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  • Author or Editor: Jian Li x
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In this study, the effects of different Xinjiang pear varieties and ‘Korla Fragrant Pear’ pollination on the stone cells and lignin of fruit were investigated. The contents of stone cells and lignin, and the activities of related enzymes [polyphenol oxidase (PPO), peroxidase (POD), and phenylalanine ammonium lyase (PAL)] were analyzed in fruit from different pollination combinations at different growth and developmental stages. Results showed that the stone cell mass density decreased rapidly at 60 to 90 days and 90 to 120 days after flowering. The stone cell and lignin contents, and activities of the three enzymes (PPO, POD, and PAL) decreased rapidly at 60 days after flowering. The stone cell mass density, stone cell and lignin contents, and enzyme activity of fruit from different pollination combinations varied at different timescales. The pear variety ‘Bayue‘ had the lowest stone cell and lignin contents in mature fruit from different pollination combinations. The stone cell content correlated positively with lignin content, stone cell mass density, and enzyme activity.

Open Access

Sedum rubrotinctum is widely grown as an ornamental because of its attractive leaf shape and color. Increasing the morphological diversity and color will greatly add to its ornamental value. Environmental conditions such as light and temperature can change the leaf color of succulent plants, but the mechanism is uncertain. To examine this mechanism, we tested the effects of two commercial chemical products Sowing Goodliness (Sg) and Aromatic Garden (Ag) on the morphology, pigment content, and growth performance of Sedum rubrotinctum seedlings. The Sg treatment did not change foliage color, but can accelerate plant growth and increase lateral bud number. The Ag treatment had marked changes on the relative proportions of pigments and leaf color, and plant growth was severely reduced with mortality observed in some plants. After Ag stress was discontinued, the surviving plants began to regrow and had good ornamental value but had the fewest number of lateral buds and leaves, and the smallest leaf length and thickness, canopy diameter, and plant height. Foliage color changes are caused directly by shifts in the relative proportions of pigments, particularly chlorophyll b and anthocyanin. In Ag-treated plants, chlorophyll b declined much faster than chlorophyll a, indicating that the transformation of chlorophyll b into chlorophyll a is an important step in the chlorophyll degradation pathway. Ag provides a way to learn more about the mechanism of chlorophyll degradation and should be investigated further. Ag enhanced anthocyanin production rapidly and improved the ornamental value of Sedum rubrotinctum. Different concentrations of Ag and Sg were not studied in this trial and might be tested to determine the ideal balance between leaf color and plant growth.

Open Access

Sea buckthorn (Hippophae rhamnoides) is an ecologically and economically valuable species that has been widely cultivated as a new berry crop rich in nutritional and medicinal compounds. RNA Sequencing (RNA-Seq) simple sequence repeat (SSR) markers were developed to evaluate the genetic relationships among 91 plants of 31 cultivars from two subspecies, mongolica and sinensis, as well as intraspecific hybrids between them. A total of 7540 RNA-Seq SSRs were identified as potential molecular markers, in which AG/CT (27.57%) was the most abundant unit type. AT/AT (9.93%), and AAG/CTT (11.95%) are the other main repeat motifs. A total of 110 primer pairs were randomly selected for validation of amplification. Seventeen SSR loci, located in genes encoding metabolic processes and cellulose synthases, were identified to be polymorphic among different sea buckthorn cultivars. These SSR loci generated 48 alleles, ranging from 2 to 5 per locus. Cluster analysis based on the proportion of shared alleles and unweighted pair group method with arithmetic average (UPGMA) algorithm divided all the genotypes into two main groups, with all of the ssp. sinensis cultivars (native to China) and hybrids in one group and ssp. mongolica cultivars (introduced from Russia) in the other group, which was in good agreement with their taxonomic classification. The RNA-Seq SSRs developed in this study have a potential use in the conservation of sea buckthorn germplasm and marker-assisted breeding (MAB).

Free access

Large natural genetic diversifications have occurred among Chinese tree peony cultivars under the natural and artificial selections on the flower for ornamental and medicinal uses in the past over 1500 years in China. Paeonia suffruticosa ‘Zi Mei You Chun’ X.Q. Zhao & J.P. Zhao & X.Z. Zhao & X.C. Zhao & Q.X. Gao & Z.Q. Zhao & J.X. Zhao & Z.L. Suo (Paeoniaceae) is a unique cultivar possessing side flowers and bicolored floral disc belonging to the Central Plains tree peony cultivar group of China. This natural mutant is not only an outstanding ornamental, but also a valuable material for scientific research on evolution of tree peony cultivars, metabolic pathways of pigments in the floral disc, origin of floral disc in Paeoniaceae, and other issues in plant evolutionary and developmental genetics.

