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Phenolic compounds are important components that affect the taste and health-care function of walnuts. And phenolic compounds in walnut (Juglans sigillata Dode. cv. ‘Qianhe 7’) pellicles at three developmental stages were explored to identify their role. The results showed that the total phenolic content, total flavonoid content, ferric reducing antioxidant power, 2, 2’-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) and 1, 1-diphenyl-2-picrylhydrazyl free radical scavenging activities in pellicles increased gradually during fruits development, and reached the maximum value at maturation period. Syringic acid, gallic acid, catechin, and rutin contents were highly significantly positively correlated with reducing power or highly significantly negatively correlated with IC50 of free radical scavenging activities. Gallic acid and rutin contents were highly significantly positively correlated with phenylalanine ammonia-lyase (PAL) activity. Total phenolic content, syringic acid, catechins, and rutin contents were highly significantly negatively correlated with cinnamate 4-hydroxylase (C4H) and 4-coumarate CoA ligase (4CL) activities. Ferulic acid content was highly significantly positively correlated with polyphenol oxidase (PPO) activity. Overall, PAL, C4H, 4CL and PPO were key enzymes in the metabolism of polyphenols, and they affected the antioxidant capacity of the pellicles by regulating the content of polyphenol during walnut fruit development.

The cadmium tolerance capacity of Canna orchioides was evaluated using glasshouse experiment to lay a theoretical foundation to broad applications of this species in cadmium (Cd) polluted areas. The plant growth, Cd absorption, and antioxidative enzyme activities of canna plants treated with different Cd concentrations (0, 100, and 200 mg · kg−1 per dry soil) for 30 days were investigated. The results indicated that the growth of roots, leaves and stems was restricted following Cd addition. The bio-concentration factor was the highest in the roots, followed by the leaves, rhizomes, and stems. Compared with the control, the translocation factor decreased sharply after 100 mg · kg−1 or 200 mg · kg−1 Cd treatment, whereas the tolerance index decreased significantly under 200 mg · kg−1 Cd exposure. The Cd accumulation rate and total Cd accumulation significantly increased under 200 mg · kg−1 Cd treatment than the control. The malondialdehyde content remained unchanged at different Cd concentrations, while the relative electrical conductivity of the root increased significantly following 200 mg · kg−1 Cd treatment. Cd stress increased significantly the activity of superoxide dismutase (SOD), peroxidase (POD), and ascorbate peroxidase (APX) in the leaves, whereas only SOD was raised in the roots. The catalase (CAT) and POD activity in the roots did not differ significantly at different Cd concentrations. Conversely, APX in the roots decreased significantly under Cd stress, which suggests that the protective mechanisms in the leaves differ from those in the roots. These results indicated that C. orchioides has a high tolerance for Cd. Furthermore, the reactive oxygen species caused by Cd stress could be effectively scavenged by the antioxidative system. The present study proved that C. orchioides constitutes a promising ornamental plant for use in the restoration of areas contaminated with Cd.

The postharvest deterioration of mango fruits is a critical issue limiting mango storage and preservation due to its climacteric nature. This study evaluated the storage behavior of two mango cultivars and their response to exogenous melatonin (MT, 1000 μmol L−1) treatment in attenuating fruit decay and enhancing fruits’ physiological and metabolic processes and gene relative expression subjected to cold storage. MT treatment in both mango cultivars significantly delayed weight loss, firmness, respiration rate, and decay incidence. However, MT did not influence the TSS, TA, and TSS:TA ratio regardless of the cultivar. Moreover, MT inhibited the decrease in total phenol and flavonoid content and AsA content while delaying the increase in the MDA content of mango during storage in both cultivars. In addition, MT dramatically inhibited the enzyme activity of PPO. In contrast, an increase in the activities of antioxidant enzymes (SOD and APX) and PAL and their genes’ relative expression was noticed in MT-treated fruits versus control in both cultivars. However, MT treatment was cultivar dependent in most parameters under study. These results demonstrated that MT treatment could be an essential postharvest treatment in minimizing decay, maintaining fruit quality, and extending mango fruits’ postharvest shelf life by enhancing the physiological and metabolic processes during cold storage.

As the third most edible fungus in the world, Auricularia auricular needs a lot of sawdust for cultivation; thus, it is a win–win method to develop waste wood sawdust suitable for black agaric cultivation. This study evaluated the growth, agronomic characters and nutritional quality of A. auricula cultured on different ratios of miscellaneous sawdust and walnut waste wood sawdust, and comprehensively analyzed the feasibility of cultivating black agaric with walnut sawdust using principal component method (PCA). The results showed that the macro mineral elements and phenolic substances in walnut sawdust were significantly higher than those of miscellaneous sawdust by 18.32–89.00%. The overall activity of extracellular enzymes reached the highest when the ratio of the substrate was 0:4 (miscellaneous sawdust: walnut sawdust). The mycelia of 1:3 substrates grew well and fast. In addition, the growth cycle for A. auricula was significantly lower for 0:4 (116 d) than for 4:0 (126 d). Then, the single bag yield and biological efficiency (BE) were highest at 1:3. Moreover, the nutrients and mineral elements of A. auricula cultivated in walnut sawdust were significantly higher than that of miscellaneous sawdust, expect for total sugar and protein, and the highest overall value was found at 1:3. Finally, the results of comprehensive evaluation by PCA showed that the D value was the highest when the substrate was 1:3 and the lowest when the substrate was 4:0. Therefore, the substrate ratio of 1:3 was the most suitable for the growth of A. auricula. In this study, the high yield and quality of A. auricula were cultivated by waste walnut sawdust, which provided a new way to utilize walnut sawdust.

The boron (B) deficiency tolerance capacity of two grape materials, ‘Xishui-4’ (Vitis flexuosa) and ‘Crystal’ (V. vinifera × V. labrusca), were evaluated using a potted experiment in order to identify the B-use efficiency of grape and screen B-efficient grape resources. The sterile lines of two genotypes of grape were used as test materials, and a large number of test-tube seedlings were obtained through rapid propagation. The test-tube seedlings were acclimatization and transplanted, and the tested seedlings were treated with B stress after survival. In this experiment, the materials were cultured in nutrient solution, which contained 0.00 (B0), 0.25 (B1), and 0.50 (control) mg·L−1 B concentrations, and the two genotypes of grape seedlings were cultured in vitro. The results were counted after 60 days of culture. The results showed that the B deficiency significantly reduced the growth parameters such as plant height, leaf area, total root length, and dry biomass of the two genotypes, and the inhibition of ‘Crystal’ growth parameters was greater than that of ‘Xishui-4’. Moreover, the B deficiency also affected photosynthesis of the two genotypes, such as decreased leaf photosynthetic pigments, net photosynthesis rate, transpiration rate, stomatal conductance, intercellular carbon dioxide concentration, and stomatal density. Interestingly, the decrease ranges of ‘Crystal’ were greater than those of ‘Xishui-4’, indicating that ‘Crystal’ photosynthesis was more susceptible to B deficiency. Under the control condition, the concentration and accumulation of B in ‘Crystal’ were significantly higher than those in ‘Xishui-4’. However, under the condition of B deficiency, the B concentration, accumulation amount, accumulation rate, utilization index, and tolerance index of ‘Xishui-4’ were higher than those of ‘Crystal’, and the B transport capacity of ‘Xishui-4’ was more stable, indicating that ‘Xishui-4’ had a better tolerance against B-deficient stress than ‘Crystal’ did. Therefore, ‘Xishui-4’ is a plant with strong adaptability to B deficiency stress, which can be used as B efficient grape resources and a genetic improvement of B efficient grape.