Abstract:In this study, transgenic tobacco with color potato StAN1 gene was used as the material, and the wildtype tobacco (WT) was used as the control. The tolerance of the transgenic StAN1 gene tobacco to drought (mannitol) during the seed germination, shoots and seedling stages, and the tolerance to drought and heat common stress in the seedling stage was measured and analyzed, so as to explore the function of the StAN1 gene of colored potato and provide a new path for droughttolerant colored potato breeding. The results showed: (1) the positive rate of StAN1 transgenic tobacco was 82.6%, the leaves of transgenic tobacco were obviously purple, and the anthocyanin content was significantly higher than that of wildtype tobacco. (2) When the mannitol concentration in the medium was 150 mmol/L, the germination rate of the transgenic tobacco on the medium reached 7% on the 5th day, which was 2.3 times of wildtype tobacco. (3) When cultured vertically on the medium with mannitol concentration of 0 and 100 mmol/L, the root length of transgenic tobacco was 1.46 and 1.30 times of wildtype tobacco, which was significantly longer than that of wildtype tobacco. (4) Under drought stress, the proline content and superoxide dismutase activity in the leaves of transgenic tobacco seedlings were significantly higher than that of wildtype tobacco, and the content of malondialdehyde was significantly lower than that of wildtype tobacco. (5) The relative expression levels of LEA and ERF genes in transgenic tobacco were higher than those in wildtype tobacco under drought and drought heat treatments. Studies have shown that the StAN1 gene not only increased the anthocyanin content of plants, but also improved the drought tolerance of plants.

Abstract:To explore the role of calciumdependent protein kinase (CDPK) in the synthesis of yam tuber starch and endogenous hormones, we used Bikeqi yam and Dahechangyu yam as the materials to determine the tuber starch, sugar, endogenous hormone contents and other indicators, as well as did the correlation analysis. The RTPCR (Reverse TranscriptionPolymerase Chain Reaction) technology has been used to clone the open reading frame of calciumdependent protein kinase gene (CDPK20). The bioinformatics analysis and subcellular location were performed. Realtime fluorescent quantitative PCR was applied to analyze the expression of CDPK20 and the correlation analysis of physiological indicators. The results showed that: (1) the open reading frame length of CDPK20 gene is 1 047 bp, encoding a total of 348 amino acids. (2) CDPK20 protein is subcellularly located in the nucleus and cell membrane. (3) The expression of CDPK20 showed a trend of increasing first and then decreasing from 105 d to 165 d after tuber planting. (4) CDPK enzyme activity was extremely significantly positively correlated with starch content, significantly negatively correlated with total soluble sugar and reducing sugar contents, extremely significantly negatively correlated with ABA, and extremely significantly positively correlated with ZR. This result suggests that CDPK is involved in the metabolism of starch and sugar in tubers and the synthesis of plant endogenous hormone ABA and ZR.

Abstract:Blackleg caused by Leptosphaeria biglobosa, is one of the damaging diseases of oilseed rape (Brassica napus). Based on histological observation and RNASeq, we analyzed the phenotypes and gene expression changes of oilseed rape after inoculation with L. biglobosa for 4, 12, 24, 36, 48 and 96 h to discuss the defense response and disease resistance mechanism of oilseed rape in response to the infection of L. biglobosa, provided a theoretical basis for comprehensively revealing the molecular mechanism of interaction between oilseed rape and L. biglobosa, and accumulated genetic information for breeding the disease resistance varieties of oilseed rape. The results showed that: (1) after inoculation for 4-96 h, the leaf spot gradually expanded, and the L. biglobosa formed mycelium within 48-96 h. (2) By RNASeq, a number of 3 384, 2 270, 3 802, 5 811, 6 155, 7 153 differentially expressed genes (DEGs) were obtained at 4, 12, 24, 36, 48 and 96 h of L. biglobosa infection on oilseed rape. (3) qRTPCR results showed that the levels of the 15 differentially expressed genes in oilseed rape were basically consistent with the results of RNASeq. (4) The differentially expressed genes were analyzed by short time series clustering and KEGG enrichment analysis. The results showed that the genes in the pathways of plant and L. biglobosa interaction, protein kinase, jasmonate/ethylene/salicylic acid signaling, and glucosinolate biosynthesis were strongly activated, and their gene expression showed dynamic change trend.

