Paeonia ostii is a woody oil crop with potential value as an edible oil. With the aim of acquiring systematic knowledge of the development of P. ostii seeds, the oil content, biomass, and water content of the seeds were determined. Changes in the distribution of hydrogen protons in P. ostii seeds during follicle development were traced using magnetic resonance imaging (MRI). The formation of oil bodies in the endosperm and embryo was observed using transmission electron microscopy (TEM). Dynamic changes in oleic acid, linoleic acid, and α-linolenic acid contents were assessed by gas chromatography-mass spectrometry (GC-MS). The magnetic resonance images showed that, during early follicle development [45–85 days after flowering (DAF)], a greater quantity of liquid mucus was present within the seeds, and seeds in the same follicle developed at different rates. At 95 to 115 DAF, proton density was distributed evenly in all areas of the seed. A small dark area appeared in the center of the seed, and mucus in the follicles and water in the pericarp disappeared gradually. TEM observations showed that at 45 DAF, a few oil bodies were scattered at the cell periphery in the endosperm, and oil bodies were more numerous in the embryo. With the progression of seed development, the number and size of oil bodies in the embryo and endosperm continued to increase. The fresh and dry mass of P. ostii seeds increased from 45 to 105 DAF, then decreased after 105 DAF. The moisture content decreased, whereas the oil content increased and attained 33.1% at seed maturity. The three predominant unsaturated fatty acids accumulated simultaneously and showed stages of initial accumulation (45–65 DAF) and rapid accumulation (65–105 DAF). The results suggest that 65 to 105 DAF is a critical period for unsaturated fatty acid accumulation in P. ostii seeds.
Yuting Zou, Yanan Wang, Mingwei Zhu, Shuxian Li and Qiuyue Ma
Yong Zhang, Chunxia Fu, Yujing Yan, Xiaodan Fan, Yan’an Wang and Ming Li
Application of sugar alcohol zinc (SA-Zn) spray to apple trees at certain developmental stages can improve fruit quality. Increasing the Zn concentration of fruit can improve nutritional content and promote human health. We conducted foliar application of SA-Zn to 13-year-old ‘Fuji’ apple trees at different developmental stages. The effects of SA-Zn application on Zn concentration, reducing sugar content, and carbohydrate metabolism-related enzyme activity in fruit were investigated. The foliar treatment increased Zn and reducing sugar concentrations significantly in mature fruit. Sorbitol dehydrogenase activity was higher in the fruit of trees treated before budbreak and 3 weeks after flowering compared with the control at the early fruit stage and was higher during fruit expansion in plants treated after termination of spring shoot growth. Mature fruit of trees treated during the fruit expansion stage showed higher sorbitol dehydrogenase activity than the control. Foliar SA-Zn treatment did not have a significant effect on sorbitol oxidase activity in apple fruit. Treatment before budbreak and at 3 weeks after flowering led to a significant increase in the activity of sucrose synthase and acid invertase at the early fruit stage. Treatment during the fruit expansion stage significantly increased the activity of acid invertase at maturity but had no effect on the activity of neutral invertase. Our results indicate that foliar SA-Zn application resulted in biofortification of Zn in apples, which led to higher activity of carbohydrate metabolism-related enzymes and accumulation of sugars.
Zong-zhe Wan, Ya-nan Li, Xin-yu Qi, Dan Wang and Ling Wang
Jie Zhang, Hong-yan Liu, Xin-yu Qi, Ya-nan Li and Ling Wang
Yong Zhang, Chunxia Fu, Yujing Yan, Yan’an Wang, Ming Li, Meixiang Chen, Jianping Qian, Xinting Yang and Shuhan Cheng
This research was initiated to determine the response of apple (Malus ×domestica) fruit quality to sprays of zinc sulfate (ZnSO4) and sugar alcohol zinc. Two apple cultivars Fuji and Gala were evaluated, the leaf zinc (Zn) concentration of which were about 14.3 mg·kg−1 dry weight without Zn deficiency symptoms. The trees were sprayed with ZnSO4 and sugar alcohol zinc separately during four different developmental stages: 2 weeks before budbreak (P1), 3 weeks after bloom (P2), the termination of spring shoot growth (P3), and 4 weeks before harvest (P4). The fruit was harvested at maturity and analyzed for fruit quality and fruit Zn concentration. Zinc sprays during the four different developmental stages increased Zn concentration of peeled and washed fruit at harvest, without phytotoxicity. The treatments at stages P2 and P4 increased average fruit weight of ‘Gala’ and ‘Fuji’, respectively. The treatments at stages P1 and P4 increased the fruit firmness of ‘Gala’, while the treatments at stages P1 and P2 increased the fruit firmness of ‘Fuji’. The treatments at stages P1, P2, and P4 increased the soluble sugar and vitamin C of ‘Gala’ fruit, while the treatments at all the stages increased the soluble sugar and vitamin C of ‘Fuji’. And the effects of sugar alcohol zinc were equal and more pronounced than those of ZnSO4. Thus, Zn sprays at critical periods can improve fruit quality of apple trees, which show no Zn deficiency symptoms with leaf Zn concentration less than 15 mg·kg−1 dry weight.