Plant Gene and Trait 2025, Vol.16, No.3, 113-122 http://genbreedpublisher.com/index.php/pgt 117 6 Physiological and Morphological Adaptations 6.1 Vine vigor and canopy microclimate changes High-density planting will significantly affect the growth of grapevines and the structure of their branches and leaves. When planted densely, the total leaf area and the exposed leaf area of each plot will increase, making the entire canopy thicker and denser, and there will also be more water evaporation (Keller and Mills, 2021; Kovaleva et al., 2022). However, the leaves and yield of individual grape plants may decrease. When the canopy structure changes, the microclimate will also be affected. Too dense a canopy will cause poor light and ventilation inside, which will affect fruit development and make the fruits more prone to diseases. Studies have found that the leaf mortality rate within the canopy will increase, which may be related to changes in nutrient distribution and the hot and humid microclimate (Keller and Mills, 2021). However, if the structure of branches and leaves is adjusted reasonably, such as allowing the branches to grow naturally or setting an appropriate rope height, water loss can be reduced, and the photosynthetic efficiency and yield in drought years can also be improved (Kovaleva et al., 2022). 6.2 Photosynthetic efficiency in dense plantings High-density planting, due to the large number of leaves, will increase the overall photosynthetic capacity. However, the photosynthetic capacity of each grape plant itself may be affected (Keller and Mills, 2021). In years when water is relatively abundant, if vertical branches and ropes are set lower, it will help improve photosynthetic efficiency. However, in drought years, freely growing branches and moderate branch and leaf density are more conducive to maintaining photosynthetic activity (Kovaleva et al., 2022). However, if it is too dense, the light cannot enter the interior of the canopy, the photosynthetic efficiency of the leaves will decrease, and the quality of the fruit may also deteriorate, compared with problems such as if the bunches are too tight, there are few fruit grains, and the fruit stems are prone to damage (Tello and Ibáñez, 2018; Keller and Mills, 2021). Therefore, under dense planting conditions, it is very important to manage the structure of branches and leaves reasonably, so as to ensure the effectiveness of photosynthesis and the high quality of fruits. 6.3 Root competition and nutrient uptake Dense planting will also intensify the competition for water and nutrients among grape roots, thereby affecting the morphology and function of the roots. Under dense planting conditions, the number of roots will increase and the number of fine roots will also increase, which is conducive to enhancing the ability to absorb water and nutrients and improving drought resistance (Medrano et al., 2025). However, due to fierce competition, the absorption efficiency of individual grape plants may decline, affecting the growth of the trees and fruit development (Keller and Mills, 2021). In addition, dense planting may also reduce the organic matter and nutrients in the soil, thereby affecting the nutritional status of leaves and the quality of fruits (Ladaniya et al., 2020). Therefore, in high-density planting, how to manage the root system and soil nutrition well is the key to increasing the yield and fruit quality of the vineyard. 7 Economic and Environmental Implications 7.1 Input costs and return on investment The initial cost of high-density planting is relatively high, such as spending a considerable amount of money on seedlings, support frames and irrigation equipment, etc. But in the long run, its payback period is shorter and the risk is relatively lower. For instance, in cherry cultivation, although the high-density approach requires a large investment, due to its stable yield and quick return on investment, the final profit is actually higher than that of the medium and low-density approach (Ghelfi and Palmieri, 2022; Bai et al., 2023). Among crops such as soybeans and corn, if high-density planting is combined with an appropriate reduction in fertilizers, it is possible to reduce costs, increase profits and return on investment while ensuring that the yield does not decline (Han et al., 2020; Bai et al., 2023; Wu et al., 2024). In addition, for some crops with relatively high value, the economic benefits brought by high-density planting are more obvious than those of traditional planting. However, it should also be noted that this method consumes a large amount of resources such as land and water, and may increase environmental pressure (Figure 2) (Su et al., 2023).
RkJQdWJsaXNoZXIy MjQ4ODYzNA==