Abstract:MYB transcription factors are one of the largest family of transcription factors in plants, widely involved in plant growth and development, adversity stress, and accumulation of secondary metabolite. Through homology comparison and functional annotation, we screened MYB transcripts in the R. glutinosa transcriptome, and desigend specific primers to amplify MYB gene. Four elicitors including salicylic acid (SA), Ag⁺, methyl jasmonate (MeJA) and putrescine (Put) were further treated on the hairy roots of R. glutinosa, and the expression pattern of the candidate MYB gene were detected by quantitative realtime PCR (qRTPCR). The results showed that: (1) a MYB gene of R. glutinosa was successfully cloned, named RgMYB10. It encodes 247 amino acid residues, the relative molecular mass of the protein was 28.48 kD, and the isoelectric point PI was 5.14, belongs to the R2R3MYB transcription factor. (2) QRTPCR results showed that the expression levels of RgMYB10 was the highest in adventitious roots, followed by stems, and the lowest expression in tuberous roots. (3) The RgMYB10 in hairy roots after MeJA treatment was significantly upregulated, which was a gene specifically responding to MeJA induction. Therefore, we speculate that RgMYB10 gene may be a key transcription factor involved in the biosynthesis of R. glutinosa acteoside in response to MeJA. The results indicate that RgMYB10 may be involved in biosynthesis of R. glutinosa acteoside, which lays the foundation for further research on the function of RgMYB10 in acteoside biosynthesis.

Abstract:In this study, we studied the relationship between Hetian rose variety (Rosa rugosa ‘Hetian shamomeigui’) and Zizhi rose (R. rugosa ‘Zizhi’), Fenghua rose (R. rugosa ‘Fenghua’) and Damask rose (R. damascena) with molecular data, investigated the phylogenetic relationship of the Hetian rose within genus Rosa, and discussed its hybridization origin. Results showed that: (1) the Hetian rose had unique genetic source. The genetic distance within the Hetian rose (0.017±0.003) was smaller than the distance between varieties (0.029±0.005, 0.024±0.004, and 0.022±0.003, respectively). (2) The phylogenetic tree showed that GAPDH gene clones of the Hetian rose did not mix with the gene clones from other varieties. These indicated that the Hetian rose was genetically diverged from the other three roses, and should be regarded as an unique rose variety. (3) A part of GAPDH clones of the Hetian rose were clustered with four species (R. bracteata, R. laevigata, R. cymosa, and R. banksiae) in Rosa sect. Bracteatae, sect Laevigatae, and sect. Banksiae from China or Southeast Asia, located at basal position of the phylogenetic tree, while other GAPDH clones were clustered with other four European species (R. elliptica, R. sempervirens, R. trachyphylla, and R. abyssinica) in sects. Caninae, Synstylae, and Gallicanae. A total of 19 GAPDH heterozygous loci were detected between the Hetian rose and the abovementioned closelyrelated species, indicating a hybrid origin of Hetian rose. (4) A close relationship between the Hetian rose and 14 European species from sect. Caninae, sect. Synstylae, and Gallicanae was revealed by cpDNA phylogeny and sequence variation analysis. In conclusion, it was proposed that the Hetian rose had a hybrid origin by Chinese and European rose species or varieties. The hybrid parents may be the one or more species in sects. Bracteatae, Laevigatae, Banksiae, Caninae, Synstylae, and Gallicanae. This study provides a foundation for further research on the probable parental species of the Hetian rose.

