高光谱荧光示踪无损检测瓜类作物嫁接苗愈合状态

为了减少瓜类嫁接苗的愈合管理时间,实现快速准确判别嫁接苗早期愈合状态,促进嫁接苗规模化生产及育苗产业发展。该研究制备了氮硫掺杂碳点,以该碳点为荧光示踪材料,以西瓜嫁接苗为研究对象,利用高光谱荧光成像方法,探究了西瓜嫁接苗早期愈合状态无损检测的高光谱荧光示踪成像方法。高光谱荧光示踪图像及光谱分析结果表明,利用氮硫掺杂碳点进行荧光示踪,通过高光谱成像仪对瓜类作物早期愈合状态高通量表型的鉴定,能快速、自动、无损地获取嫁接苗愈合的情况。同时,通过氮硫掺杂碳点处理后第12天,处理组的西瓜嫁接苗相较于对照组,根系增长量提升了78.7%,叶面积增长量提升了61.4%。因此,该研究方法可以提早判别嫁接苗的愈合连通,促使瓜类嫁接苗提早移栽,并且氮硫掺杂碳点处理可以促进嫁接苗叶面积和根系的生长,达到种苗壮苗的作用。

Nondestructive detection of healing state of grafted seedlings of melon crops by hyperspectral fluorescence tracer

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 12 th 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.