. Furthermore, H2S decreased the transcript accumulation of ethylene receptor genes SlETR5 and SlETR6 and ethylene transcription factors SlCRF2 and SlERF2. The correlation analysis suggested that the fruit firmness was negatively correlated with ethylene biosynthesis and signaling pathway. The current study showed that exogenous H2S could inhibit the synthesis of endogenous ethylene and regulate ethylene signal transduction, thereby delaying fruit softening and the ripening process of tomato fruit during postharvest storage.

Free access