Melon is one of the most typical vegetables and cash crops to fully meet the ever-increasing demand for fruit products in recent years. Among them, grafting treatment can be used to improve the quality and yield of watermelon. Grafting healing has been one of the key steps to the survival and quality of watermelon seedlings. The graft success can be represented by the reconnection of the vascular bundle between the scion and rootstock. In this study, the fluorescence tracer materials were prepared with nitrogen and sulfur-doped carbon dots (N, S-CDs) with stable fluorescence characteristics and non-toxic performance. Hyperspectral fluorescence imaging was then used to monitor the healing process of watermelon grafted seedlings. Firstly, the N, S-CDs were prepared at 330-630 nm excitation for the outstanding fluorescence emission, as well as the red and blue double emission characteristics. Secondly, the watermelon seedlings 1-8 days after grafting were labeled with the carbon dot staining, and then placed in a dark room, where the labeled images were collected with a high spectrometer. Finally, the hyperspectral map was processed to extract the data. The principal component map was also analyzed for the spectral data. The results showed that there was no connection between scion and rootstock when the N, S-CDs were used for fluorescence tracing. The carbon point substances failed to transfer into the scion through the xylem, leading to no observation at the scion site. By contrast, the scion was connected to the rootstock after the healing of grafted seedlings. The carbon points were then transferred to the scion through the xylem, where the fluorescence was observed at the scion site. The hyperspectral imaging technique can be expected to quickly, automatically and non-destructively identify the healing state of grafted seedlings with the high-throughput phenotypic features under the early healing state of melon crops. The N, S-CDs treatment can also promote the growth of roots and scion leaf area during healing. Within 12 days after grafting, the growth of leaf area and root length of the grafted watermelon seedlings treated with carbon point material were significantly greater than those treated without carbon point material, as the time increased. On the 12th day after grafting, the root growth and leaf area in the treatment group were 78.7% and 61.4% higher than those in the control group, respectively. The absorption of nutrients and water was improved for the photosynthesis of plants, the early transplantation of melon grafted seedlings, whereas, the healing time of melon grafted seedlings was shortened with less manpower, material and financial resources. The finding can provide a strong reference to promote the development of grafted seedlings production and seedling industry.

This study aims to design an advanced lighting system using freeform optical technology. The artificial lighting was also improved in the reproductive efficiency. An artificial lighting system was also developed to dynamically adjust the illuminance in response to the posture of gilts. Thereby, a stable and uniform lighting environment was created to promote the estrus expression for optimal hormonal regulation. The blue and green light were integrated to form a blue-green composite spectrum, in order to closely align with the spectral sensitivity of the pigs. The freeform optics were designed to realize the precise control over the light distribution. There was an average uniformity of 0.87 and a maximum illuminance of 311 lx. The experiment was conducted at the Guangxi Yangxiang Co., Ltd. Guigang Huanglian Pig Farm, China. The gilts were exposed to four lighting conditions: a control group with the conventional white LED lights, a blue light (B), a green light (G), and a blue-green composite light (B&G) group. The blue and green light was also combined in a ratio of 1:1. The lighting system was operated on a 12-hour daily cycle. The levels of the luteinizing hormone (LH) and estradiol (E2) were measured to evaluate their correlation with the estrus expression. The results revealed that the B&G group exhibited the most pronounced estrus behavior, with significantly higher levels of LH and E2 than the rest groups. The elevated hormonal levels were maintained consistently to result in a prolonged and more stable breeding window, which was essential to successful mating. These findings suggest that the combination of the blue and green light effectively stimulated the hormonal process with the estrus induction. In contrast, the green light group shared the less consistent estrus expression and the weaker hormonal responses, indicating that the green light alone was less effective inducing the estrus behavior. Although the blue light group shared the improvement over the control group, there was no same level of consistency or intensity in the hormonal variation as the B&G group. Furthermore, the stability and reliability of the lighting system were also assessed beyond behavioral observations. An ultrasonic distance sensor was incorporated to continuously monitor the posture of the gilts. The illuminance was dynamically adjusted using the distance between the gilt and the light source. The illuminance remained stable, with a ±5% variation whether the gilts were lying down or standing. Moreover, the lighting system also demonstrated impressive energy efficiency, with a 95% energy utilization rate. The energy loss was significantly reduced, compared with the conventional lighting systems. Therefore, freeform optical technology shared the promising potential to customize lighting systems, in order to enhance animal welfare and productivity in modern farming. The B&G lighting system effectively improved the reproductive environment for the gilts, thereby enhancing the reproductive efficiency in the pig industry. Furthermore, artificial lighting was emphasized to regulate animal behavior and physiology, particularly in the context of estrus induction. In conclusion, the freeform optical can be expected to offer a practical and efficient solution to the optimal lighting systems in the gilts, in order to improve both estrus expression and hormonal regulation. The insights were also gained for the valuable guidance of the lighting systems in pig farming or agricultural settings, where controlled lighting influences animal behavior. Future research should focus on refining the parameters of the blue-green light spectrum, such as the optimal light ratio, photoperiod duration, and illuminance, in order to further enhance estrus induction and reproductive performance. These efforts can greatly contribute to more effective, sustainable, and intelligent farming solutions for increasing productivity with animal welfare.