White-fruited pepper is a highly distinctive type of pepper in Zhejiang province. In order to determine the optimal nitrogen level for this variety, a facility cultivation experiment was conducted to analyze the effects of five different nitrogen treatments: 0 kg/hm², T₀; 150 kg/hm², T₁; 195 kg/hm², T₂; 240 kg/hm², T₃; 285 kg/hm², T₄, on the growth, development, quality and accumulation of nitrogen elements in white pepper plants. The results showed that the main stem height, plant height, canopy width, stem diameter, stem and leaf biomass and yield of peppers increased with the application of nitrogen. Notably, fruit width, single fruit weight and yield reached the maximum under the T₄ treatment, with increased of 36.27%, 76.30% and 32.16% respectively compared to the control, followed by T₃, while the T₃ treatment produced the longest fruits. Furthermore, the photosynthetic capacity of the pepper leaves improved with higher nitrogen application, with T₃ and T₄ treatments showing significantly better performance than the others. The quality of peppers was also influenced by nitrogen application. Nitrogen application also affected the quality of the pepper. The content of vitamin C and dihydrocapsaicin decreased with the increasing nitrogen levels, while the levels of capsaicin, total capsaicin and amino acids showed a trend of first increasing and then decreasing. Different nitrogen levels had a minor impact on nitrogen absorption in the roots, stems and fruits of peppers, but significantly affected nitrogen absorption in the leaves, with the T₂ treatment achieving the highest leaf nitrogen content. Through principal component analysis of the 10 indicators related to yield and quality, the optimal nitrogen application for white-fruited peppers is T₃ (240 kg/hm²).

Citrus medica is an older cultivated varieties of the genus Citrus and the parent or ancestor of Citrus fruits with significant commercial value. Due to its nutritional and medicinal values, C. medica occupies an important position in the citrus industry. The southwestern part of China is an important center for the origin and diversity of C. medica, and its cultivation has reached a certain scale. Citrus Huanglongbing (HLB) has been spreading for hundreds of years in the major citrus-producing areas in China. C. medica infected with HLB and healthy C. medica were used as the materials. Firstly, the symptoms of the leaves and fruits of C. medica infected with HLB were observed. Secondly, the distribution pattern of HLB in different tissue parts of C. medica was explored. Meanwhile, the tissue anatomical structures and multiple physiological indicators of C. medica infected with HLB and healthy C. medica were analyzed and measured through comparison. Through comparative observation, it was found that the leaves of C. medica infected with HLB showed typical symptoms such as yellowing, mottling and mosaic, and some branches presented symptoms of witches broom and abnormal flowering, but no “red nose fruit” was observed. The distribution of HLB in different parts of the same C. medica was uneven, with the highest content in the fruit pith, followed by the midrib of the old leaves, and HLB was not detected in the fibrous roots. In C. medica infected with HLB, the cells in the phloem, xylem, parenchyma and root were arranged irregularly, the phloem tissue was deformed and collapsed, and the thickness of the phloem of the taproot was significantly decreased compared with that of the healthy C. medica at the same period (P<0.05). No obvious starch grain accumulation was observed in each tissue section of C. medica infected with HLB, but when the starch content was measured, it was found that the starch contents in the old leaves, new leaves, taproot, fibrous roots and fruit pith of C. medica infected with HLB were all higher than those of the corresponding healthy tissues. The hydrogen peroxide content in each tissue of the diseased C. medica increased significantly (P<0.5), especially significantly accumulated in the young tissues (new leaves, fibrous roots) infected with HLB. Compared with healthy C. medica, the callose deposition phenomenon in the tissues of C. medica infected with HLB, especially in the main root and the midrib of the old leaves, was more obvious. The research results of this study could provide a theoretical basis for the relevant studies on exploring the characteristics of damage caused by HLB and the defense mechanism of citrus against HLB in the future.

