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    20 January 2024, Volume 44 Issue 1
    Review
    Recent Advances on Plant Root Thermomorphogenesis
    Wei LIU, Ziqiang ZHU
    2024, 44(1):  1-7.  doi:10.7525/j.issn.1673-5102.2024.01.001
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    Plant development is highly plastic. As ambient temperature increased, plant stems and petioles elongated, and promoted leaf surface cooling, the process known as thermomorphogenesis. High temperatures also triggered root elongation, which named as root thermomorphogenesis. There were many studies on the regulation of plant shoot thermomorphogenesis, but few investigations on the regulatory mechanisms of plant root thermomorphogenesis. In this review, we summarized the recent progresses in the field of plant root thermomorphogenesis, and proposed future research directions.

    Taxonomy
    Rubus chrysobotrys var. glandulosus(Rosaceae), a New Variety from Sichuan
    Haiyan BI, Yun LIN
    2024, 44(1):  8-11.  doi:10.7525/j.issn.1673-5102.2024.01.002
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    A variety of Rubus chrysobotrys Hand.-Mazz.(Rosaceae), Rubus chrysobotrys Hand.-Mazz. var. glandulosus L.T.Lu, was described as new from southern Sichuan, China. The diagnostic differences between this new variety and Rubus chrysobotrys Hand.-Mazz. var. chrysobotrys and the key to varieties of Rubus chrysobotrys Hand.-Mazz. were given, and photos of vouchers were provided.

    Eight Newly Recorded Species of Spermatophyte from Gexigou National Nature Reserve,Sichuan Province
    Xuyan CHEN, Xingyu LIU, Mei HUANG, Ting DENG, Xiaolu GONG, Zhimin JIANG, Gang GAO
    2024, 44(1):  12-16.  doi:10.7525/j.issn.1673-5102.2024.01.003
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    Based on field investigation and specimen identification in Gexigou National Nature Reserve, six families, seven genera, six species, one subspecies and one variety were identified as new records in Sichuan Province, viz. Populus wuana C. Wang et Tung(Salicaceae), Lonicera spinosa Jacq. ex Walp.(Caprifoliaceae), Rhododendron przewalskii Maxim.subsp. yushuense Fang et S.X.Wang(Ericaceae), Ligularia confertiflora Chang(Asteraceae), Rhodiola serrata H. Ohba(Crassulaceae), Meconopsis racemosa var. spinulifera(L.H.Zhou) C.Y.Wu et H.Chuang(Papaveraceae), Taraxacum luridum Hagl.(Asteraceae), Taraxacum pseudoatratum Oraz.(Asteraceae), voucher specimens(GAO20230301-08) were preserved in the herbarium of Yibin University.

    Systematic and Evolutionary
    Prediction of Suitable Distribution Area of Corydalis trachycarpa (Papaveraceae) in China under Climate Change
    Qian YANG, Yuan YUAN, Xu SU, Yuping LIU, Dong WANG, Xiaoli LI, Chenglin SUN, Ping YANG
    2024, 44(1):  17-26.  doi:10.7525/j.issn.1673-5102.2024.01.004
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    In order to explore the potential suitable distribution area and the suitable living environment of Corydalis trachycarpa, and to provide a theoretical basis for resource utilization and protection of C. trachycarpa. Based on the existing distribution sites, climatic variables, and environmental variables of C. trachycarpa, MaxEnt modeling and ArcGIS software were used to simulate the potential distribution of C. trachycarpa in China for four periods under current climate condition(1970-2000) and Shared Socioeconomic Pathway(SSP) 245 scenario model(2021-2040, 2041-2060, 2061-2080, 2081-2100), and environmental factors limiting its distribution were analyzed. The results showed that the most important environmental factors determining C. trachycarpa distribution were altitude(Alt, contribution rate was 60.9%), standard deviation of temperature seasonality(bio4, contribution rate was 11.1%), precipitation during the warmest quarter(bio18, contribution rate was 9.4%), and the precipitation variation coefficient(bio15, contribution rate was 7.0%). The cumulative contribution of these four factors was 88.4%. Under current climate conditions, the MaxEnt model predicted a total potential distribution area of approximately 1.7494×106 km2 for C. trachycarpa, primarily distributed in northwest Sichuan, southern Gansu, eastern Xizang, northwest Yunnan, and Qinghai within the eastern Tibetan Plateau. Compared with the current climate conditions the most, moderate and low suitable areas of C. trachycarpa under SSP 245 scenario might increase in the next four periods, showing a trend of expansion toward Yunnan, eastern Xizang, and other lower latitude regions.

