Rhododendron hainanense Merr. has high ornamental and ecological value. It is of great significance for the protection and application of this plant through the study of ecological requirement and applicable range. In this paper, MaxEnt model and ArcGIS were used to simulate the potential geographical distribution of R. hainanense in China, based on the existing geographic distribution information, climate factors of this plant. And the key environmental factors, affecting the potential distribution of R. hainanense and suitable thresholds are analyzed. The results showed that under the contemporary climate scenario (1970—2000), the maximum entropy model (MaxEnt) can predict the suitable area of R. hainanense with high accuracy. The temperature and precipitation have a great influence on R. hainanense. The main factors affecting the potential distribution of R. hainanense are precipitation of warmest quarter (bio18) and mean diurnal range (bio2). When the precipitation of warmest quarter (bio18) is between 610-3990 mm and the mean diurnal range (bio2) is 5-7 ℃, the climate environment is suitable for the growth of R. hainanense. In a certain range, the probability of presence of R. hainanense will increase with the increase of precipitation. In China, the suitable habitat area of R. hainanense is mainly distributed in Hainan, Guangxi, Guangdong, Taiwan, eastern Sichuan, Chongqing and Guizhou. The total suitable habitat area of R. hainanense under contemporary climate scenarios is 132.36×10⁴ km². The purpose of this paper is to provide a scientific basis for the protection and application for the species.

The main taste components of six different coffee beans from various regions in Hainan, including Xinglong coffee beans (XL), Fushan coffee beans (FS), Qionghai coffee beans (QH), YSL coffee beans from Baisha Yushiling (YSL), MS1 coffee beans from Mushan No.1 (MS1), and MS2 coffee beans from Mushan No.2 (MS2) were studied. Differences in taste composition and component content of the roasted coffee beans from different regions were compared. Based on the chemical characterization of the beans using the fingerprinting of the main taste components, the influence of the origin on the taste characteristics components of coffee beans was investigated and the roasted beans were distinguished. The levels of eight chlorogenic acids, caffeine, trigonelline and eight organic acids in the roasted beans were measured using ultra-high performance liquid chromatography (UPLC), while the composition and content of monosaccharides in the coffee samples were determined using pulsed amperometry by ion exchange chromatography (HPAEC-PAD) and the composition and content of amino acids were determined using an automatic amino acid analyser. The results showed significant differences in the content of taste components among the roasted beans, with the highest content of caffeine and trigonelline found in MS2 beans and the lowest in MS1 beans. The highest content of amino acids was found in QH beans, while the lowest content of chlorogenic acids and monosaccharides was found in QH beans. The content of chlorogenic acids in the roasted beans was as follows: caffeoylquinic acids (CQAs)>feruloylquinic acids (FQAs)>dicaffeoylquinic acids (diCQAs). Only eight monosaccharide components were detected in the six varieties, with the highest content of galactose. Based on principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA), the six coffees beans were successfully discriminated, with high similarity between the XL coffee beans, YSL and MS2 coffees beans, indicating that the major chemical taste components can be used to distinguish coffee beans from different regions of Hainan. The results show that the fingerprinting of key taste components can effectively distinguish coffee beans from different regions. This study would provide information on the chemical composition and quality characteristics of coffee beans from different regions and provide a theoretical basis for improving coffee flavour quality, which is important for the screening and differentiation of high-quality coffee samples.