Abstract:In order to reasonable utilize the medicinal plant resources and protect species diversity of Notopterygium incisum and Notopterygium franchetii, this project collected 227 individuals from 23 allpatric and parapatric populations of two Notopterygium species to detect the genetic diversity and species differentiation based on the simple sequence repeats (SSR). The results showed that: (1) N. incisum and N. franchetii had moderate level of genetic diversity. The average number of alleles (N_a), the number of effective alleles (N_e) and the expected heterozygosity (H_e) in N. incisum were 2.603, 1.777, 0.313, respectively. These diversity parameters were higher than that in N. franchetii, the values were 2.200, 1.641, 0.308, respectively. (2) AMOVA showed that the genetic variations were mainly occurred within populations for two Notopterygium species. The divergence index among populations F_st in N. incisum and N. franchetii, were 0.181 and 0.191, respectively. (3) Based on Bayesians structure clustering analysis and principal coordinates analysis, it was concluded that the all sampled individuals have been divided into two genetic clusters, which corresponded to N. incisum and N. franchetii, respectively. The obvious genetic differentiation and few gene exchanges between the two species were identified. These findings suggested that there were higher genetic differentiation among species, and their genetic variations mainly occurred within populations, the two geographic units for N. incisum and N. franchetii should be constructed for further management and conservation.

Abstract:In order to explore and reconstruct the phylogenetic relationships between Hydrangea and its related genera, we selected a total of 61 species from them on a global scale for the phylogenetic analysis based on the nuclear ribosomal internal transcribed spacer (ITS) and three chloroplast DNA fragments (rbcL, trnLF, atpB). Our results suggest that there is little difference between the phylogenetic trees based on the nuclear gene fragment and the chloroplast DNA fragments, respectively. As a result, by further analyzing the phylogenetic tree based on the combined dataset from both of them, two major clades in Hydrangea. We were identified, which were strongly supported by the morphological evidence that is whether the end of the fruit is truncated or not. Moreover, our results suggest that four groups were supported in each major clade and a total of eight groups were identified in Hydrangea. Some groups received strong support from generalized morphological characters. For instance, the first group was supported by morphological characters of leaf shapes, pollen grains and seed coats. Phylogenetic analyses conducted by this study shed new lights on the understanding of relationships among Hydrangea and its related genera.

Abstract:In order to explore relevant information of flavonoid componts and their synthases in Portulaca oleracea L., we utilized both the transcriptome and metabolome to analyze the root, stem and leaf of P. oleracea L. At the same time, 6 differential expressed genes were identified by the RTPCR. The results showed that: (1) by the metabolome, there were 32 flavonoid components included 3 isoflavones, 8 flavonols, 11 flavones, 3 flavanones, 5 flavanols and 2 canthocyanidins in which the contents of 20 flavonoid components were similar, while the other 12 ones were significantly different in root, stem and leaf of P. oleracea L. (2) By the transcriptome, there were 93 flavonoid synthases which included 20 CHSs, 3 CHIs, 7 F3Hs, 2 ANSs, 11 IFSs, 21 F3′Hs, 2 F3′5′Hs, 2 DFRs, 2 ANRs, 1 LAR and 22 UF3GTs in root, stem and leaf of P. oleracea L. (3) According to the result of transcriptome, the expressed trend of these 6 flavonoid synthases agreed with the testing by the RTPCR. However, the trend multiples of these differentially expressed genes by these 2 kinds of approaches were different. So this study concluded that there are many flavonoid components and their synthases in P. oleracea L. including root, stem and leaf, but the contents of flavonoids and the expression of their enzymes in different tissues are distinct.