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Seasonal alteration of the cytosolic and nuclear Ca2+ concentrations of spruce (Picea engelmannii Parry) and brome grass (Bromus inermis Leyss) was investigated by the antimonate precipitation cytochemical technique. Electron microscopic (EM) observations revealed that electron-dense Ca2+ antimonate deposits, an indication of Ca2+ localization, were seen mainly in the vacuole, the cell wall and the intercellular space in samples of both species, collected on 14 July 1997. Few deposits were found in the cytosol and nuclei, showing a low resting level during summer months. On 8 Aug. 1997 following a decrease in daylength of 1 hour and 12 minutes, Ca2+ accumulation was initiated in spruce with increased cytosolic and nuclear Ca2+ deposits, but not in brome grass. On 8 Sept. 1997, Ca2+ accumulation occurred in the cytosol of brome grass. This followed a drop in ambient temperature to 12 °C. Cytosolic and nuclear Ca2+ deposits continued to increase in spruce. Controlled experiments confirmed that it was the low temperature, not shortening daylength, that triggered Ca2+ accumulation in brome grass. High cytosolic and nuclear Ca2+ concentrations lasted about three months in spruce from early August to early November. However, the high cytosolic and nuclear Ca2+ concentrations in brome grass lasted only about 20 days from early September to the end of the month. During winter and spring, both species had low resting cytosolic and nuclear Ca2+ concentrations. The relationship between the duration of the high cytosolic and nuclear Ca2+ concentrations and the status of the developed dormancy/cold hardiness is discussed in light of current findings.

Free access

Cornus florida seeds show strong dormancy. In this study, we investigated the causes of the dormancy by assessing the permeability of the stony endocarp, the germination of seeds after mechanical dissection, and the effect of endogenous inhibitors. Water uptake by intact and cracked seeds during imbibition showed that the endocarp formed a strong barrier for water absorption. Meanwhile, extracts from endocarp decreased the germination frequency of chinese cabbage seeds from 99.3% (control) to 2.7%. Therefore, the endocarp was the mechanical barrier and contained endogenous inhibitors for seed germination. However, the germination percentage of decoated seeds and dissected seeds with the exposed radicle were only 13.3% and 28.7%, respectively. It was found that the endosperm also played a role in seed dormancy. Extracts from endosperm decreased the germination frequency of chinese cabbage seeds from 99.3% (control) to 53.0%. By contrast, extracts from embryo did not affect the germination of chinese cabbage seeds. When tested with the excised embryos, germination percentage was up to 85.3% at the 16th day of incubation. Taking these results together, we concluded that the endocarp and endosperm were responsible for seed dormancy in C. florida. To break the seed dormancy of C. florida, stratification and soaking in sulfuric acid are the effective means. The highest germination frequency was achieved by immersing seeds in 98% sulfuric acid for 10 minutes, then soaking the seeds in 500 mg·L−1 gibberellic acid (GA3) for 72 hours before cold stratification at 5 °C for 60 days.

Free access

Planting date influences grain soybean yield and quality, but no information is available regarding the responses of seed chemical compositions to delayed planting date in vegetable soybean [Glycine max (L.) Merr.]. Three vegetable soybean cultivars, CAS No.1, Tai 292, and 121, were planted on 3 May, 15 May, 27 May, and 8 June in the field during the 2010 and 2011 growing seasons. The experiment was a randomized complete block design with three replications on a typical Mollisol (black soil). We found that late planting reduced fresh pod yield in all cultivars and years. The reduction in fresh pod yield to delayed planting was significantly correlated with the reduction in the number of two-seed pods per plant. Cultivars with strong capacity in retaining more two-seed pods may possess an advantage if planting is delayed. Planting after 15 May increased seed protein content by 4.1% to 7.5% and reduced oil content by 2.4% to 26.3% for different cultivars. The contents of free amino acid, sum of fructose and glucose, raffinose, and stachyose in seed were also increased by late planting. By contrast, late planting reduced the seed sucrose content ranging from 7.6% to 45.5% for the different cultivars. Planting on 3 May usually produced the greatest fresh pod yield and highest seed sucrose content. These results demonstrated that late planting after early May might have a negative impact on the eating quality of vegetable soybean.