The effect of composite passivators on the in-situ Cd contaminated soil and its absorption and accumulation of Cd in cabbage were explored, which would provide a scientific basis for the treatment and restoration of medium and mild Cd contaminated farmland. Field experiments were carried out in Cd polluted farmland soil with five passivator combinations: red mud + lime + phosphate rock powder (T₁), red mud + lime + biochar (T₂), lime + humic acid + sepiolite (T₃), sepiolite + biochar + red mud (T₄), sepiolite + biochar + phosphate rock powder (T₅), in order to study the effects of the five passivating agent combinations on the content of various forms of Cd, enzyme activity, microbial carbon (MBC), microbial nitrogen (MBN) and the absorption and accumulation of Cd in various parts of Chinese cabbage in the cultivated layered soil. The five compound passivating agents could improve soil pH and reduce the availability of Cd in the soil in different degrees. Soil pH in T₃, T₄ and T₅ treatments was significantly higher than that in CK, and soil available Cd content in T₂, T₃, T₄ and T₅ treatments was significantly lower than that in CK. In each form of Cd, in T₅ treatment, the content of Cd in weak acid extraction state and reducible state was significantly higher than that in CK, while the content of Cd in residue state was significantly lower than that in CK. Compared with CK, T₁, T₃, T₄ and T₅ treatments significantly increased soil sucrase and acid phosphatase activities by 42.06%-152.46% and 15.95%-26.48%, respectively. Treatments T₁, T₂, T₃ and T₄ significantly increased urease activity by 18.43%-35.19%, treatments T₃ and T₄ significantly increased catalase activity by 18.78%-19.01%, treatments T₁, T₂ and T₃ significantly increased soil MBC content by 31.83%-53.19%. T₂, T₃ and T₄ treatments significantly increased soil MBN content by 19.14%-59.89%. Different treatments had different effects on Cd absorption and accumulation in different parts of Chinese cabbage. Compared with CK, T₄ and T₅ treatments significantly reduced Cd content in roots, T₁, T₄ and T₅ treatments significantly reduced Cd content in stems, and the five treatments significantly reduced Cd content in leaves, and the enrichment and transport capacity of Cd in leaves of Chinese cabbage was greater than that in stems and roots. In terms of comprehensive passivation effect, T₄ and T₅ treatments, namely sepiolite + biochar + red mud (3∶5∶3), sepiolite + biochar + phosphate powder (3∶5∶3), had better passivation effect in the field soil mildly polluted by Cd during in-situ passivation restoration, which could effectively reduce the absorption of heavy metal Cd in soil by plants.

Rice (Oryza sativa L.) is an important food crop, and the normal germination of rice seeds is related to the growth and yield of the plant in the later period. The germination begins with water absorption by dry seeds and ends with cotyl elongation. Water transport within and between cells is highly selectively regulated by aquaporins (AQPs). The seeds of cereal are rich in starch. And the endogenous gibberellin can induce the synthesis of hydrolase such as α-amylase in the embryo and secrete them into the starchy endosperm to degrade starch into small molecules for seed germination. Studies have shown that only α-amylase can complete the degradation of starch in rice seeds. Nitric oxide (NO) is a signaling molecule that forms a variety of active nitrogen substances. It also participated in the signaling process of seed dormancy removal. NO donor plays a role in seed germination by enhancing amylase activity. NO donor can promote seed germination by improving the activity of amylase. Rice hybrid seeds of ‘BoⅡ you 767’ were used as experimental materials to investigate the effects of aquaporins (AQPs) and nitric oxide (NO) on the germination of rice seeds. In this study, NO synthesis inhibitors N-(G)-nitro-L-arginine methyl ester (L-NAME) and sodium tungstate (ST), sodium nitroprusside (SNP), an exogenous donor of NO, and mercury chloride (HgCl₂), an activity inhibitor of AQPs, were used to treat rice seeds. The changes of water absorption capacity, amylase activity and starch degradation rate during germination of rice seeds were determined in virtue of apparent analysis and index detection. The results showed that the water absorption capacity, amylase activity and germination rate decreased in the rice seeds treated with 90 mg/L HgCl₂, while the starch content remained high, and the growth of radicle and germ was inhibited. However, NO exogenous donor SNP could reverse the effect of HgCl₂. And the effect of NO synthesis inhibitors L-NAME (15 mmol/L) and ST (80 µmol/L) on the germination of rice seeds was similar to that of HgCl₂. The results indicated that AQPs could induce water uptake, stimulate amylase, accelerate starch degradation and promote seed germination in the early germinating stage of rice seeds through NO. The study would lay a theoretical foundation for improving rice yield.

Gypsophila paniculata L. is one of the most popular and bestselling cut flowers in the world. Stem rot is among the common disease of G. paniculata L. causing plant withering and death in serious cases, affecting the ornamental and utilization value of the flowers and causing certain economic losses. In March 2021, a severe wilt due to stem rot was observed on G. paniculata L. in Haikou town, Kunming, Yunnan, China. The disease mainly affected the stem base which was manifested by rot on stem base and wilting. In order to identify the pathogenic microorganism, we isolated and identified the pathogen associated with the stem of G. paniculata L.. Koch’s postulates proved that the isolate caused similar symptom on tissue culture and potted seedlings of G. paniculata L., and the isolate had similar morphology with initially isolated from with the naturally infected seedlings in the field. Through morphological identification, the isolate produced a large number of dense aerial hyphae with color ranging from white to light orange or yellow with dark red pigment deposition on the back of the colony. The conidia of the isolate was sickle-shaped with flat ventral side, the dorsal side was arched, with three to six septation. The macroconidia was in the range (21.1-57.9)µm×(2.7-5.1)µm (n=100), no microconidia were observed. The morphology was similar to that of Fusarium pathogenic fungi. Through the identification of ITS gene sequence and morphology, the isolate was initially identified as F. graminearum species complex (FGSC). In order to further identify the subspecies, the TEF-1α sequence was used for sequencing. It was found that the isolate was 100% homologous with F. meridionale. Therefore, combined with morphological and molecular biological characteristics, the pathogen of the stem rot of G. paniculata L. was identified as F. meridionale. This is the first report on the stem rot of G. paniculata L. in China, which would provide an important basis for the prevention and control of the disease.

