International Journal of Horticulture, 2024, Vol.14, No.6, 355-367 http://hortherbpublisher.com/index.php/ijh 361 Figure 2 The schematic diagram of ridge-furrow rainfall harvesting system (Adopted from Feng et al., 2020) Image caption: The ridge-furrow rainfall harvesting system uses transparent polyethylene film to cover the ridges, reducing soil water evaporation and promoting crop growth by retaining soil moisture and regulating temperature. In the experiment, this technique significantly improved soil moisture retention, positively impacting water use efficiency and yield of rapeseed, providing stable water support for rapeseed cultivation during both drought and rainy seasons (Adapted from Feng et al., 2020) 6 Growth Regulators and Hormone Management 6.1 Application of growth regulators in rapeseed production The application of growth regulators in rapeseed production has shown significant potential in enhancing yield and quality. For instance, wood vinegar, a byproduct of biochar production, has been found to act similarly to plant growth regulators. Zhu et al. (2021) found that applying 400-fold diluted wood vinegar during the seedling and overwintering stages significantly enhanced rapeseed seed yield, leaf area index, and silique number per plant by 9.58%, 23.45%, and 23.80%, respectively. When wood vinegar was combined with gibberellins, sodium gluconate, and melatonin, yields increased further, while the incidence of diseases such as Sclerotinia sclerotiorumand Peronospora parasitica was reduced, thereby improving rapeseed quality. Another study showed that foliar spraying with salicylic acid and putrescine alleviated the effects of water stress on rapeseed production. This treatment enhanced antioxidant enzyme activity, increased leaf water content, membrane stability, and chlorophyll content, leading to significant increases in seed and oil yield, demonstrating the effectiveness of plant growth regulators in improving plant stress tolerance (Ghassemi-Golezani et al., 2019). Additionally, exogenous strigolactones (SLs) promoted lateral root growth by reducing endogenous auxin levels, thus enhancing overall plant growth and seed yield (Ma et al., 2020). 6.2 Influence of hormone balance on rapeseed flowering and pod formation Hormone balance plays a crucial role in the flowering and pod formation of rapeseed. Auxin, a key plant hormone, has been shown to regulate the timing of the transition from vegetative to reproductive growth. A study on the effects of different nitrogen levels on floral primordium differentiation in rapeseed found that high nitrogen treatment advanced the timing of floral primordium differentiation by 4 to 7 days and increased yield by approximately 11.1% to 22.6% (Hao et al., 2022). During this process, auxin synthesis primarily occurred through the significant accumulation of indole-3-acetonitrile. The study also demonstrated that the expression of genes related to auxin synthesis and signaling pathways varied across five differentiation stages under different nitrogen levels, further indicating that high nitrogen levels accelerated floral primordium differentiation by modulating the auxin pathway. The balance of other hormones such as gibberellins and strigolactones also influences flowering time and pod formation. For example, gibberellins have been implicated in promoting floral initiation under low-temperature conditions, particularly in semi-winter rapeseed varieties (Luo et al., 2022). Moreover, the interaction between 14-3-3 proteins and vernalization-related flowering regulators further underscores the importance of hormone balance in flowering regulation (Fan et al., 2022).
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