Influence of Rhizosphere Temperature and Humidity Regulation on Rooting, Mortality, and Transplant Survival of Aeroponically Rapid Growth Mulberry Cutting

This study explores the impact of different temperature and humidity conditions on Mulberry cutting rooting and transplanting survival rates in an aeroponically rapid propagation system. It investigates the relationship between droplet adhesion and mortality based on mildew and rot distribution in cuttings. The regulating strategies were divided into three groups: humidity, temperature, and combined humidity and temperature. The humidity group included a fixed spray frequency (H3) and fixed-range humidity conditions (H1: 90% ≤ Humidity ≤ 100% and H2: 95% ≤ Humidity ≤ 100%). The temperature group comprised room temperature (T2) and fixed-range temperature circumstances (T1: 25 °C < Temperature < 27 °C). The non-regulation group (THCK) made no particular modifications, whereas the combined temperature and humidity group (TH) maintained both temperature and humidity within a set range (90% ≤ Humidity ≤ 100% and 25 °C < Temperature < 27 °C). Moreover, the humidity control group (HCK) and the temperature control group (TCK) integrated a soil cultivation system. Then, the transplantation experiment and the droplet adhesion amount experiment were carried out. The results demonstrate that faster callus formation and rooting with aeroponic propagation, temperature and humidity regulation significantly improves root growth and survival rate. The temperature and humidity regulation group outperforms, increased callus rate, rooting rate, average root length, average root number, fresh weight, and dry weight by 30%, 25%, 4.54 mm, 1.09, 0.12 g, and 0.012 g, while reducing mortality by 20%. Conversely, soil culture showed no callus formation or rooting throughout the same timeframe. Significant (p < 0.01) differences between regulation and non-regulation groups exist in growth parameters, mortality, and transplant survival rates. All groups achieved 80–100% transplant survival, with temperature regulation enhancing hardening effects. Excessive droplet adhesion heightens the risk of mortality, with an optimal adhesion threshold of approximately 0.06444 g. This study offers valuable insights into aeroponically rapid propagation and intelligent nurseries.