Abstract:In order to explore the characteristics and functions of the chitinase gene family (CHis), eighteen AcCHi genes were identified from Actinidia chinensis. The phylogenetic analysis showed that they clustered in GH18 and GH19 clusters and were divided into 6 groups with high similarity in conserved domain, gene structure and protein structure among the members. The cis-acting elements of AcCHi genes promoter region were mainly involved in hormone response, abiotic stress response and growth and development regulation. The 18 AcCHi genes were unevenly distributed on 12 chromosomes, and 5 of them had fragment duplication. The expression of AcCHis might be regulated by miR172 and miR408. In AcCHis, the transcription of GH18 members and GH19 members in different tissues, such as mature fruit, young fruit, leaf, stem, flower, was significantly different. During the storage of kiwifruit fruit, 90.9% of GH18 members had no or low expression, however, 71.4% of GH19 members showed differential expression. The expression of AcCHi8 in fruits was up-regulated at 25 ℃ for 1 week and at 4 ℃ for 1 to 3 weeks, and the expression of AcCHi8 was the highest at 4 ℃ for 3 weeks (188 times to the control), while the expression of AcCHi8 was down-regulated at 25 ℃ for 1 week after ABA soaking. Therefore, it was suggested that AcCHi genes might be involved in the process of storage and softening of postharvest fruits.

Abstract:To explore the response mechanism of Akebia trifoliata to acid rain stress and the effect of exogenous titanium [Ti(SO₄)₂] on its acid resistance, the changes in leaf anatomy and physiological characteristics were studied after simulated acid rain and exogenous titanium treatment, and the principal component analysis and correlation analysis were performed. The results showed that compared with the control, the lateral vein and epidermal structure of leaves were seriously damaged under simulated acid rain (T0) treatment, the main vein, main vein vascular bundle, leaf and palisade tissues were thickening, the chlorophyll content was significantly decreased, the oxygen free radical production rate, the activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) were significantly increased. Exogenous titanium treatments (T1-T3) effectively alleviated the damage of lateral vein and epidermal of leaves, significantly increased chlorophyll content, SOD, POD and CAT activities, and maintained a low rate of oxygen free radical production. Principal component analysis showed that main vein, vascular bundle and leaf thickness played a key role in response mechanism to acid rain stress. Correlation analysis showed that there were significantly positive correlations among vascular bundle thickness, palisade tissue thickness, leaf tissue structure tightness, activities of SOD, POD and CAT. Therefore, the seedlings of A. trifoliata could adapt to acid rain stress by changing the leaf anatomical structure and increasing the activities of SOD, POD and CAT. Appropriate Ti could effectively alleviate the damage caused by acid rain stress, and 0.2 mmol/L Ti had the best effect.

Abstract:Annamocarya sinensis is a national Class Ⅱ key protected wild plant with extremely small populations.To elucidate the genetic diversity and variation of wild A. sinensis population in Guangxi can provide guidance for the development of genetic diversity conservation and management strategies. The genetic diversity and genetic variation of 4 wild populations (47 individuals) in Guangxi were analyzed by using 6 pairs of SSR primers with good stability and polymorphism. The results showed that the average number of observed alleles was 2.125, the average number of effective alleles was 1.581, the average Shannon information index was 0.477, the average observed heterozygosity was 0.310, the average expected heterozygosity was 0.286, and the average allele richness was 1.677. The level of genetic diversity of A. sinensis in Guangxi was low. There was a moderate genetic differentiation among populations (0.120), accounting for 20% among populations and 80% within population. Structure and UPGMA analysis showed that the 47 samples could be divided into three categories, which were mixed with each other and had rich genetic background. The genetic diversity of Yongfu County population in Guilin City was the highest (He=0.339, I=0.598), which should be regarded as the key conservation unit.

Abstract:In order to explore the field resistance identification method of sweet potato (Ipomoea batatas) foot rot and to screen resistant germplasm, a total of 81 germplasms with resistance or other traits were identified after 1-3 years experiment, and the disease changes in different growth stages of sweet potato and the effects of different resistance grades on the yield loss rate of fresh sweet potato were analyzed. The results showed that among the 81 germplasms, 24 and 11 were highly resistant and resistant, respectively. From 90 to 120 d of growth stage, the disease changed obviously, especially the proportion of grade 4 disease of the susceptible species increased rapidly. There was a significant negative correlation between fresh potato yield and disease index (r= -0.978 1^**), and the average yield loss rate of fresh potato increased by 19.35% for each resistance grade decrease. At 120 d of growth stage, there was a significant positive correlation between incidence and disease index (r= 0.992 5^**). Therefore, in addition to disease index, incidence could also be used as an index to identify resistance to foot rot of sweet potato.

