Melatonin maintains the storage quality of fresh-cut Chinese water chestnuts by regulating phenolic and reactive oxygen species metabolism

Fresh-cut Chinese water chestnuts (CWCs) are prone to quality deterioration during storage, which does not meet consumer demand. In this study, the effect of exogenous melatonin (5 mM) on the quality and potential mechanisms in fresh-cut CWC was investigated. The results showed that melatonin treatment alleviated the cut-surface discoloration of CWCs. Not only did this treatment significantly slow down the increase in browning degree and b* as well as the decrease in L*, but also significantly delayed the loss of weight and total soluble solids. Further investigations indicated that melatonin-treated fresh-cut CWCs exhibited significantly lower total phenolics and soluble quinones and suppressed the activities of phenylalanine ammonia-lyase, polyphenol oxidase, and peroxidase. Meanwhile, when fresh-cut CWCs were treated with melatonin, the total flavonoid concentration was significantly decreased compared to the control. Additionally, melatonin significantly inhibited the accumulation of H2O2 and malondialdehyde (MDA) as well as enhanced the activities of superoxide dismutase and catalase by promoting the production of O2 -·. In summary, melatonin treatment may delay the surface discoloration of fresh-cut CWCs by inhibiting phenolic compound metabolism and improving antioxidant capacity, thereby effectively maintaining the quality, and prolonging the shelf life of fresh-cut CWCs.

Sustainable Countermeasures for the Development of Ecological Compensation in the Watershed

As the state and society pays more attention to watershed environment and water ecological environment in recent years, watershed ecological compensation has increasingly become an indispensable part of promoting watershed environmental development and protecting the ecological environment of watersheds. It is not optimistic to look at the current situation of Chinese water ecological environment. In order to practice the concept of green development and protect the environment of the water resources, it is urgent to study the ecological compensation system of the water resources. Here, the connotation and significance of ecological compensation in the river basin are pointed out, and the sustainable suggestions and countermeasures for the development of ecological compensation in the water resources are accordingly put forward.

Critical geopolitics, the Shanghai cooperation organization and the sino-kazakh water agreements

The Shanghai Cooperation Organization (SCO), previously known as the Shanghai Five, was formed in June 2001 as a security engagement organization. It is a highly influential organization in the Eurasian continent, and most Central Asian countries – Kazakhstan included - are members of SCO, as well as China. In recent years, the Chinese water diplomacy towards Kazakhstan has advanced in different agreements that are shaping the patterns of water security in Central Asia. The Chinese strategic interest in the development of the scope of the SCO in this region has made Kazakh transboundary water issues to advance in negotiations. However, these agreements have been made in a bilateral scheme, which is considered relatively unequal towards Kazakh interests; therefore, in spite of the Kazakh efforts, the SCO so far has not turned into a water security organization. This paper is going to analyze the current trends in the Shanghai Cooperation Organization, as well as the Sino-Kazakh cooperation platform, especially regarding transboundary water resources. From the perspective of the critical geopolitics scholarship and its considerations regarding the concepts of hegemony and zones of influence, the idea that the Sino-Kazakh cooperation has advanced following Chinese interests is going to be defended. In conclusion, this paper states that due to the lack of interest regarding Chinese water diplomacy, and despite of Kazakh efforts, the SCO is not in the near future launching great initiatives regarding water security in the region, reinforcing the Chinese diplomacy of bilateral water agreements. Recebido em 14/04/2021Aprovado em 19/09/2021

UJI ATRAKTAN PADA EKSTRAK PURUN TIKUS (Eleocharis dulcis) SEBAGAI PERANGKAP HAMA PENGGEREK BATANG PADI PUTIH

Purun tikus (Eleocharis dulcis) are wild plants found on swamp land which are quite abundant in South Kalimantan. This research was conducted to find out the most active extract from Chinese water chestnut as an attractant of white rice stem borer (Scirpophaga innotata). Purun tikus were made into extracts using the stepwise extraction method using n-hexane, ethyl acetate, and methanol, with yields of 0.74%, 0.81%, and 7.58%, respectively. The results of the attractant test on purun tikus extract showed that the extract of n-hexane purun tikus was the most active extract as an attractant in white rice stem borer (Scirpophaga innotata). The results of the analysis using GC-MS showed that the extract of n-hexane purun tikus contained several compounds, namely 2-methyltetrahydrofuran, isopulegol, citronellal, citronellyl acetate, βcitronellol, Z-citral, 1-bromo-3,7-dimethyl-2,6-octadiene, citral, linalyl acetate, trans-caryophyllen, trans-phytol, verticellol.

Effect of Planting Time on Growth and Corm Yield of Chinese Water Chestnut (Eleocharis dulcis) in the Mekong Delta, Vietnam

Experiments were conducted to study the effect of time of planting on the performance of Chinese water chestnut in the Mekong Delta in Vietnam over a single investigation. Plants of a local clone were planted in early January, March, May, July, September, or November and grown for four months. During the experiments, the photoperiod ranged from 11.2 to 12.6 h. The average daily mean temperature across the different cropping periods ranged from 27.70C to 29.10C. Information was collected on chlorophyll fluorescence, plant growth, and yield. Chlorophyll fluorescence (Fv/Fm) was greater than 0.7 in all the treatments (non-stressed), except for the first time of planting and at the end of growing. Corm yield was higher with a planting in May (525 g/plant), November (440 g/plant), and March (325 g/plant), intermediate with a planting in July (196 g/plant), and lower with a planting in January (116 g/plant) and September (55 g/plant). There were strong correlations between yield and the number of stems/plant (r = 0.84), and between yield and stem weight (r = 0.84). These results indicate that acceptable commercial yields can be achieved with water chestnut planted in May in this area.