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  • Author or Editor: Fan Li x
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Five peach cultivars [Prunus persica (L.) Batch] with different maturity dates were subjected to sink–source manipulation by girdling to isolate 1-year-old fruit-bearing shoots. Four treatments were performed: fruit were removed (−fruit); one fruit (+1 fruit) and two fruit (+2 fruit) were kept inside two girdling cuts; and two fruit were kept outside two girdling cuts (−fruit*). Photosynthetic responses for the five cultivars were similar and did not show genotypic differences. Generally, net photosynthetic rate (Pn), stomatal conductance (g s), and transpiration rate (E) were higher, and leaf temperature (Tl) was lower in +2 fruit than in +1 fruit, followed by −fruit and −fruit* which were not different. The results also indicated that water outflow from fruit into leaves did not influence photosynthesis, and lower photosynthesis in −fruit treatment was not due to water status of source leaves influenced by removing fruit. Pn tended to increase with Tl until Tl reached a critical level. Beyond the critical temperature level, Pn generally decreased. The critical Tl was roughly identified as 34–37 °C for the five cultivars. Both higher and lower substomatal CO2 (Ci) levels occurred in −fruit and −fruit* treatments than in +1 fruit and +2 fruit treatments, indicating that decreased Pn could be due to both nonstomatal and stomatal limitations. Further analysis of the relationship between Ci and photosynthetically active radiation (PAR) showed that nonstomatal limitation under low sink demand took place mostly under high PAR. Thus, high light intensity, combined with Tl may play an important role in leaf photosynthetic regulation.

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In this study, we present the molecular characterization of 61 Chinese grape landraces and 33 foreign cultivars by using nine microsatellite DNA markers. A total of 115 distinct alleles were amplified, and the average allele number was 12.78. The average observed and expected heterozygosity values were 0.797 and 0.839, respectively. The effective allele numbers ranged from 5.011 to 8.575. The average polymorphism information content (PIC) was 0.816. Eighty distinct genotypes were detected, and new synonyms and homonyms were found. The clustering dendrogram indicated that 94 Vitis materials could be divided into five major groups, and the cluster analysis showed that part of the Chinese grape landraces had a close relationship with the foreign cultivars. Assessment of the true cultivar identity, and the identification of synonyms and homonyms will be a contribution to improve the grape germplasm management and protect breeders’ intellectual rights.

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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.

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Increasing commercial use of controlled release fertilizer (CRF) has prompted the need to predict N release simply and viably in the greenhouse environment. Two CRFs were tested, i.e., P40d and P100d by incubating them for 40 or 100 days either in static water at 10, 15, 20, 25, and 35 °C or in the soil of vegetable plots in a greenhouse lacking temperature controls. Cumulative nitrogen release (CNR) from a CRF was represented by a parabola curve and significantly affected by the incubation temperature. A method to calculate N m (the maximum N release percentage from CRF) was established using a first-order kinetic equation and the method of least squares. N m was 90.9% to 99.9% for P40d and 72.1% to 87.1% for P100d at 10–35 °C, respectively. A relationship function between the N release rate and naturally fluctuating greenhouse soil temperatures was established using the activation energy of the N release reaction. Then a model was constructed with field temperature as the variable to predict N release throughout the entire greenhouse crop production season. The value of ψ representing a property of the coating material of a CRF is 1.0 for the release period of the CRF of 35–55 days and 1.2 of 80–120 days. We validated the model using two seasons of greenhouse tomato, Solanum lycopersicum L., and cucumber, Cucumis sativus L., production data, and found that the error was less than 12% points. This indicated that the constructed model was sufficiently simple, practical, and accurate for use by growers, and fertilizer industry and regulatory personnel.

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The present study aims to reveal the karyotypic characteristics and genetic relationships of apricot (Prunus armeniaca L.) accessions from different ecological groups. Fourteen, 9, and 30 accessions from the Central Asian ecological group, North China ecological group, and Dzhungar-Ili ecological group, respectively, were analyzed according to the conventional pressing plate method. The results showed that all the apricot accessions from the different ecological groups were diploid (2n = 2x = 16). The total haploid length of the chromosome set of the selected accessions ranged from 8.11 to 12.75 μm, which was a small chromosome, and no satellite chromosomes were detected. All accessions had different numbers of median-centromere chromosomes or sub-median-centromere chromosomes. The karyotypes of the selected accessions were classified as 1A or 2A. Principal component analysis revealed that the long-arm/short-arm ratio (0.968) and the karyotype symmetry index (−0.979) were the most valuable parameters, and cluster analysis revealed that the accessions from the Central Asian ecological group and Dzhungar-Ili ecological group clustered together. In terms of karyotypic characteristics, the accessions from the Dzhungar-Ili ecological group and Central Asian ecological group were closely related.

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Ferric chelate reductase (FRO) is a critical enzyme for iron absorption in strategy I plants, reducing Fe3+ to Fe2+. To identify FRO family genes in the local Citrus junos cultivar Ziyang Xiangcheng and to reveal their expression model, the citrus (Citrus sp.) genome was searched for homologies of the published sequence CjFRO1. Five FROs were found, including CjFRO1; these were named CjFRO2, CjFRO3, CjFRO4, and CjFRO5, respectively, and cloned via reverse transcription polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends (RACE) PCR. The deduced amino acid sequences of five CjFROs contained flavin adenine dinucleotide (FAD)-binding motifs, nicotinamide adenine dinucleotide (NAD)-binding motifs, and 6–10 transmembrane domains, with isoelectric points between 6.73 and 9.46, and molecular weights between 67.2 and 79.9 kD. CjFRO1 and CjFRO2 were predominantly found in the aboveground parts of C. junos, with CjFRO1 highly expressed in leaves, and CjFRO2 largely expressed in stems and leaves. CjFRO3 was less expressed in roots, stems, and leaves. CjFRO4 and CjFRO5 were predominately found in roots. Under iron-deficient conditions, CjFRO4 was significantly and specifically increased in the roots of C. junos, whereas CjFRO1 was upregulated in the roots and leaves.

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Wintersweet (Chimonanthus praecox) is a woody garden plant with fragrant flowers, which blooms in deep winter. The vase life of fresh cut flowers is 8–9 days. We applied ethylene and 1-methylcyclopropene (1-MCP; an ethylene action inhibitor) to test the role of ethylene in flower opening and senescence. In addition, abscisic acid (ABA), gibberellic acid (GA3), two cytokinins, 6-benzylaminopurine (6-BA), and zeatin (ZT) were also applied. The expression pattern of CpSRG1, a senescence-related gene, was analyzed. Ethylene treatment accelerated flower opening and senescence, decreasing vase life by 2.1 days. It also decreased flower break strength, indicating the induction of abscission. 1-MCP slowed opening, delayed senescence, and prolonged vase life by 2.6 days. Ethylene dramatically induced the expression of the CpSRG1 gene, while 1-MCP suppressed it. ZT promoted flower opening and increased vase life by 1.6 days. It suppressed the expression of CpSRG1. 6-BA, GA3, or ABA had no significant effect on flower opening and senescence of wintersweet.

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