A nitrogen fixing bacteria strain named BWLY3X-6 was isolated from the rhizosphere soil of wild banana (Musa nana Lour. sp) in Hainan, China using Ashby nitrogen free medium, and .its morphological characteristics, physiological and biochemical characteristics, 16S rRNA and gyrB sequence analysis, nitrogen fixation characteristics and growth promoting ability to different banana varieties were studied. The strain was identified as an azotobacter Klebsiella variicola, and its extracellular ammonia nitrogen content was (17.98±1.88)μg/mL, nitrogenase activity was (220.51±8.21) ng/L. The results of the growth promoting test of the strain on different banana varieties showed that, compared with the blank control and 0.5% urea treatment, after inoculation with BWLY3X-6, under the inoculation concentration of 10⁶ CFU/mL and 10⁸ CFU/mL, there were significant changes in various biomass of M. acuminata AAA Cavendish cv. Nantianhuang and M. acuminata AAA Cavendish cv. Baxi (P<0.05), with more significant changes in root length, with the increase ratio of 43.5% and 54.6% respectively. In this study, nitrogen fixing bacteria with good nitrogen fixing ability were screened, and this strain had a good promoting effect on banana growth, wihich would provide a theoretical basis for its subsequent practical application in agricultural production.

The effects of water management and foliar spraying of exogenous plant hormone ethylene (ETH) on the accumulation of rhizosphere iron membrane, cadmium (Cd) and health risk index of rice were studied. Through the potting test, two concentrations (50 μmol/L and 100 μmol/L) ethylene (ETH) were sprayed three times at the jointing stage, the flowering stage and the grouting stage, and the water management modes of continuous flooding (CF) and interval flooding (IF) were adopted. Compared with the IF water management mode, the storage morphology of Cd in the soil was changed in the CF water management mode, and the soluble Cd was reduced from 36% to 30%, and the reducing state Cd was increased from 30% to 40%. Compared with the IF water management mode, the Fe and Cd content in the rice root surface iron film were significantly increased in the CF water management mode, and the exogenous spraying of ETH also significantly increased the Fe and Cd content in the iron film under the two water management modes, up to 50.59% and 58.06%. Compared with the IF water management mode, the Cd content in rice roots, leaves, brown rice and polished rice decreased significantly under the CF water management mode. The external spraying of ETH was also conducive to reducing the cadmium content of rice under the two water management modes, among which the Cd content in polished rice under CF+50ETH treatment was the lowest, and the Cd content in polished rice decreased from 0.68 mg/kg to 0.45 mg/kg, a decrease of 33.82% compared with CF treatment. Exogenous spraying of ETH significantly reduced the transport coefficients of Cd from rhizome and stem-grain under the two water management modes, and the transport coefficients were the lowest under CF+50ETH treatment, which was reduced by 55.17% and 23.81% respectively compared with CF treatment. CF water management mode and spray ETH treatment have a good effect on reducing the health risk index of rice Cd. It can be seen that CF water management mode and exogenous spraying of ETH have certain application prospects for reducing the accumulation of Cd in rice.