    Sporogenesis and Gametogenesis of Messerschmidia sibirica L.(Boraginaceae) and Their Taxonomic Implications
    Haobo SUN, Dongrui KONG, Dechang HU
    2024, 44(1):  27-33.  doi:10.7525/j.issn.1673-5102.2024.01.005
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    The systematic position of Messerschmidia L. has been problematic which was ever moved into Tournefortia L. or Heliotropium L. Sporogenesis and gametogenesis in Messerschmidia sibirica were observed using conventional paraffin sectioning and light microscopy to provide embryological data for a better understanding of the systematic position of Messerschmidia. The results were as follows: (1)The anther was tetra-sporangiate, the primarily matured anther wall comprised four layers: the epidermis, endothecium, a middle layer and tapetum, the development of the anther wall was of the Dicotyledonous type, the tapetum with two-nucleate cells was secretary, the epidermis was persistent and the endothecium was irregularly 2- layered with fibrous thickening; (2)Microsporocyte undergone a meiotic division with a simultaneous cytokinesis resulting in a tetrahedral microspore tetrad, the mature pollen grains were 2-celled; (3)The ovule was unitegmic, anatropous and crassinucellate with a long thin micropyle and weak integument tapetum, some of the nucellar tissue was persistent at the stage of mature embryo sac; (4)The development of the embryo sac was of a Polygonum type, the shape of the mature embryo sac was fusiform with polar nuclei fused before fertilization and antipodal cells already degenerated. The embryological characters of Messerschmidia sibirica might be very similar to those of Heliotropium. Considering the stability of embryological characters within genus, the results suggested that it might be suitable to classify Messerschmidia into Heliotropium based on the molecular phylogenies.

    Phyto-community Characteristics of the Dependent Environment of Dipteris shenzhenensis
    Yuqi MA, Yuhui LI, Lin LIN, Yue SHEN, Yufeng GU, Faguo WANG
    2024, 44(1):  34-44.  doi:10.7525/j.issn.1673-5102.2024.01.006
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    Dipteris shenzhenensis is a critically endangered(CR) plant distributed only in Shenzhen. The phyto-community analysis of this dominant community was studied and analyzed, and the results showed that: there were 85 species, 73 genera and 49 families of vascular plants in Dipteris shenzhenensis community, the dominant species included Gordonia axillaris, Ilex memecylifolia, Cyclobalanopsis neglecta, Enkianthus quinqueflorus, Litsea rotundifolia var. oblongifolia, Dipteris shenzhenensis, Dicranopteris pedataPlant individuals in this community decreased with the increase of tree height, showing an “Inverted J” type distribution, which was an obvious characteristic in subtropical areas. The diversity and evenness index of all life forms showed a trend of “high in the middle and low in the two ends”; The T test of the species diversity index of different communities in the same area proved that there was no significant difference in diversity level between different communities, which belonged to the stable stage of ecological succession; Niche analysis revealed the survival status of Dipteris shenzhenensis in the community, indicating that this species was not widespread, demanding for environment and poor competitiveness in resources, and there was a risk of extinction during community succession; Interspecific association analysis revealed the interspecific relationship between this species and other dominant herbs, and identified possible complementary and competitive plants.