Free access

‘Korla’ fragrant pear (Pyrus sinkiangensis T.T. Yu) variety has shown severe coarse skin in recent years. The intrinsic quality of its coarse fruit shows an increase in the number of stone cells and poor taste. In this study, stone cells and the cell wall of coarse pear (CP) and normal pear (NP) during various development stages were compared using paraffin-sectioning and transmission electron microscopy (TEM), and the relationships between lignin-related genes and stone cell formation and cell wall thickening were also analyzed. Our results show that giant stone cells are formed and distributed in the core of pear, whereas many of these crack 60 days after flowering (DAF). The period of stone cell fragmentation occurs later in CP fruits than in NP fruits. Parenchyma cell wall development in CP and NP fruits varies from 120 DAF to maturity. The parenchyma cell wall of CP fruits thickens, whereas that of NP fruits is thinner during the same period. The expression pattern of five genes (Pp4CL1-l, PpHCT-l, Pp4CL2-l, PpPOD4, and PpPOD25) coincides with changes in stone cell content in the pulp. Correlation analysis demonstrates a significant correlation between stone cell content and the expression level of the five genes (ρ < 0.05). In addition, the expression of those five genes and PpCCR1 genes in CP fruits significantly increases during maturation and is highly correlated with the thickness of the parenchyma cell wall. The aim of this work is to provide insights into the mechanism of stone cell and parenchyma cell wall development in pear fruits and identify important candidate genes to regulate the quality of fruit texture using bioengineering methods.

Open Access

The characterization of aroma of the 14 main apricot (Prunus armeniaca L.) cultivars in Xinjiang was evaluated using high-performance solid-phase microextraction (HP-SPME) with gas chromatography-mass spectroscopy (GC-MS). A total of 208 volatiles that include 80 esters, 25 aldehydes, 15 terpenes, 21 ketones, 39 alcohols, 27 olefins, and 1 acid were identified from these cultivars. The compounds propyl acetate, 3-methyl-1-butanol acetate, (Z)-3-hexen-1-ol acetate, d-limonene, β-linalool, hexanal, hexyl acetate, butyl acetate, β-myrcene, ethyl butanoate, and β-cis-ocimene were the major compounds responsible for aroma in these cultivars. GC-MS results showed that Kuchexiaobaixing, Guoxiyuluke, and seven other cultivars were characterized by a high level of esters and were considered to be fruity apricot aroma. ‘Luotuohuang’ and ‘Heiyexing’ accumulate high levels of terpenes and exhibited an outstanding floral aroma. Higher levels of alcohols and aldehydes were observed in ‘Danxing’, ‘Sumaiti’, and ‘Kumaiti’. The latter are considered green aroma cultivars. These three types of cultivars with different aroma characteristics can be significantly differentiated by using the principal component analysis (PCA) method. The contributions of volatiles to the apricot aroma were assessed by using the partial least squares regression (PLSR) model. Esters, terpenes, and C6 components were shown to be responsible for the fruity, floral, and green character of fresh apricots, respectively.

Free access

In this study, simple sequence repeat (SSR) and sequence-related amplified polymorphism (SRAP) markers were used to analyze the genetic diversity of 48 wild Vitis davidii accessions. A total of 78 distinct alleles were amplified by 11 SSR primers, and the average allele number was 8.8. The average observed heterozygosity (Ho) and expected heterozygosity (He) values were 0.785 and 0.814, respectively. The effective allele numbers ranged from 3.92 to 9.61. The average polymorphism information content (PIC) was 0.798. Twelve of 169 SRAP primer combinations were selected for SRAP analysis. A total of 188 bands were produced, and the average was 15.7 bands per primer combination; the average percentage of polymorphic bands was 84.0%. The average PIC was 0.76. The results of the clustering analysis based on SSR markers showed that the 48 wild V. davidii accessions could be classified into five main clusters and had a genetic similarity coefficient level of 0.68. The dendrogram obtained from the SRAP data showed that 48 wild V. davidii accessions could be classified into five main clusters and had a genetic similarity coefficient of 0.72. SSR and SRAP markers differentiated all accessions studied including those with a similar pedigree. We speculated on the origin of Ciputao 0941♀, Ciputao 0940♂, and Fu’an-ci-01 using SSR markers and used both SSR and SRAP markers to resolve homonymy. The result will be valuable for further management and protection of V. davidii germplasm resources.

Free access