Cordyceps chanhua is an important Chinese traditional medicine and food, that has important application value in the development of green functional food and new resource drugs. Taking one wild fungi Chanhua collected from Qujing of Yunnan province as the experimental material, the biological characteristics and artificial cultivation conditions were studied for the purpose of domestication and cultivation. Based on the morphological anatomy and molecular phylogenetic analysis, a wild ascomycetes was identified as C. chanhua. The biological characteristics and domestication of C. chanhua strain were studied by single factor experiments and orthogonal tests. The result showed that the branch stalk of C. chanhua was orange yellow or yellow white, (8.0-28.0) mm×(1.5-3.0) mm, and the conidia was oblong, (4.0-8.5)µm×(1.5-3.5)µm. The optimum temperature for the mycelial growth was 24 ℃, the optimum pH value was 6, the carbon source, nitrogen source and mineral salt was sucrose, yeast powder and magnesium sulfate respectively. The results of orthogonal test based on three factors under the optimum pH value and temperature showed that carbon source had the greatest impact on the mycelial growth, followed by nitrogen source and mineral salt, with range 1.21, 0.39 and 0.13 respectively. Therefore, the optimal combination of factors for the mycelial growth of C. chanhua was sucrose 20 g/L, yeast powder 2 g/L and magnesium sulfate 2 g/L. The artificial cultivation of C. chanhua utilized the 1∶1 mixed medium of wheat and rice, and the harvest cycle of fruiting body was about 40-45 days, and the average dry weight of each cultivated Chanhua was about 9.56 g. The external morphological characteristics of artificially harvested C. chanhua were significantly different from those of wild fruiting body. The fruiting body was yellowish to light yellow, with few branches, 1.5-5.0 cm in length, 0.3-0.8 cm in width and 0.1-0.2 cm in depth. The sporangium bundles were covered with dirty white flocculent or powdery conidia. The screening of excellent strains and optimal culture conditions of C. chanhua would provide a theoretical basis for its study on the diversity of germplasm resources, protection and utilization.

Curcuma alsimatifolia is a perennial bulbous herb of the genus Curcuma in the Gingeraceae.family The inflorescence of C. alismatifolia resembles tulips and enjoys the reputation of “tropical tulips”. C. alsimatifolia was introduced into China from Thailand and it is acclaimed by an ever-increasing number of consumers. The varieties of C. alismatifolia are relying on import in China today. The lack of new varieties with proprietary intellectual property rights limits the development of C. alismatifolia industry in China. Three different cross combinations of 327 hybrid offspring were constructed using the Siam TM Sitrone variety of C. alismatifolia as the female parent to breed new varieties of C. alismatifolia with independent intellectual property rights and increase the variety diversity. Eleven pairs of SSR primers were selected to analyze the hybrid F₁ generation of the three cross combinations and the parents, and five pairs of specific SSR primers were selected for each cross combination to identify the authenticity of the hybrid F₁ generation. The genetic segregation pattern and genetic diversity and genetic relationship of the parental and hybrid F₁ generation populations were also analyzed. The results showed that the eleven pairs of SSR markers had high resolution and good amplification polymorphism for the three parental materials, and each parent had its specific SSR markers, which could effectively identify the genetic authenticity of the hybrid offspring. True hybridization rates of 91.8%, 90.8% and 93.4% were identified in 327 F₁ individuals The SSR molecular marker primers had high polymorphism and could be directly used for C. alismatifolia genetic diversity analysis, hybrid identification and other related studies, providing efficient and reliable SSR marker selection for future identification of hybrid progeny, while the identified true C. alismatifolia progeny population could provide germplasm for genetic studies of superior traits. The identification of authentic C. alismatifolia progeny could provide germplasm materials for genetic research on superior traits and provide scientific basis for the selection of new varieties.

Oryza officinalis Wall. ex G. Watt has excellent characteristics such as disease and insect resistance, stress tolerance, high biological yield and high light efficiency, and contains many excellent genes. In this study, 199 representative resources collected from all Oryza officinalis distribution sites in Guangxi were used to analyze the genetic diversity and principal components for five important agronomic traits, including heading stage, anther length, grain width, grain length and grain weight. The results showed that O. officinalis from Guangxi had rich genetic diversity, with coefficients of variation of 9.12%, 11.90%, 3.39%, 4.64% and 6.24% for heading stage, anther length, grain width, grain length and grain weight, respectively, and diversity index was 1.4878, 2.0453, 1.7727, 1.1567 and 2.0379, respectively. Principal component analysis showed that the first and second principal components were mainly related to yield traits, with a cumulative contribution rate of 63.759%. The third and fourth principal components had a cumulative contribution rate 16.306% and 15.542%, respectively. The heading stage and anther length were the influential determinants, mainly reflecting the plant growth characteristics. According to the genetic diversity, the seven geographic populations are ranked as follows: Wuzhou (1.6731)>Yulin (1.5784)>Guigang (1.5070)>Nanning (1.3325)>Laibin (1.2131)>Hezhou (0.9629)>Qinzhou (0.3819), and Wuzhou had the highest diversity index, indicating that Wuzhou was the phenotypic diversity center of Oryza officinalis in Guangxi.