    Effects of Multi-walled Carbon Nanotubes on Gametophyte Development and Sporophyte Production of Ceratopteris thalictroides
    Yandong GUO, Yifeng ZHOU, Yuhong ZHENG, Mingxia ZHANG, Enhui LIAO, Jianguo CAO
    2024, 44(1):  45-50.  doi:10.7525/j.issn.1673-5102.2024.01.007
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    To explore the effects of multi-walled carbon nanotubes in gametophyte development and sporophyte production of Ceratopteris thalictroides, and to lay a foundation for conservation and breeding of endangered ferns.C. thalictroides was used as material, and five treatment group of 0(the control), 0.5, 1.0, 2.5, 5.0 mg·L-1 was set,and the effects of different mass concentrations of multi-walled carbon nanotubes on gametophyte development and sporophyte formation of C. thalictroides were observed by light microscope. The results showed that compared with the control group, 0.5-2.5 mg·L-1 multi-walled carbon nanotube treatment could advance spore germination by about 15 d, among them, 0.5 mg·L-1 multi-walled carbon nanotubes had the best effect on spore germination, 0.5-1.5 mg·L-1 multi-walled carbon nanotubes had the best effect on protonema and plate formation, and 2.5 mg·L-1 multi-walled carbon nanotubes had the best effect on prothallus and sporophyte formation. High mass concentration (5.0 mg·L-1) of multi-walled carbon nanotubes led to deformity of some gametophytes, and spermogonium degradation, chlorosis of chloroplasts in cells, and chlorosis of chloroplasts in some cells on the developing sporophytes cells. In addition, male gametophytes was promoted by the addition of multi-walled carbon nanotube. In conclusion,0.5-2.5 mg·L-1 multi-walled carbon nanotube treatment might significantly promote gametophyte development and sporophyte production of C. thalictroides, and the number of spermogonium increased significantly, and both monoecious and dioecious gametophytes appeared simultaneously, high mass concentration of multi-walled carbon nanotube treatment might result in‘high concentration inhibition’ of gametophyte development of C. thalictroides. In the process of practical application, the corresponding addition amount should be selected based on the specific need.

    Genetic and Breeding
    Phenotype and Pigment Analysis of Flower Organs of Iris lactea var. chinensis
    Nan LI, Xiaoxia TIAN, Peichun MAO, Mingli ZHENG, LIN MENG, Lan YUN
    2024, 44(1):  51-61.  doi:10.7525/j.issn.1673-5102.2024.01.008
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    To analyze the phenotypic traits of the floral organs of Iris lactea var. chinensis germplasm resources and to clarify the pigment composition of the petals, 22 I. lactea germplasm resources under different habitat conditions in six provinces and cities of China were used as experimental materials to systematically study the phenotypic characteristics and anthocyanin of this important ornamental part of flower organs. The phenotypic traits of the floral organs were described by RHSCC colorimetry and colorimeter colorimetry, and the mass fraction of floral pigment was determined by sodium nitrite-aluminum nitrate colorimetry and pH differential analysis, and the differences in the expression of floral pigments in different color lines were analyzed. The results showed that the flower color of 22 germplasm resources could be divided into four color families: light blue, light blue-violet, dark blue-violet and violet. The brightness(L*) of the fall and standard petals was negatively correlated with a*, positively correlated with b*, and negatively correlated with color(c*) respectively. Among the four color families, violet petals were the largest, flower branch length was the highest, and fall spot was the smallest. While light blue petals were the smallest, flower branch length was the lowest, and fall spot was the largest. It indicated that the darker the petal color, the larger the petal, and the smaller the fall spot. The mass fraction of pigment in the petals of different colors of I. lactea differed significantly. The mass fraction of carotenoid in the light blue petals was significantly higher than that in the violet color, while the mass fraction of flavonoid and anthocyanin in the violet petals were significantly higher than that in the light blue color. As the petal color deepened, the mass fraction of carotenoid decreased and the mass fraction of flavonoid and anthocyanin increased correspondingly. The correlation analysis revealed that the mass fraction of carotenoid was significantly positively correlated with fall and standard petal L*(P<0.05), and significantly negatively correlated with fall and standard petal a* and c*(P<0.05).The mass fraction of flavonoid was highly significantly negatively correlated(P<0.01) with fall and standard petal L* and b*, highly significantly positively correlated(P<0.01) with fall and standard petal a*, significantly positively correlated(P<0.05) with fall and standard petal c*. The correlation results between the mass fraction of anthocyanin and colorimetric parameters were similar to those of flavonoids, indicating that the mass fraction of flavonoids and anthocyanins played an important role in the coloration of I. lactea.

