Red carbon dots (R-CDs), yellow-green carbon dots (Y-CDs) and blue carbon dots (B-CDs) were successfully synthesized by one-step hydrothermal method using o-phenylenediamine and dopamine hydrochloride as raw materials by adjusting the pH of the reaction solvent. The Fourier transform infrared (FT-IR) spectra, X-ray photoelectron spectroscopy (XPS) spectra and optical properties of CDs show that these three CDs have similar types but different contents of functional groups, resulting in different fluorescence emission. R-CDs and Y-CDs compound with polyvinyl alcohol (PVA) to form bright R-CDs/PVA and Y-CDs/PVA phosphors, while B-CDs/PVA phosphors have weak fluorescence. Compared with R-CDs and Y-CDs solution, the fluorescence emission of the phosphors was significantly enhanced for the matrix inhibits the process of non-radiative transition. Based on the thermostability and broad emission peaks of CD-based phosphors, light-emitting diode (LED) was fabricated using R-CDs/PVA and Y-CDs/PVA phosphors as fluorescent material. The prepared LED exhibits white light with a color coordinate of (0.32, 0.33), correlated color temperature (CCT) of 6067 K and color rendering index (CRI) of 78.2. The environmental-friendly CD-based white light-emitting diode (WLED) was successfully fabricated.

The regulation of plant growth and developmental processes by carbon dots (CDs) has been frequently reported. However, little is known about how CDs are related to the yield and nutritional quality. In this study, carbon dots, obtained by the hydrothermal method with l-cysteine and glucose, were systematically characterized and applied to lettuces and tomatoes in a hydroponic nutrient solution to comprehensively investigate the mechanism of regulation of plant development by CDs. We found that CDs could accelerate seed germination, promote root and hypocotyl elongation of seedlings by activating the expression of genes encoding aquaporin proteins, and enhance the yield and nutritional qualities of mature plants by promoting the absorption of mineral elements together with the enhancement of photosynthesis. These results provide systematic insights into the mechanisms by which CDs regulate plant development.

Carbon dots (CDs) profiting from their stable photoluminescence, small size and good biocompatibility have been used in higher organic fields. The relationship between CDs and edible fungi was less reported. Herein, blue emission CDs are prepared by one-step hydrothermal synthesis, and applied on oyster mushroom (Pleurotus ostreatus) for studying the relationship between CDs and mushroom. Laser scanning confocal imaging shows that the CDs could enter into mushroom hypha. The CDs also can transport among the sporophore. The CDs could be nutrition for oyster mushroom hypha growth in PDA-free medium, and the enhancement effect of CDs on edible fungi hypha is dose-response. Using high concentration on sporophore, their growth would not be affected. It shows that the sporophore of oyster mushroom has well toxicity tolerance for CDs. This study illustrates the relationship of uptake, translocation and toxicity of CDs on edible fungi, which lays the foundation for CDs further application on edible fungi system.

白光LED器件作为新一代绿色固态照明光源,已广泛应用于照明、液晶背光等领域,也与智能照明、物联网技术等高新科技产业密切相关。常用的蓝光芯片复合黄光YAG∶Ce 3+ (Y 3 Al 5 O 12 ∶Ce 3+ )荧光粉的白光器件由于缺少红色光谱的成分,导致器件光谱较窄,显色指数较低,色温偏高。因此,红色荧光粉对改善白光LED的光色品质起到了重要作用。本文首先制备了红色碳点（量子效率28%）,通过把红色碳点与纤维素复合,制备了红色荧光粉（量子效率为18%）。该红色荧光粉与黄光YAG∶Ce 3+ 荧光粉混合,封装得到暖白光。结果表明,相较于只有黄光YAG∶Ce 3+ 荧光粉封装的LED,红色荧光粉掺杂之后,在460 nm蓝光芯片的激发下,白光LED的色坐标由（0.30,0.33）变化到（0.33,0.35）,色温从7 396 K下降到5 714 K,显色指数从78.2升高到82.9,实现了由色温高、显示指数低的冷白光向色温低、显色指数高的暖白光的调节。

In this paper, the fracture surfaces of a light-conversion film were observed using a scanning electron microscope (SEM), and then, the fluorescence spectra and mechanical properties of the film were tested. The SEM results show that the average diameter of the light conversion agent is 500 nm. The results of the mechanical properties tests show that the tensile strengths of light-conversion film increase from 9.86 to 12.16 MPa and that the strain at breakage increases from 2.37% to 2.75%. In addition, the application effects of the light-conversion film were studied. The results indicate that plant height, length of the maximum leaf, width of the maximum leaf and breadth of the plants increase by 24.43%, 15.30%, 15.60% and 19.07%, respectively. The quality of Chinese flowering cabbages treated with the light-conversion film is superior, including a 9.09% increase in the soluble protein content, a 21.27% increase in the polyphenol content, and a 19.15% increase in the soluble sugar content. Based on these results, light-conversion films can be applied in agricultural production. (C) 2020 Chinese Society of Rare Earths. Published by Elsevier B.V. All rights reserved.