Abstract:In order to overcome the phenomenon of pistil abortion in apricot production and improve the fruit setting rate, we used the flower buds of fruiting branches of ‘Liguangxing’(Prunus armeniaca L. var. glabra Sun S. X.) with different tree vigor (strong tree, moderate tree and weak tree) and different types (bunch shaped fruit branch, short fruit branch, middle fruit branch and long fruit branch) in full fruit period as materials to investigate the flowering phenology and biological characteristics. Paraffin sections were used to observe the morphology of the internal tissue structure of flower buds in the abortion prone period (flower bud differentiation stage, pistil differentiation stage, pollen cell stage and flower bud expansion stage). At the same time, the changes of soluble sugar, starch contents and mineral elements in leaves at different main abortion stages were determined. The results showed that: (1) the average abortion rate of flower bud of weak tree was the highest (91.26%), and that of median tree was the lowest (71.08%). For different types of fruiting branches, the abortion rate of flower bud of flower bundle like fruit branch was the lowest, and that of long fruit branch was the highest. (2) The size of pollen viability was as follows: cluster branches > short branches > medium branches > long branches, and the germination rate was as follows: short branches > cluster branches > medium branches > long branches. The pollen viability of flower type was as follows: pistil is higher than stamen > pistils as long as stamens > pistil is lower than stamen > no pistil, and the germination rate was as follows: pistils as long as stamens > pistil is higher than stamen> pistil is lower than stamen > no pistil. (3) The contents of soluble sugar and starch in leaves at pistil differentiation stage were significantly lower than those at other stages; the contents of P, K and Ca in leaves were higher at early differentiation stage, but decreased significantly at pistil and stamen differentiation stage. (4) Compared with the normal flowers, the abortive flowers mainly showed abnormal ovary development, uneven growth points, atrophy of ovary and stagnation of ovule primordium development. The style of pistil of abortive flower was lower than that of filament, and the number of pollen grains decreased sharply. The results showed that the pistil abortion was serious and the fruit setting rate was very low. The difference of the proportion of abortive flowers was caused by the strength of trees. Whether the pistil development is normal or not is directly related to the normal flowering of ‘Liguangxing’. The development of pistil is blocked and eventually becomes the main form of flower bud degeneration. Leaf carbohydrate and mineral elements and other nutrients participate in and ensure the normal development of flower organs.

Abstract:In order to determine the chemical composition of Artemisia anethoides Mattf. essential oil, and explore its antibacterial activity and antibacterial mechanism, we extracted the essential oil of Artemisia anethoides Mattf. by the steam distillation, and its chemical constituents were determined by gaschromatographymass spectrum (GCMS) in this study. The antibacterial activity of the essential oil was determined by the inhibition zone method, double dilution method and growth curve method, and the antibacterial mechanism of the essential oil was investigated by the electrical conductivity method and scanning electron microscope method. The results showed that: (1) the main chemical constituents of Artemisia anethoides Mattf. essential oil included alcohols (47.12%) and terpenes (19.90%), among all the components, the content of eucalyptol (12.39%) was the highest, followed by terpineol (8.70%). (2) The diameters of inhibition zone of essential oil against S.aureus and E.coli were (22.57±1.68) mm and (15.36±0.71) mm, respectively. (3) The minimum inhibitory concentrations of essential oil against S. aureus and E. coli were 3.25 and 7.5 μL/mL, respectively, and the minimum bactericidal concentrations were 7.5 and 15 μL/mL, respectively. (4) When the concentration of essential oil were 1.625 and 3.25 μL/mL, it could delay the growth of both S.aureus and E. coli. When the concentrations of essential oil were 3.25 and 7.5 μL/mL, it could inhibit the growth of S. aureus completely, and when the concentrations of essential oil were 7.5 and 15 μL/mL, it could inhibit the growth of E. coli completely. (5) Having been treated with essential oil, the relative conductivity of the bacteria increased significantly, with the increased of the essential oil concentration. In addition, the phenomenon of atrophy and rupture of the cell membrane occurred. The study found that the essential oil of Artemisia anethoides Mattf. was rich in many active substances, such as alcohols and terpenes. It had good antibacterial activity against S.aureus and E.coli, and the essential oil of Artemisia anethoides Mattf. could change the membrane structure of cells and resulted in the leakage of soluble substances in bacteria, thereby inhibit the growth of bacteria.