    Physiology and Ecology
    Effects of Pectinase on the Distribution of Arabinogalactan Proteins in Developing Fruit of Ziziphus jujuba ‘Lingwu Changzao’
    Jing WANG, Yingcai ZHANG, Shanshan TAO, Xue YANG
    2024, 44(1):  62-74.  doi:10.7525/j.issn.1673-5102.2024.01.009
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    To explore the effects of pectinase on distribution of arabinogalactan proteins(AGPs) in fruits at different developmental stages,and to provide anatomical evidence for revealing the effects of pectinase on fruit ripening and softening, the fruits of Ziziphus jujuba ‘Lingwu Changzao’ at four different development stages were treated with three different concentrations pectinase, and AGPs epitopes analysis in situ at cellular level of fruits was performed using immunocytochemistry technique. The results showed that the fluorescence intensity of the antigens recognized by JIM13 and JIM8 and MAC204 antibodies was varied in different tissues during the development of fruit at each stage. When fruit tissues were treated with 0.028 U·mL-1(E1) pectinase, there were no obvious changes in pericarp tissue structure, AGPs antigen epitopes in cell wall surface and intercellular space of pericarp and interior parenchyma cells decreased. When fruit tissues were treated with 0.056 U·mL-1(E2) and 0.084 U·mL-1(E3)pectinase, disintegration degree of cell wall in fruit tissue increased, the amount of AGPs epitopes detected in cell wall of pericarp and inner parenchyma cells decreased gradually, an increase in pectinase concentration resulted in a greater effect of AGPs on the arrangement of all epitopes in fruit and a lower fluorescence signal. After treatment with pectinase concentration up to 0.084 U·mL-1(E3), Calcofluor White staining revealed fluorescence attenuation or reduction to varying degrees in the cell wall region, disturbance of AGPs distribution and absence of antigen epitopes were associated with changes of cellulose assembly in cells. The results indicated that the distribution of AGPs carbohydrates differed in fruits at different stages, which was related to changes in tissue structure. The absence of AGPs glycan chains in the presence of pectinase led to the block of the establishment of correlations between cell wall components and cell wall structure remodeling, and the changes in the whole cell wall structures were induced and fruit ripening was affected.

    Population Structure and Dynamic Characteristics of the Endangered Plant Chunia bucklandioides in Diaoluo Mountain of Hainan
    Huiying GUI, Fazhi FANG, Zhaojia LI, Youzhuan MAI, Xiaofeng ZHANG
    2024, 44(1):  75-85.  doi:10.7525/j.issn.1673-5102.2024.01.010
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    In order to explore the population structure and dynamic characteristics of Chunia bucklandioides in Diaoluo Mountain of Hainan, the local wild population of C. bucklandioides was taken as materials, and the concentrated distribution area of the population was set as a typical sample plot to survey, and construction of population age structure instead of space for time was designed. The current population structure and dynamic characteristics were analyzed by the dynamic quantitative analysis, survival curve drawing and survival function calculating, and the future development trend of C. bucklandioides was speculated by time sequence prediction model. The results showed that: (1)The age structure of C. bucklandioides population in Diaoluo Mountain was close to an irregular pyramid type. Dynamic quantitative analysis showed that the population was a growing population, but there was a decline trend from the age class Ⅰ to Ⅲ. The population had weak growth, poor stability, high sensitivity to external interference, and a trend towards a stable population. (2)With the increase of age class, the number of standardized survival individuals decreased, the life expectancy decreased, and the mortality and vanish rate showed an upward trend. The survival curve tended to be Deevey-Ⅱ type. (3)Survival analysis showed that the population of C. bucklandioides in Diaoluo Mountain increased in the early stage, stabilized in the middle stage, and declined in the late stage. (4) After two, four and six age classes in the future, there would be a gradually decreasing trend from I to Ⅲ age class, and slightly increasing trend from Ⅳ to Ⅶ age class. The self-renewal ability of young seedlings was insufficient, and there was a risk of population shrinkage and decline. Consequently, habitat fragmentation, small distribution range, low seed yield and insufficient young individuals might be the main factors leading to the endangerment of C. bucklandioides in Diaoluo Mountain. The results suggested to promote the rejuvenation and renewal of C. bucklandioides population by setting up small nature reserve, assisting seed germination, accelerating artificial cultivation technology research, artificially expanding population size and quantity, and strengthening basic research.