Abstract:To understand the function of CRABS CLAW (CRC) subgene of the YABBY gene family of Anoectochilus roxburghii in flower and leaf development, the ArCRC gene was cloned by RT-PCR based on the full-length transcriptome data of A. roxburghii. The bioinformatics, prokaryotic expression and subcellular localization of encoded ArCRC protein were analyzed, and the expression pattern of ArCRC gene was analyzed by qPCR. The results showed that the CDS length of ArCRC gene was 576 bp (GenBank accession No.: OR394646), coding 191 amino acids. ArCRC contains YABBY superfamily and HMG-box_SF superfamily conserved domain, with molecular weight 21.514 kD, theoretical isoelectric point 9.16, instability coefficient 41.12, belonging to the unstable protein. Phylogenetic analysis showed that ArCRC was clustered with OsDL of rice (Oryza sativa) and AtCRC of Arabidopsis thaliana, belonging to the CRC subfamily and localized in the nucleus. SDS-PAGE electrophoresis and Western blot results showed that ArCRC gene could be successfully induced in Escherichia coli. qRT-PCR analysis showed that the expression of ArCRC gene was the highest in flowers, followed by leaves, and the expression in the midrib of leaves was significantly higher than that in the margin of leaves. Therefore, it was speculated that ArCRC gene mainly played a role in the development of flower organs and was also involved in regulating the development of the midrib of leaves.

Abstract:In order to strengthen the protection of krummholz in Mulinzi Nature Reserve, its community structure and species diversity were analyzed by means of sample site survey. The results showed that there were 53 species of woody plants belonging 19 families 31 genera. Quercus glauca was dominant species, and Fagaceae and Ericaceae were dominant family in the community. Shannon-Wiener diversity index, Simpson dominance index and Pielou evenness index were 1.411, 0.559 and 0.522, respectively, indicating that the diversity of the community was low, and most plants were eliminated by the environment during succession. The community flora had an ancient origin, was deeply influenced by tropical flora with temperate character, showing obvious transition characteristics from subtropical to temperate zone. The diameter class structure of the community showed an inverted “J” type distribution, and the natural regeneration was good. The dominant species Q. glauca had a similar diameter class structure to the community, and occupied a dominant position in the succession process. Therefore, it would provide a theoretical basis for the protection, scientific management and later construction of the moss dwarf forest on the top of the mountain.

Abstract:In recent years, the frequency of global heat wave events has increased significantly, and the impact scope and duration have gradually expanded. Continuous high temperature and heat wave will seriously inhibit the growth of plants, resulting in plant wilt and even death. The effects of high temperature and heat wave on the growth of 105 species of subtropical garden plants were studied through field investigation, and the response degree of plants was analyzed according to plant functional groups and origin. The results showed that plant groups and habit affected the response to high temperature and heat wave. The wilt rate of gymnosperms was significantly higher than that of angiosperms under high temperature and heat wave, and 35.71% of gymnosperms suffered serious damage, while only 6.59% of angiosperms suffered serious damage. The blight rate of deciduous plants was significantly higher than that of evergreen plants, which 21.21% of deciduous plants were seriously damaged, and did only 5.17% of evergreen plants. Therefore, it was pointed out the direction for the protection and cultivation management of subtropical plants under high temperature and heat wave, and provided practical scientific recommendations.

Abstract:In order to explore the survival strategies of forest ecosystems under environmental change and predict the response mode of roots under the background of long-term nitrogen (N) deposition, two treatments, including control and N addition [80 kg N/(hm²·a)], were set up in subtropical natural evergreen broad-leaved forest to study the effects of long-term N addition on root biomass, specific root length, specific surface area and tissue density. The results showed that long-term N addition had no significant effect on root biomass and its root biomass reduction coefficient β (P>0.05), the vertical distribution characteristics of root biomass did not change significantly (there was no significant difference between biomass accumulated in different soil layers). The root biomass density of different diameter classes under control and N addition showed the same trend with soil layer, but the interaction between soil layer and diameter class had a significant effect on root biomass. Long-term N addition significantly increased 0-1 mm fine specific root length. However, long-term N addition significantly decreased the tissue density and was not affected by diameter class. However, N addition had no significant effect on the specific surface area of roots, and this change was an overall trend at the community level. At the community level, long-term N addition had no significant effect on the root biomass and vertical distribution of subtropical evergreen broad-leaved forest, which was consistent with the changes in total carbon (C), N and phosphorus (P) contents in soil with soil layer. However, N addition for 11 years increased the specific root length and decrease the tissue density, and the root resource acquisition strategy of some species changed to a rapid acquisition strategy. Therefore, under the background of long-term N deposition, roots would respond to nutrient changes by increasing specific root length and decreasing tissue density.

Abstract:Polyalthia s.l. is an important component of tropical and subtropical forests. Meanwhile, it’s a large taxonomically difficult genus of trees or shrubs in Annonaceae. There are 17 Polyalthia species in China according to Flora Reipublicae Popularis Sinicae and Flora of China. The most updated phylogenetic and taxonomic studies of Polyalthia were reviewed and summarized, and it was confirmed that the Polyalthia species previously recorded in China belong to nine genera, viz. Polyalthia s.s., Disepalum, Huberantha, Marsypopetalum, Monoon, Wangia, Wuodendron, Polyalthiopsis and Trivalvaria. An updated list of Polyalthia species recorded in China was provided with their accepted names. An illustrated phylogeny was provided to show the phylogenetic relationship of the nine genera. An identification key to the nine genera and related species in China was also provided. This synoposis of Polyalthia and related taxa in China would be helpful to deepen the understanding on the generic diversity of Annonaceae in China.