Based on the data of rice growth period in Dongfang and Ledong, main producers for rice seed reproduction in Hainan, and the meteorological data from 1971 to 2020, the Penman-Monteith formula and crop coefficient method and the method recommended by the Soil Conservation Service of the United States Department of Agriculture were used to obtain the water requirement (ET_c), effective precipitation (P_e) and water deficit (D_w) of rice seed reproduction in field period and early, middle and late stage of field period. The change characteristics of water supply and demand of rice seed reproduction in the two regions were then analyzed. The 50-year average value of ET_c in field period of rice seed reproduction in Dongfang and Ledong was 400.2 mm and 322.3 mm, respectively, the mean value of P_e was 45.7 mm and 84.3 mm, respectively, and the mean value of D_w was 354.5 mm and 238.0 mm, respectively. The ET_c and D_w in field period of rice seed reproduction were mainly distributed in the middle and early stages, accounting for 72.4% to 85.2% of ET_c and D_w during the field period. The P_e in field period of rice seed reproduction was mainly distributed in the late and middle stages, accounting for 78.2% and 85.6% of P_e during the field period, respectively. In the past 50 years, the ET_c and D_w of rice seed reproduction in field period and all growth stages of field period in Dongfang showed an increasing trend (the increase in field period was significant), while the P_e showed a decreasing trend. The variation trend of ET_c, P_e and D_w of rice seed reproduction with time in Ledong was roughly opposite to that in Dongfang. In the past 50 years, the water shortage situation of rice seed reproduction in Dongfang was significantly worsening, while the water shortage situation in Ledong was easing to some extent but remained severe. Effective measures should be taken to mitigate the impact of climate change on the rice seed reproduction. In the past 50 years, the main reasons for the increase of ET_c and D_w during most growth stages of rice seed reproduction in Dongfang were the insignificant increase in high temperature and extremely significant increase in low temperature, or the insignificant increase in high temperature and sunshine hours. The main reasons for the decrease of ET_c and D_w during most growth stages of rice seed reproduction in Ledong were the insignificant decrease in sunshine hours, extremely significant decrease in average wind speed, or insignificant decrease in sunshine hours and insignificant increase in precipitation. The results of this study provide strong support for rational water use and scientific irrigation scheme for rice seed reproduction in Hainan province under the background of climate change.

Tea plants (Camellia sinensis) is an essential economic crop in China with significant genetic diversity. Polyploidization, a key driver in species evolution, plays a crucial role in enhancing the economic traits of tea plants, providing new avenues for breeding improved varieties. This study aims to explore the ploidy differences between diploid and triploid tea plants by investigating the morphological, physiological, biochemical and metabolic traits. Utilizing flow cytometry, we identified the chromosome ploidy of 165 tea germplasm resources and discovered 11 new triploid tea plant varieties. The 11 triploid varieties, along with 12 diploid varieties, underwent a comparative study focusing on bud, leaf and anatomical characteristics. The results revealed significant differences between diploid and triploid tea plants in several traits, including phenological period, bud weight, leaf area, stomatal size and stomatal density. Triploid tea plants generally exhibited later budding, significantly higher bud weight, larger leaf areas, and larger stomatal dimensions, but lower stomatal density compared to diploid varieties. As the buds and leaves are vital for tea quality, the morphological and physiological differences can influence tea production and its overall quality. Furthermore, metabolomic analysis using UPLC-MS/MS technology was conducted on the triploid variety Xilianno. 1 and its maternal diploid Fuding Dabai (CK). A total of 1203 differential metabolites were detected, with 170 showing significant variation, of which 81 were upregulated and 89 were down regulated. The most abundant metabolites were flavonoids, followed by amino acids and their derivatives. The triploid variety displayed enhanced levels of metabolites associated with improved antioxidant activity and other health-related properties. The study would provide novel insights into the morphological, physiological and metabolic differences between diploid and triploid tea plants, offering valuable references for genetic assessment and breeding strategies. The findings also emphasize the significance of polyploidy in improving tea plant resilience, yield and quality, which is critical for the sustainable development of the tea industry.