    Effects of Nitrogen Addition on Root Growth, Biomass Allocation and Non-structural Carbohydrate Content of Cinnamomum bodinier Seedlings in Rare Earth Tailings
    Zhiqi CHEN, Haina ZHANG, Jiali LIU, Xianghui LU, Baocheng YANG
    2024, 44(1):  86-95.  doi:10.7525/j.issn.1673-5102.2024.01.011
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    In order to explore the effects of nitrogen addition on the growth and non-structural carbohydrate(NSC) content of Cinnamomum bodinieri seedlings in rare earth mine tailings, one-year-old C.bodinieri cuttings were used as materials, and calcium ammonium nitrate was used as nitrogen fertilizer(containing N 15%), and three nitrogen levels(CK(0), N1(1.8 g per plant), N2(3.6 g per plant)) were set up to analyze the differences in root growth, biomass distribution and NSC of C.bodinieri seedlings under three nitrogen addition levels, and to explore the response of C.bodinieri in rare earth tailings to nitrogen addition. The results showed that: Nitrogen addition increased the biomass accumulation of different tissues of C.bodinieri seedlings in rare earth tailings, and the leaf biomass and canopy biomass at N1 level were significantly increased by 44.75% and 57.43%(P<0.05), respectively, compared with N2. Compared with CK and N1 treatment, the leaf mass ratio of N2 level was significantly increased by 123.53% and 15.85%(P<0.05), respectively. Nitrogen addition significantly promoted the root length and root surface area of both coarse roots(diameter>2mm) and fine roots(diameter≤2mm)(P<0.05), and the promotion effect of N1 treatment was the most significant(P<0.05). The specific root length and specific surface area under N2 treatment were higher than those of CK and N1, and significantly different from CK(P<0.05). For NSC, N1 treatment increased the soluble sugar mass fraction in leaves and stems, while the NSC mass fraction of fine roots under N2 treatment was significantly lower than that of CK and N1 by 46.49% and 28.61%, respectively. In summary, during vegetation restoration in rare earth mine tailings, 1.8 g per plant calcium ammonium nitrate fertilizer might be suitable for fertilization management of C.bodinieri seedlings.

    Comparative Analysis of Growth, Photosynthetic Physiology and Root Tip Ion Flow Characteristics of Five Poplar Varieties
    Jing ZHANG, Weixi ZHANG, Changjun DING, Zhengsai YUAN, Lirui DAI, Xiaohua SU, Yingbai SHEN, Guanzheng QU
    2024, 44(1):  96-106.  doi:10.7525/j.issn.1673-5102.2024.01.012
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    To provide reference for early selection of fast-growing and adaptable varieties, the difference in growth, photosynthetic physiology, and root tip ion flux were analyzed among in five poplar varieties. The annual seedlings of Populus × euramericana ‘Bofeng 3’, P. × euramericana ‘Bofeng 1’, P. × euramericana ‘Xixiong 1’, P. × euramericana ‘Zhongxiong 7 ’, and P. deltoides × P. suaveolens cl. ‘Zhongxiong 4’ were selected as materials. Growth indexes including plant height and ground diameter were measured at 0 and 30 days under normal culture conditions, respectively. Leaf number, single leaf area, leaf length, leaf width, photosynthetic parameters including PnCiGsTr, SPAD and K+, Ca2+, H+ ion flux of roots were measured at 10, 20 and 30 days, respectively. Under 30 days normal management, There were significant differences in plant height growth among the five varieties, from high to low, it was ‘Zhongxiong 4’, ‘Xixiong 1’, ‘Bofeng 3’, ‘Zhongxiong 7’ and ‘Bofeng 1’. Among them, the photosynthetic characteristics and transpiration rate of ‘Bofeng 1’ were the largest, and those of ‘Zhongxiong 4’ were the smallest. However, the single leaf area((57.49±2.37) cm2), total leaf area((1 721.10±28.59) cm2), net photosynthetic rate ((17 863.10± 910.21) μmol·m-2·s-1) and water utilization rate((3.15±0.06)μmol·mmol-1) of ‘Zhongxiong 4’ were significantly decreased. were the largest. The efflux velocity of K+ was the slowest((62.68±0.45) pmol·cm-2·g-1), and the influx velocity of Ca2+ was the fastest((-74.24±1.29) pmol·cm-2·g-1). The net photosynthetic rate ((8 539.70±164.64) μmol·m-2·s-1) and water utilization rate((2.64±0.07) μmol·mmol-1) of ‘Bofeng 1’ were the lowest, and the outflow velocity of K+ was(130.81±1.71) pmol·cm-2·g-1. The Ca2+ influx velocity((-34.43±0.84) pmol·cm-2·g-1) was the slowest. In summary, among the five varieties, ‘Zhongxiong 4’ might have potential strong environmental adaptability, with the highest total leaf area, Pnand WUE, the lowest Tr the smallest K+ efflux, largest Ca2+ influx of and most active H+ of root tip, and best plant height growth performance, which might be suitable for planting a wider range.

