Transforming organic waste, such as pruning branches into compost and extracting water, can limit the levels of harmful substances in organic waste and decrease the spread of soil-borne diseases, critical for promoting sustainable agriculture. This study employed a pot experiment to examine the influence of water extraction from pruned branches or its compost on root respiration, mitochondrial structure, antioxidant system, and photosynthetic carbon metabolism. The findings demonstrated that the high concentration of pruning branches debris water extract (ST10) exhibited elevated ROS content in the roots and leaves, causing membrane lipid peroxidation, damaging mitochondrial structure, and inhibiting root growth. However, low-concentration pruned branch debris water extract (ST1) did not produce this phenomenon in seedlings. However, pruned branch debris can have its toxicity reduced after composting, and the extracted water can be used as a fast and efficient organic liquid fertilizer. The extracted water (CT1 and CT10) obtained from the composting of pruned branch debris increased the levels of SOD, POD, CAT, and APX and reduced O2 center dot- and H2O2 production in the seedling roots. It also maintained the integrity of the mitochondria. Moreover, the CT1 and CT10 treatments elevated the total root respiration, increased the content of ATP and organic acid in the roots, and promoted root growth. Correspondingly, the CT10 treatment increased the photosynthetic rate and the content of soluble sugars in leaves and roots, offering adequate substrates for respiration, while the ST10 treatment decreased the content of soluble sugars in roots and leaves. These findings indicate that the composting of crushed branches can lower the toxicity of leaching solutions, promote plant growth, and enhance sustainable agricultural development.
Ridging cultivation and root restriction cultivation are beneficial due to their improvement of the soil permeability in the root zone of grapevine, and they are widely used in southern China, Japan, and other countries. However, with the intensification of global warming, when using ridging or root restriction cultivation, the soil temperature in the root zone can often reach 30 degrees C or even more than 35 degrees C during the summer, which is not conducive to the growth of grapevines. The aim of this study was to explore the effects of high root zone temperatures on the photosynthetic fluorescence characteristics of grapevine leaves, root respiration, and degree of lignification of roots and shoots, as well as to provide a theoretical foundation for the management of grapevine production and cultivation. One-year-old potted 'Kyoho' was used as the study material. Three root temperature treatments were implemented for 15 days (9:00-16:00): 25 degrees C (CK), 30 degrees C (T1), and 35 degrees C (T2). The results showed that the malondialdehyde and H2O2 levels in leaves increased, while the chlorophyll content decreased. The oxygen-evolving complex was inactivated, and PSII donor and acceptor sides were blocked, thus reducing the photosynthetic gas exchange capacity at high root zone temperatures. The grapevine root activity and root/shoot ratio decreased. Simultaneously, the lignin content in the roots and shoots increased. In addition, there was a significant increase in the expression of key genes (PAL, C4H, 4CL, F5H, COMT, CCR, and CAD) in the root lignin synthesis pathway. Heightened root zone temperatures increased cyanide-resistant respiration in roots and heat release in the PPP pathway to alleviate stress damage. Therefore, it is recommended to use grass, mulching, and other cultivation management methods to maintain root zone temperatures below 30 degrees C in order to ensure the normal growth of grapevines and promote a high and stable yield.