Abstract:The symbiosis of Armillaria spp. and Gastrodia elata is an interaction consequence of the infection system of Amillaria spp. and the digestive and/or antifungi system of G. elata, and this may be regulated by temperature. In order to reveal the influence of altitude on the yield and quality of Gastrodia spp., and the mechanism how increased temperature damage the symbiosis of Armillaria biological species and G. elata, this study determined the yield of G. elata cultivated at different altitudes, and the contents of the main medicinal components gastrodin and phydroxybenzyl alcohol. The symbionts of G. elata were heated up in the room, then activity of chitinase, β1, 3glucanase, phenylalanine ammonia enzyme and polyphenol oxidase were determined, as well as the inhibition effects of homogenate of the G. elata tube on Armillaria mycelial growth. Results showed that： (1) altitude had a significant effect on the yield and effective medicinal components of hybrid of G. elata B1. f. elata × G. elata B1. f. glauca, with the highest yield at 1 600 m and the highest content of effective components at 1 600 m. (2) Temperature significantly affected the antifungal system of G. elata, and the response of G. elata digestive enzymes and defense enzyme systems to temperature is different. The specific manifestation is that the digestive enzyme system activity of G. elata increases under low temperature conditions and the activity of defense enzyme system at high temperature. (3) The increase in temperature leads to a significant decrease in the inhibitory effect of G. elata tissue fluid on the mycelium of Armillaria. There may be heatinactivating factors in living G. elata that promote the growth of Armillaria. Studies have shown that the increase in temperature caused by the decrease in altitude in Gastrodia planting areas may weaken the ability of G. elata to digest and inhibit Armillaria, thereby destroy the symbiosis balance between G. elata and Armillaria. This research has important scientific value for revealing the symbiosis mechanism of ArmillariaGastrodia elata, and has practical significance for the zoning of G. elata cultivation.

Abstract:In order to explore the photosynthetic physiological characteristics of different trees, shrubs, herbs in Helan Mountain and their adaptive characteristics and mechanisms to the natural environment, we used a Li6400XT portable photosynthesis instrument to determine the gas exchange parameters and natural environmental factors of ten types of trees, shrubs and herbs in Helan Mountain and analyzed their correlations. The results show that: (1) the daily mean value of net photosynthetic rate (P_n) changed in a rank of Thermopsis lanceolata>Ulmus glaucescens>Populus davidiana>Cotoneaster hissaricus>Agropyron cristatum>Pinus tabuliformis>Lonicera microphylla>Berberis thunbergii>Picea crassifolia>Carex muliensis, and from the perspective of different life types, it was represented as tree > herb > shrub. (2) The diurnal variation curves of P_n of P. crassifolia, P. tabuliformis, U. glaucescens, B. thunbergii, C. hissaricus and L. microphylla were single peaks, while the Pn diurnal curves of P. davidiana, T. lanceolata, C. muliensis and A. cristatum were double peak shape, with obvious photosynthetic “noon break” phenomenon. The phenomenon of P. davidiana and A. cristatum were mainly caused by nonstomatal factors, while T. lanceolata and C. muliensis were mainly caused by stomatal factors. (3) Compared with other plants of the same life type, P. crassifolia, P. tabuliformis, L. microphylla and T. lanceolata had higher daily mean water use efficiency (WUE). (4) Path analysis showed that light intensity (PAR) was the main determinant factor for trees and shrubs, while leaf temperature (T_l) and saturated vapor pressure deficit (VPD) were the main limiting factors.The main limiting factors for herbaceous plants were air temperature (T_a) and T_l. The study suggested that diurnal variations of photosynthetic characteristics of different arborshrubgrass in Helan Mountain show different patterns. Compared with other plants of the same life type, P. crassifolia, P. tabuliformis, L. microphylla and T. lanceolata have better drought resistance and can adapt to relatively dry climate environment.

