‘Akizuki’ (Pyrus pyrifolia Nakai) is a dominant Asian pear cultivar with gradually increasing cultivation area in Shandong province. However, this cultivar is found susceptible to cork spot disorder in recent years. In this study, we explored the physiological-biochemical mechanism of cork spot disorder in pear fruit, and investigated the effectiveness of spraying calcium (Ca), boron (B) solution or prohexadione calcium (P-Ca) on cork spot incidence. Cork spotted fruit had the characteristics of significantly larger fruit size with shorter fruit pedicels. Compared with normal fruit, cork spotted fruit had lower content of total soluble solids, soluble and reducing sugar, and vitamin C. In addition, cork spotted fruit accumulated much higher levels of N and Mg, and lower levels of K and P. However, Ca deficiency was not observed in cork spotted fruit, on the contrary, we determined high concentrations of Ca and free Ca2+ in disordered fruit. At the same time, the ratios of K/Ca, Mg/Ca, and (K+Mg)/Ca were significantly lower in cork spotted fruit as compared with normal fruit. Among all treatments, spraying with 3500 times dilution of P-Ca at 15-day intervals from 30 to 90 days after full bloom showed promise for reducing cork spot incidence in ‘Akizuki’ pear without affecting fruit quality attributes. This research herein reveals the physiological-biochemical characteristic of cork spot disorder, and implicates P-Ca as a potential tool to reduce cork spot incidence in Asian pear cultivar Akizuki.
Paeonia ostii T. Hong & J. X. Zhang is a perennial oil and medicinal plant with great importance as well as landscaping. P. ostii is being extensively planted in China, but the soil fertility limits the yield and quality. There is little information available on the effects of phosphorus fertilization on productivity, physiological characteristics, and seed yield and quality. This study investigated the influence of different phosphorus levels, 0 kg·hm−2 (CK), 90 c−2 (P1), 135 kg·hm−2 (P2), 180 kg·hm−2 (P3), 225 kg·hm−2 (P4), and 270 kg·hm−2 (P5), on the photosynthesis, morphology, physiological parameters, and yield of P. ostii. The results indicated that the net photosynthetic rate, stomatal conductance (gS), and transpiration rate of P. ostii increased significantly with the application of P4, which increased by 34.77%, 65.72%, and 21.00% compared with CK, respectively. Simultaneously, the contents of soluble sugar, soluble protein, and photosynthetic pigment in P4 were the highest compared with other treatments. In addition, thousand-grain weight (326.4 g) and seed yield per plant (37.33 g) of P4 were significantly higher than the control. However, the total amount of unsaturated fatty acids in P4 was lower compared with other treatments. The indexes of high correlation coefficients with Dim 1 and Dim 2 were gS and superoxide dismutase (SOD), respectively. The results showed that phosphorus levels improved plant photosynthetic capacity and increased antioxidant capacity as well as seed yield. Furthermore, phosphate fertilizer had significant effects on the oil composition. Moreover, the effect of phosphorus application rate on the growth index of P. ostii was greater than that of the physiological index.
Fruit textural characteristics can affect the storage, transportation, and processing of plum (Prunus salicina Lindl) in commercial production. We analyzed 23 plum cultivars with marked differences in fruit traits. Basic physicochemical indicators and textural characteristics of the fruits were determined using puncture testing and texture profile analysis. Furthermore, through the combined application of cluster analysis and principal component analysis, the indexes were simplified to three relatively independent dimensions, comprehensively reflecting the hardness, size, and flexibility of plum fruit. Our results show a high positive correlation among textural characteristics such as hardness, springiness, gumminess, and chewiness, whereas toughness and brittleness were negatively correlated. In addition, physicochemical properties were correlated to the texture traits. The weight and size of the plum fruit were related to hardness, adhesiveness, and chewiness. The soluble solids and water content contributed to the hardness, cohesiveness, and resistance to chewing. Cluster analysis revealed three distinct clusters: Cluster I represented by ‘Meiguihong’ with high hardness and a chewable texture; Cluster II represented by ‘Siyuecui’, ‘Cuimi’, and ‘Qingcui’ with a hard and brittle texture; and Cluster III represented by ‘Jinmi’, ‘Taoli’, and ‘Oishiwase’ with a soft and tough texture. The results of this study provide a significant theoretical foundation for quality evaluation, and classification of plum fruit characteristics, thus providing insights for further breeding of plum varieties.