    Physiological Responses of Three Bryophytes to Simulated Atmospheric Nitrogen Deposition
    Boyi SONG, Mingming WANG, Weiwei ZHUANG
    2024, 44(1):  107-117.  doi:10.7525/j.issn.1673-5102.2024.01.013
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    Bryophyte is an important component of the surface ecosystem. The physiological response of bryophyte(Syntrichia caninervisBryum argenteum and Plagiomnium acutum) to nitrogen deposition could provide insights into how to use bryophyte scientifically and rationally to indicate the atmospheric nitrogen deposition. Three bryophytes in the northwest of China were selected as materials, and four different nitrogen treatment concentrations(0(N0), 2(N2), 4(N4), 6(N6) g·m-2) were set up, the physiological responses of three bryophytes to the above nitrogen concentration gradients were indicated by measuring the contents of chlorophyll, osmotic regulators and antioxidant enzyme activities. The results showed that:(1)P. acutum of chlorophyll a and chlorophyll b was promoted by 4 nitrogen treatments, especially by N4 treatment. However, N2 had significant inhibitory effects on chlorophyll a and chlorophyll b of B. argenteum and S. caninervis. (2)Proline(Pro), soluble sugar(SS) and soluble protein(SP) were produced in bryophytes to regulate cell osmotic balance. The contents of Pro, SS and SP in B. argenteum and P. acutum all increased under different nitrogen concentrations, but the contents of Pro, SS and SP in mosses decreased under low nitrogen treatment, indicating S. caninervis were more sensitive to N. (3)under the given nitrogen addition treatment, the antioxidant enzyme activities of three bryophytes were promoted by low concentration of nitrogen, but inhibited by high concentration of nitrogen. (4)SOD and CAT played major role in the regulation of the antioxidant system in S. caninervisB. argenteum and P. acutum, respectively. In conclusion, S. caninervis was the most sensitive to nitrogen increase of the three bryophytes, followed by P. acutum. And B. argenteum, suggesting that S. caninervis could be used as an indicator plant for atmospheric nitrogen deposition.