Abstract:Pinus tabuliformis on ridge as one of the typical plant communities plays an important role in biodiversity maintenance and ecological service function achievement. The objective of this study was to understand how leaf functional traits responded to altitudinal gradients. Ten P. tabuliformis on ridge traits were researched with typical sampling method in this study. The results showed that: (1) leaf length(LL), leaf nitrogen content(LNC), leaf phosphorus content(LPC) of 1-3yearold leaf and chlorophyll concentration of 1yearold leaf of P. tabuliformis on ridge were below nonridge. However, the leaf dry matter content(LDMC) and stomata density(SD) of 1yearold leaf of P. tabuliformis on ridge were higher than nonridge. (2) The leaf funcation traits of P. tabuliformis on ridge, including leaf thickness(LT), specific leaf area (SLA) of 1-3yearold leaf, LPC of 1yearold leaf increased linearly with increasing elevation, but LL, LDMC, leaf carbon concentration (LCC), Chl(a+b) of 1-3yearold leaf, SD of 1yearold leaf decreased significantly with increasing elevation. (3) LNC was positively correlated with LPC of 1-3yearold leaf; LDMC negatively correlated with LPC of 1-2yearold leaf; LL was positively correlated with LNC, LPC of 2-3yearold leaf; LKC was positively correlated with LNC, LPC of 2-3yearold leaf. The unique habitat condition of the ridge has created the unique growth strategy of P. tabuliformis. P. tabuliformis on the ridge showed diversified adaptive strategies to adapting varing environmental factors associated with changes in altitude.

Abstract:Fertilization is one of the most common ways of human disturbance in the current grassland ecosystems, which can lead to changes in grassland biodiversity and ecosystem stability. At present, a few studies, however, have explored the effect of fertilization on community stability and the underlying mechanisms, but there are many controversies. For this reason, we took the typical steppe of the Loess Plateau as the research object, and through 8 consecutive years of field experiment of adding nitrogen fertilizer (urea), we studied different nitrogen fertilizer treatments (respectively 0, 5, 10, 20, 40, 80 g·m^-2) influence on the stability of the grassland ecosystem, and tested four underlying mechanisms (species diversity, species synchrony, portfolio effect, dominance) that may affect the stability of community, to clarify the impact of fertilization on community stability and its underlying mechanism thus providing a theoretical basis for the rational use of grassland restoration on the Loess Plateau. The results showed that: (1) as the fertilization level increased, the community stability (S) decreased, and it began to decrease significantly when the fertilization treatment was 20 g·m^-2 (P<0.01). (2) Fertilization significantly reduced the species richness (R) and dominance index (D) (P<0.01). However, the species synchrony (_B) and the meanvariance ratio index (z) did not change significantly (P>0.05). (3) There was a positive correlation between species richness (R) and community stability (S), while dominance index (D) was not correlated with community stability (S). Studies suggested that under the disturbance of fertilization, the decline in species richness of typical steppe on the Loess Plateau led to a decline in community stability, indicating that species diversity plays an important role in maintaining the stability of grassland ecosystem.

Abstract:Distyly is a floral polymorphism, characterized by a reciprocal positioning between stigmas and anthers in different individuals. In this study, we employed Forsythia suspensa to explore divergence in functional gender of two floral morphs and evolutionary significance of the distyly, by determining characteristics of mating system and comparing ovule number, pollen dry weight, pollen viability and longevity between two sexual morphs. The results showed that the species has heteromorphic incompatibility system, with the extremely low fruit set by selfing and intramorphpollination. The ovule number was (26.86 ± 0.37) in the longstyled morph, significantly higher than that in the shortstyled morph. The dry weight of pollen per flower was (0.47 ± 0.02) mg in longstyled morph, significantly lower than (0.60 ± 0.02) mg of the shortstyled one. The content of water in anther was significantly different between two morphs, which in shortstyled was significantly higher than in longstyled. Overall, pollen viability of the shortstyled form was significantly lower than that in the longstyled, so did pollen longevity. In conclusion, it was indicated that the relatively reproductive input in two sexual functions differed between two morphs. The longstyled was femalebiased, realizing its fitness to larger extent by ovules, whereas the shortstyled was malebiased, realizing the fitness largely by exporting pollen.