The eggplant (Solanum melongena L.) is rich in vitamin P (also known as rutin), which is beneficial for humans. In this study, the vitamin P contents of 53 eggplant lines were measured via UV spectrophotometry. The results showed that the vitamin P content differed significantly among the eggplant lines and the actual contents of vitamin P in fresh fruit pulp and fresh peel were 0.18–0.82 mg · g−1 and 0.42–2.32 mg · g−1, respectively. Furthermore, the mixed major gene and polygene inheritance model method was used for the inheritance analysis of the vitamin P content in F2 populations of three hybridization combinations. Inheritance analysis demonstrated that the vitamin P content of these eggplant lines was a quantitative trait. One or two major genes were the contributor, and the genetic effect was an additive-dominance effect. The high vitamin P content trait was regulated by the main gene and followed an additive effect. The heritability of the major genes controlling the high vitamin P content was low, while the heritability of the major gene that controls the low vitamin P content trait was high. These results provide a theoretical basis for the breeding of eggplants with high vitamin P content.

采用水热法制备了荧光硅量子点.通过透射电镜、红外光谱、X射线光电子能谱、光致激发和发射光谱及荧光衰减曲线等手段对样品形貌及发光性能进行了研究.通过生菜种植实验,研究了荧光硅量子点作为叶面光肥提高生菜对光能利用效率的效应.实验结果表明,透射电镜测得所制备的荧光硅量子点尺寸均一,平均尺寸为3.6 nm.傅里叶红外变换光谱及X射线光电子能谱表明该量子点表面具有丰富的含氧官能团,因而具有优异分水散性.光致荧光光谱表明,该量子点的最佳激发和发射峰位分别为385 nm和450 nm,且不具备激发波长依赖特性.荧光硅量子点与生菜的离体叶绿体复合后发现,荧光强度下降但激发态寿命基本不变,同时,复合物对2,6-二氯酚靛酚的还原速率提高.以上结果表明,荧光硅量子点与叶绿体复合时产生了内滤效应,生菜的叶绿体吸收了硅量子点发射的蓝光用于光合作用,从而使生菜的干鲜重均得到了显著性提高.通过叶绿素荧光成像实验进一步验证了喷施荧光硅量子点叶面光肥时生菜的光合作用速率得到了提高.

An “off−on” assay system for H2O2 determination was developed based on assembling ultra-bright fluorescent silicon quantum dots (SiQDs) and PEG-MnO2 nanosheets. Among them, SiQDs acted as fluorometric reporter, which can effectively eliminate the interference of plant pigments under excitation of 365 nm. PEG-MnO2 nanosheets played dual function of nanoquencher and H2O2 recognizer. Unlike previous reports, the quenching mechanism of SiQDs by PEG-MnO2 nanosheets is attributed to both the associative effect of inner filter effect and the static quenching effect. Thus, the fluorescence intensity of SiQDs at 445 nm decreased with increasing concentration of PEG-MnO2 nanosheets. After addition of H2O2, PEG-MnO2 nanosheets were reduced to Mn2+, consequently resulting in the recovery of the SiQDs fluorescence. Combined with these properties, an off-on fluorescent method was built for determination of H2O2 in plant leaves with high sensitivity and selectivity. The present method has two linear ranges: from 0.05 to 1 μM with a detection limit of 0.09 μM and from 1 to 80 μM with a detection limit of 4.04 μM.

A silicon oxide quantum dots (Si-O QDs) and Ag nanoclusters hybrid nanosensing probe with dual-emission and small nanocrystals that acts as an "off-on" ratio fluorescent probe for hydrogen peroxide (H2O2) detection was developed. The probe was used to measure the H2O2 concentration generated by mitochondria in vitro via recording the I-455/I-680 fluorescence ratio. Furthermore, this hybrid probe was applied to monitor the wound-induced H2O2 in lettuce leaf, and realized the visualized fluorescence qualitative detection H2O2 in vivo via laser scanning confocal microscope. The working mechanism of the probe is also investigated. Inner filter effect (IFE) estimation, Fourier transform infrared (FTIR) spectra and high-resolution transmission electron microscopy (HRTEM) images were applied to study the quenching mechanism and recovering reason of Si-O QDs fluorescence. The results show that the blue fluorescence of Si-O QDs can be quenched by Ag NCs via the IFE and fluorescent resonance energy transfer (FRET) effect. After adding H2O2, the surface groups of Ag NCs was changed and the IFE and FRET effects between the Si-O QDs and Ag NCs are disabled, thus the quenched Si-O QDs luminescence can be regularly recovered.

In this study, a biomimetic synthetic strategy was proposed for a facile preparation of red fluorescent silicon quantum dots (SiQDs) using unicellular algae of diatoms as reaction precursor.