Lodging was one of the important limiting factors for high yield, high sugar content and mechanized harvesting of sugarcane, and it was also an urgent problem to be solved in sugarcane mechanized breeding. In this study, 24 reciprocal hybrids of 57NG208 and Nanjian chewing cane and PT43-52 (CK) were used as research materials. The plant height, basal stem diameter, middle stem diameter, brix, center of gravity height, single stem weight, the lodging resistance index, basal and middle stem diameter ratio and stem breaking force were measured. The correlation analysis, principal component analysis, membership function method and cluster analysis were used to comprehensively evaluate them. The results showed that the coefficient of variation of 9 indexes such as lodging resistance index and agronomic traits of 25 materials was between 11.57% and 30.80%, and the traits were obviously separated and the variation was abundant. The correlation analysis showed that the lodging resistance index was significantly positively correlated with brix, basal stem diameter, basal and middle stem diameter ratio, center of gravity height, single stem weight and stem breaking force, and negatively correlated with plant height and middle stem diameter. The results of principal component analysis showed that the cumulative contribution rate of the first three principal components was 75.7717%, which represented most of the information of lodging resistance of the tested materials. Cluster analysis showed that 25 materials could be clustered into three categories, and the results were consistent with the results of membership function evaluation. Among them, 13 materials in the first category had excellent lodging resistance and high comprehensive evaluation scores, especially Yunrui 12-9-45, Yunrui 12-9-5, Yunrui 12-38-32, PT43-52 and Yunrui 12-38-46. The lodging resistance index of the remaining germplasms was 3.00 except Yunrui 12-38-46, and the comprehensive evaluation E value was in the top 5, which should be used in the future improvement of lodging resistance.

Enhancing photosynthesis is the key to improving crop yield and quality. The interaction between agronomic traits, photosynthetic parameters, and variety yield and quality is not yet clear. In this study, 10 different mulberry varieties (Morus sp.) were taken as the research objects. Based on the morphological data such as leaf size, the number of leaves, the number of branches, etc., obtained through the statistics of our research group, the nutritional index data such as crude protein, and the measured photosynthetic parameters, we analyzed the correlations of specific parameters within each index through correlation analysis. And we utilized the structural equation model to analyze the influence mechanism and contribution potential of their agronomic traits, stomatal characteristics, and photosynthetic indexes on the yield and quality of mulberry leaves. There were significant differences in stomatal characteristics and photosynthetic indicators among different varieties, and Sha 2×Lun 109 exhibited good photosynthetic capacity and water use efficiency. There was a significant correlation between intercellular carbon dioxide concentration and leaf length, leaf width, and total calcium content. There was a strong positive correlation between stomatal length and width (r=0.833), and a positive correlation between crude protein content and leaf weight (r=0.660). The structural equation model indicated that the stomatal characteristics had a negative effect on leaf quality (R²=–0.75), while the intercellular carbon dioxide concentration had a negative effect on net photosynthetic rate (R²=-0.91). The intercellular carbon dioxide concentration and net photosynthetic rate directly affected leaf yield (R²=2.99 and 3.04, respectively), and leaf yield had a positive effect on leaf quality (R²=0.66). The research shows that mulberry varieties affect the net photosynthetic rate through stomatal characteristics and intercellular carbon dioxide concentration, which further affects the yield and quality of mulberry trees. Therefore, by regulating the parameters of mulberry stomata, the yield and quality of mulberry trees can be improved, which would provide a scientific basis for mulberry variety improvement and precision cultivation management, and has important practical significance.

In order to select a new tobacco variety with excellent industrial and agricultural characteristics was selected, the tobacco variety Y87 was used as the control to compare and analyze the agronomic traits, ultrastructure, metabolites and post baking tobacco quality evaluation of four newly introduced tobacco varieties Y121, Y116, Y301 and Y119. The results showed that Y121 had relatively good field growth, complete chloroplast structure, and a large volume and quantity of osmium loving particles on the chloroplast membrane. Through metabolic pathway enrichment analysis, it was found that Y121 contained more organic acids such as succinic acid and phenylacetic acid, as well as fewer nicotine such as nicotine reducing and new tobacco alkaloids, which are beneficial for improving the aroma quality and safety of tobacco leaves. In addition, compared to other newly introduced varieties, the Y121 had better appearance quality, more coordinated chemical composition, higher sensory quality score, and is closer to Y87. The results would provide reliable technical support for the upgrading of varieties, which is conducive to the sustained and stable development of high-quality raw material production.