Abstract:Lilium lankongense is a unique species distributed in the QinghaiTibet Plateau. In order to investigate its karyotype characteristics and the evolution of different populations, we compared and analyzed the karyotypes, which included 8 populations of L. lankongense, by chromosome routine tableting. The results showed that： (1) karyotypes were 3B, and the basic number of chromosome was 12 in the eight populations. The karyotype asymmetry coefficient (As. K%) of eight populations were 81.28% to 83.53%. (2) Combined with previous studies, it is shown that the geographical distribution of L. lankongense populations along the line of ZayüCizhongShangrilaMuli has migration and diffusion from west to east. At the same time, the populations, which distribute in the line from Gongshan to Shangrila, have a geographic expansion of migration and diffusion in northward and southward in latitude. (3) This study found B chromosome in L. lankongense for the first time, and its B chromosome is of great significance for adapting to special habitats. L. lankongense is a highly differentiated species.

Abstract:Based on the light and electron microscopy, we carried out a morphological study on a canalraphebearing diatom species Nagumoea africana from the Yellow Sea, China. Geographical distributions of this species were also herein discussed. The results show that: (1) N. africana frustules are rectangular in girdle view, and the valves are narrowly elliptical with broadly rounded apices. (2) The raphe is located along the valve median line and composed of two branches of equal length. (3) The raphe canal is supported by complex, anastomosing fibulae without a keel. (4) Each stria bears one areola, and a row of areolae may also be present along the mantle. (5) N. africana is now only found in the Saldanha Bay of South Africa and the Yellow Sea of China. This taxa is the first reported species of this genus in China, representing the first record of the genus Nagumoea in China.

Abstract:Sophora moorcroftiana (Benth.) Baker f. albiflora S. H. Yang, a new form of Leguminosae from China is described. It is distinct from the typical form, S. moorcroftiana (Benth.) Baker, by having white petals, which is quite stable. At the same time it is randomly distributed in typical form populations.

Abstract:Trichomes are derived from the extension of plant epidermal cells and are a unique structure. trichomes can be divided into glandular and nonglandular trichomes. Glandular trichomes are secretory trichomes where a large number of secondary metabolites are synthesized, stored and released. Glandular trichomes often secrete different types of defensive substances such as terpenes, amino acids and phenylpropanes, acylsugars, fatty derivatives, etc. These secondary metabolites can protect plants from biotic and abiotic stresses and have important defensive effects. Therefore, this article summarizes the types of glandular trichomes, the synthesis and regulation of defense substances, and focuses on the study of its synthesis pathways, regulation mechanisms and transport mechanisms to provide references for the research on the biosynthesis and genetic improvement of defense substances.

Abstract:Spatial variation patterns of species biodiversity and biomass, together with the response of their correlation to increasing temperature under global warming conditions, are hot topics in ecological researches. Such patterns are also the keys to explore the response process of community stability to global warming. Species distribution was produced by interaction of multiple ecological processes. Temperature increment affected species diversity by modifying the function of key species in communities, and thus altered the community stability. As for the response process of grassland community stability to global warming, many scholars have conducted researches, but their conclusions have revealed large discrepancies. In the present work, species biodiversity and biomass were reviewed from their spatial variation pattern, response to rising temperature, and interactive correlation, combined with our own research results from the QinghaiTibetan Plateau and the Loess Plateau. Key research directions were then proposed in the study of the response of grassland community stability to global warming.