Luminescent nanoparticles (upconversion nanoparticles, carbon dots, silicon nanoparticles and nanophosphors) have the advantages of tunable photoluminescence, good biocompatibility, low cytotoxicity and chemical/physical stability. Recently, the luminescent nanoparticles have been involved in the plant research for imaging plant phenotype and improving the photosynthesis efficiency. Luminescent nanoparticles are applied for the plant imaging in vivo and in vitro, while the plant photosynthesis is dependent on the specific light wavelength, providing the luminescent nanoparticles an opportunity to optimize the agriculture light. This review presents the recent developments of luminescent nanoparticles applied on the plant imaging and photosynthesis and discusses the trend for future research.

Eggplant (Solanum melongena) is a major vegetable crop worldwide. However, it is susceptible to bacterial wilt (BW) caused by Ralstonia solanacearum, which has become an important factor limiting eggplant yield and quality. The underlying mechanism of BW remains unknown. Here, RNA-sequencing was used to characterize the transcriptomes of resistant (R) and susceptible (S) strains before (R0, S0) and after (R1, S1) R. solanacearum inoculation. After the removal of low-quality sequences and assembly, 125,852 contigs, 122,508 transcripts, and 68,792 unigenes were identified, with 51,165 non-redundant unigenes annotated. Functional annotations were provided for 11,039 unigenes using four databases (NCBI Nr, Swissprot, KEGG and COG database). A total of 1137 and 9048 genes were found to be up- and down-regulated, respectively, in R0 relative to R1 samples, with 738 and 217 up- and down-regulated in S0 relative to R0 samples, 6087 and 5832 up- and down-regulated in S0 relative to S1 samples, and 4712 and 12,523 up- and down-regulated in S1 relative to R1 samples, respectively. In conclusion, our results provide useful insights into the potential mechanism of BW and are an important basis for further analysis.

High temperature (HT) stress affects the growth and production of cucumbers, but genetic resources with high heat tolerance are very scarce in this crop. Calmodulin (CaM) has been confirmed to be related to the regulation of HT stress resistance in plants. CsCaM3, a CaM gene, was isolated from cucumber inbred line "02-8." Its expression was characterized in the present study. CsCaM3 transcripts differed among the organs and tissues of cucumber plants and could be induced by HTs or abscisic acid, but not by salicylic acid. CsCaM3 transcripts exhibited subcellular localization to the cytoplasm and nuclei of cells. Overexpression of CsCaM3 in cucumber plants has the potential to improve their heat tolerance and protect against oxidative damage and photosynthesis system damage by regulating the expression of HT-responsive genes in plants, including chlorophyll catabolism-related genes under HT stress. Taken together, our results provide useful insights into stress tolerance in cucumber.

Eggplant (Solarium melongena L.) is an important vegetable crop and widely cultivated in China.The vitamin P in the eggplant is abundant and useful for human health.Selecting the high content of vitamin P of eggplant resource has crucial influence on the quality breeding of eggplant.This study used the UV spectrophotometer method to detect and compare the content of vitamin P in the 40 eggplant materials,the result showed that there were significantly different among the contents of vitamin P in the 40 eggplant materials.Meanwhile,the highest content of the pulp was (0.82±0.03) mg·g-1·FW-1,and the highest content in the peel reached (1.66±0.09) mg · g-1· FW-1,the content of vitamin P in pulp was higher than that it in peel.Furthermore,the content of vitamin P in the deep color fruit of eggplants was higher than that in the lighter color fruit.The results was useful to carry out quality breeding of eggplant.

Cucumber is the universal vegetable with great consumption.High temperature stress is the main adversity factor affected the production and quality of cucumber.It is important to select the heat resistant cucumber resource for solving the problem of cucumber growing and breeding heat resistant cucumber varieties.At present,the heat resistant cucumber resource is scarce.In this research 11 cucumber inbred lines were treated under 40℃ high temperature stress to screen the heat-resistant cucumber materials and build the system of selecting the heat resistant cucumber fastly.The results indicated that the leaves of heat-susceptible cucumber seedlings showed wilting and curly firstly,the plant death under 40℃ high temperature stress for 10 d,the heat resistance of cucumber seedlings could be identified clearly,the activities of antioxidant enzyme,the contents of malondialdehyde (MDA),glutathione (GSH) and the relative conductivity of cucumber seedling plants were increased significantly,but the content of ascorbic acid (AsA) was down.Compared with the heat susceptible cucumber plants,the contents of MDA and the relative conductivity were low,and the contentd of ascorbic acid and GSH were high in the heat tolerance cucumber plants.At the same time,the degradation of leaves tissue were acute,the lignin depositing of stems were reduced,the stoma showed a large opening state in the heat susceptible cucumber plant,but not in the heat tolerance plant.The dead rate of plant,the relative conductivity and the content of GSH of cucumber plant showed high relativity to the heat tolerance under heat stress.Two heat tolerance cucumber inbreeding lines were obtained,named as 05-41 and 02-4.The study selected the heat resistant cucumber for breeding,observed the changing of physiological index and morphological structure,and built system to select heat resistant cucumber expediently.It laid the foundation for deeply research later.