Development of an optimal light environment control system for low light irradiation-low temperature storage of transplants

针对移植物低光照射-低温贮藏最佳光环境控制系统的开发和实际应用，提出了以下两个问题：(1)建立了维持移植物CO_2交换速率为零的光合光子通量密度（PPFD）自动控制系统，从而抑制移植物在长期贮藏期间干重的变化；(2)研究了红蓝发光二极管(led)-LLI贮藏期间蓝光光子通量密度对嫁接番茄插拔苗质量的影响。首先使用gtps进行了一系列系统运行测试，然后在运行测试的基础上，通过对硬件配置和PID参数的改进和修改，完成了存储系统。其次，在整个存储过程中，在恒定的PPFD条件下，使用GTPSs进行存储实验，并将蓝光PPFD在视觉质量评分中的百分比增加到50%，观察到改善趋势。结果表明，50%的蓝光PPFD是最佳的，将蓝光PPFD增加到50%有助于提高gtps LLI储存的质量。最后，将GTPSs在10℃下，在4种不同的LLI条件下保存35 d：固定红光照射2 μmol m^<-2> s^<-1>， pid控制红光照射无蓝光，pid控制红光照射0.2或1.0 μmol m^<-2> s^<-1>。结果表明，在LED-LLI过程中，PPFD的自动控制如预期的那样抑制了干重的变化。此外，研究发现，添加低百分比的蓝光改善了gtps的形态外观，降低了抑制干重变化所需的PPFD。

The following two matters were addressed towards the development and practical application of an optimal light environment control system for low light irradiation (LLI)-low temperature storage of transplants : (1)development of an automatic control system of photosynthetic photon flux density (PPFD) for maintaining the CO_2 exchange rate of transplants at zero, resulting in suppressing the change in dry weight of transplants during long-term storage, and (2)investigation of the effect on the quality of grafted tomato plug seedlings (GTPSs) of blue-light PPFD percentage during red and blue light-emitting diodes (LEDs)-LLI storage. A series of system operating tests with GTPSs were firstly carried out, and the storage system was then completed through improvements and modifications of the hardware configuration and PID parameters based on the operating tests. Secondly, storage experiments with GTPSs were carried out under a constant PPFD condition throughout the storage, and an improving tendency was observed by increasing the percentage up to 50% of blue-light PPFD in visual quality scores. The results indicated that the 50% of blue-light PPFD was the best percentage among the tested ones and increasing the percentage up to 50% contributed to quality improvements for LLI storage of GTPSs. Finally, GTPSs were stored with the completed storage system at 10℃ for 35 d under four different LLI conditions : fixed red light irradiation at 2 μmol m^<-2> s^<-1>, PID-controlled red light irradiation with no blue light, and PID-controlled red light irradiation with blue light at 0.2 or 1.0 μmol m^<-2> s^<-1>. The results showed that the automatic PPFD control during LED-LLI helped suppress changes in dry weight during storage as expected. Furthermore, it was found that addition of a low percentage of blue light improved the morphological appearance of the GTPSs and reduced the PPFD required to suppress the change in dry weight.