Natural rubber in the storage, transport process of rubber molecular chain on the aldehyde group condensaion reaction, results in the plasticity initial value, mooney viscosity and other indicators gradually increased, plasticity retention rate gradually decreased, making it more difficult to increase the plasticizing and mixing processes of natural rubber, and reduces the oxygen aging resistance of the rubber. It is necessary to prepare natural rubber with constant viscosity to reduce the condensation of aldehyde groups in the molecular chain of natural rubber. Alkylhydrazine (OP) solution was used to soak natural rubber by microbial coagulation to analyse the effects of OP solution concentration and wet film soaking time on the physical and chemical indexes, vulcanization characteristics, physical and mechanical properties of natural rubber, plasticity initial value, plasticity retention rate and mooney viscosity hardening value of natural rubber during storage. The results showed that plasticity initial value and mooney viscosity of natural raw rubber increased first and then decreased with the increase of the concentration of OP solution, but the plasticity retention rate was opposite. During the accelerated storage process, the plasticity initial value and mooney viscosity of natural raw rubber soaked in different concentrations of OP solution increased, while its plasticity retention rate decreased. With the increase of OP solution concentration, the hardening value of plasticity initial value, plasticity retention rate and mooney viscosity gradually decreased. With the concentration of OP solution ≥0.5%, the hardening value of plasticity initial value and mooney viscosity were ≤5. The effect of wet film soaking time on the physical and chemical indexes of natural raw rubber and the hardening values of the plasticity initial value, plasticity retention rate and mooney viscosity was not obvious. Compared with the control sample P₀, the natural rubbers (P₇, P₈, and P₉) soaked in 0.5% concentration of OP solution had slightly higher torque difference values ΔM of their blends, the tensile strength and tear strength of vulcanized rubber increased by 4.5%–14.2% and 3.0%–8.5%, respectively. In addition, the soaking time of wet film had a significant effect on the torque difference ΔM of the rubber and the tensile strength and tear strength of the vulcanized rubber. OP solution had a good constant viscosity effect on natural rubber. 0.5% concentration of OP solution soaked natural rubber had excellent physical and mechanical properties, and the production process was simple, not causing the waste of constant viscosity agent and the pollution of the production workshop, surrounding environment, easy to large-scale promotion and application.

To generate polyploid B. ochracea Schltr and find out the optimal induction condition, the seeds of diploid B. ochracea were treated with different concentration of colchicine solution under a range of treatment time. The results of the study suggested that the seeds treated with 0.25% colchicine solution for six days was effective in polyploid induction for B. ochracea, with a 35.66% survival rate of treated seeds and a 45% induction rate. The tetraploid gave a significant enhancement on various agronomic traits, including plant height, leaf number, leaf width, stem diameter, bulb length and root diameter. In addition, tetraploid B. ochracea showed increased stomatal aperture and decreased stomatal density. The tetraploid B. ochracea was generated in this study, which would provide technical support and basic material for improving the genetic traits of medicinal orchids.

Heat shock transcription factor (HSF) is an important regulatory factor that plays a crucial role in plant response to hot ambient temperature (HAT). High temperature stress has a serious negative impact on the flowering of passion fruit, therefore, studying the regulation of heat tolerance by HSF in passion fruit is of great significance. In this study, we identified 26 HSF genes on the genome of passion fruit using bioinformatics technology, named PeHSF1-PeHSF26. The genes could encode proteins of 100-1589 amino acids, with molecular weight 11 544.9-177 157.8 g/mol, and a theoretical isoelectric point of 4.25-10.80. The 26 genes were distributed on chromosomes 1, 4, 5, 6, 7, 8 and 9, and were divided into 10 subpopulations. The analysis of the whole genome replication event showed that ZX01G0033270, ZX01G0052790 and ZX01G0052980 were located within the genome duplications. The genes contained 1-12 introns and 2-13 exons, all contained HSF-DNA binding domains. RNA-seq analysis of Huangguo original species and Jinlingziguo HSF genes to HAT revealed that there were significant differences in the expression levels of genes, including ZX01G0002530, ZX01G0052790 and ZX01G0121040 in flower buds. The expression levels of candidate HSF genes were validated by RT-qPCR. Based on comprehensive analysis, it is supposed that the most ideal candidate HSF gene for passion flower response to high temperature stress was ZX01G0121040. The results would contribute to understand the function of HSF in response to high temperature stress during the flowering of passion fruit, and provide important genetic resources and theoretical basis for genetic improvement of passion fruit.