Abstract:In order to understand the differences of volatile components among different Begonia species, the volatile components from male flowers of Begonia kui, B. ornithophylla and B. barsalouxiae were determined and analyzed by headspace solid-phase microextraction-gas chromatography-mass spectrometry. The results showed that 97 volatile components were identified from three kinds of Begonia flowers, among which 30 were from B. kui, mainly heterocyclic compounds, did 56 and 44 from B. ornithophylla and B. barsalouxiae, respectively, most of them were alcohols. Principal component analysis (PCA) showed that there are obvious differences in the main aroma components of three Begonias. There were 15 key floral components screened out by partial least square discriminant analysis (PLS-DA), it was inferred that the aromas of B. kui were wax and balm type, that of B. ornithophylla were citrus type, and that of B. barsalouxiae were floral type. Therefore, the types and contents of main volatile components and main aroma substances of different Begonias species had great differences. Floral fragrances were formed by the interaction of various volatiles, and the aroma type is determined by the volatiles with a higher odor value.

Abstract:In order to explore the natural antifungal agent of controlling banana anthracnose, antifungal activity of Isodon serra extract against Colletotrichum musae was evaluated by inhibition of mycelia growth and controlling activity test on banana fruits, and the potential mechanisms were investigated by studying the effect of I. serra extract on the mycelia cell integrity, mycelia morphology and activity of enzyme related to energy metabolism. The results showed that ethanol extract of I. serra and its different polar solvent extraction fractions had obvious antifungal activity against C. musae. Among them, petroleum ether fraction had the strongest inhibitory ability, its medium inhibitory concentration on mycelia growth was 0.18 mg/mL. The test of controlling activity on banana anthracnose showed that different concentrations of petroleum ether fraction decreased the lesion diameter of banana significantly compared with the control group (P<0.05), and the lesion diameter of banana treated with the extract at 4 mg/mL had no significant difference with the positive control (P>0.05). The integrity of C. musae mycelia cell was damaged significantly after incubation with the petroleum ether fraction, leading to the increase of cell permeability, moreover, the plasmolysis, shrinkage and crack in mycelia were also observed, and the damage degree was concentration-dependent. The enzyme activities of succinate dehydrogenase, malate dehydrogenase, ATP synthase and ATPase decreased by 23.56%, 60.51%, 9.01% and 32.01% respectively with the petroleum ether fraction treatment. In conclusion, these findings suggest that the antifungal mechanisms of I. serra extract against C. musae could be attributed to the disruption of cell structure and the effect on enzyme activities related to energy metabolism. Isodon serra extract could be used as a potential fungicide of controlling banana anthracnose.

Abstract:The restoration of degraded ecosystems mainly includes the rehabilitation of degraded habitats and the restoration of biological communities, which is aligns with the forestry principle of ‘the right tree in the right place’. However, in afforestation and restoration of degraded ecosystems, inadequate consideration of this principle often results pool survival rates, low functionality, and sluggish pace of recovery. To ensure that the right tree is planted in the right place, a comprehensive approach to tree species selection is imperative. Beyond the fundamental guideline of utilizing native species, it is essential to account for the genetic diversity of tree species, the succession stage of tree species, plant functional groups, and plant functional traits at multiple scales. For suitable land, both the land use and land degradation level should be considered simultaneously. Based on the afforestation objectives, the land can be categorized into barren land for afforestation, commercial forest plantations or garden lands for transformation. Additionally, considering the level of ecosystem degradation, the land can be classified into extremely degraded, moderately degraded, and mildly degraded land. Under climate change, the criteria for the right tree in the right place may shift. If ecological restoration before climate change emphasizes restoring the historical state of ecosystems, the ecological restoration under climate change will undergo a certain degree of adaption. This adaptation includes the creation of adaptive habitats and the assistance of species migration or breeding that are more tolerance to climate change. Both of these strategies are crucial for effective restoration. Properly established vegetation through thoughtful tree planting can mitigate the impacts of climate change, conserve biodiversity, rehabilitate degraded ecosystems, and provide multiple ecosystem services. Ultimately, this approach supports the broader goal of sustainable development, and fostering a harmonious coexistence between humanity and nature.

Abstract:Plant lectin receptor-like kinases (LecRLKs), which belong to the family of plant receptor-like kinases, are a group of plant membrane protein receptors. LecRLKs are primarily composed of extracellular lectin domains, transmembrane domains, and intracellular kinase domains. They can be classified into G-type, L-type, and C-type based on the specificity of their extracellular domains. In plants, lectin receptor-like kinases play a significant role in regulating growth, development, and environmental responses. This article provides a comprehensive review of the research history, structure, and classification of lectin receptor-like kinases, systematical elucidation of their critical functions in plant growth, development, and responses to environmental stimuli, and categorization of genes with established functions. The article also discusses the limitations in previous lectin receptor-like kinase researches, including the lack of evolutionary history elucidation, unclear signal pathways, and unidentified ligands. Based on the current state of researches, the specific recommendations are proposed with the aim of providing theoretical support for targeted breeding within the gene family.