    Nitric Oxide Mediates Brassinosteroids-induced Chilling Tolerance in Chorispora bungeana Suspension Cultured Cells
    Yajie LIU, Lizhe AN
    2024, 44(1):  118-131.  doi:10.7525/j.issn.1673-5102.2024.01.014
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    In order to investigate whether brassinosteroids(BRs)-induced chilling tolerance is regulated through nitric oxide(NO) signaling molecule, the suspension cultured cells of Chorispora bungeana were treated with 24-epibrassinolide(EBR), NO donor SNP, NO scavenger PTIO, nitric oxide synthase(NOS) inhibitor L-NAME, EBR+PTIO and EBR+L-NAME respectively, and the effects of the above treatments on chilling tolerance, reactive oxygen species(ROS) levels and antioxidant defense system were analyzed in the cells under low temperature stress. The results showed that: (1)exogenous EBR treatment enhanced chilling tolerance in the suspension cultures and alleviated the inhibition of cell viability and aggravations of ion leakage and membrane lipid peroxidation induced by low temperature. The effects of SNP treatment on the above physiological measures were similar to those of EBR. (2)Application of PTIO or L-NAME in combination with EBR significantly decreased cell viability and increased ion leakage and membrane lipid peroxidation in C. bungeana suspension cultures under chilling stress compared with those of EBR treatment alone, suggesting that the block in NO signaling decreased the EBR-enhanced chilling tolerance. (3)EBR treatment further increased NO production and NOS activity in the suspension cells compared with those under chilling stress alone, whereas the EBR-induced NO signal was quenched by the addition of PTIO or L-NAME. (4)Both EBR and SNP obviously inhibited the increases in hydrogen peroxide(H2O2) content, superoxide radical(O2·) production rate and hydroxyl radical (OH-content caused by chilling, and remarkably enhanced the activities of ascorbate peroxidase(APX), catalase(CAT), glutathione reductase(GR), peroxidase(POD) and superoxide dismutase(SOD) and contents of ascorbate (AsA) and glutathione(GSH) in the suspension cultured cells, thus alleviating oxidative injury caused by low temperature. However, PTIO and L-NAME blocked the protective effects of EBR. In conclusion, these results suggested that EBR-induced chilling tolerance in C. bungeana suspension cultured cells was through the promotion of NO accumulation by activating NOS activity. EBR might confer an increased tolerance to chilling stress by suppressing the accumulation of ROS caused by chilling and enhancing antioxidant defense system in the suspension cells, both of which were partially regulated by NO signal, resulting in the alleviation of chilling-induced oxidative damage and membrane lipid peroxidation. Thus, NOS-derived NO might be a downstream signaling molecule of EBR signal in C. bungeana suspension cultured cells under low temperature stress.

    Molecular biology
    Construction and Identification of TRV-mediated VIGS Transformation System of Iris sanguinea
    Guiling LIU, Nuo XU, Gongfa SHI, Ling WANG
    2024, 44(1):  132-138.  doi:10.7525/j.issn.1673-5102.2024.01.015
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    To analyze gene function in plants lacking stable genetic transformation system, virus-induced gene silencing(VIGS) was needed, and Iris sanguinea, a monocotyledon, was selected as materials. The specific fragment of IsPDS gene was isolated and the VIGS recombinant vector pTRV2-IsPDS was constructed and leaves were infected by injection. The results showed that the most effective infection was achieved by injecting its leaf veins with syringes when the OD600 values of the resuspension were adjusted to 0.8-1.0 after the those of pTRV1 and pTRV2-IsPDS were adjusted to 1.8-2.0. The experiment was conducted when outdoors temperature was 15-20 ℃ from 6 p.m. to 8 p.m., and a 1 mL syringe needle pricking the outer epidermis of I. sanguinea leaves and 1 mL of heavy suspension slowly injected along parallel veins into its vascular bundles. A clear albino phenotype might appear after about 14 days. TRV1 and TRV2 virus vectors were detected in the plants with phenotypic changes and in the no-load group. The expression of IsPDS in the albino plants was significantly lower than that in the no-load group and the control group. With the concentration of agrobacterium tumefaciens carrying virus vector increased in the preparation of infection solution, the infection efficiency of the whole experiment was improved, and no shading was needed after inoculation.

    Bioinformatics Analysis of CbuDELLAs Gene Family and Functional Analysis of CbuGRAS9
    Shanshan WANG, Rui WANG, Erqin FAN, Pengyue FU, Guanzheng QU, Nan WANG
    2024, 44(1):  139-151.  doi:10.7525/j.issn.1673-5102.2024.01.016
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    To provide theoretical basis for genetic improvement of reproductive regulatory traits of Catalpa bungei, DELLAs family genes were identified and the function of CbuGRAS9 was analyzed. Based on the genomic data of Catalpa bungei, five CbuDELLAs genes homologous to Arabidopsis thaliana were identified and cloned. ExPASy, SWISS-MODEL, Plant-mPloc, PlantCare and other online tools were used to predict the isoelectric point, protein structure, sub-cellular localization and promoter cis-acting elements of CbuDELLAs protein. The expression differences of CbuDELLAs were analyzed by using Catalpa ‘Bairihua’ and Catalpa bungei ‘Luoqiu No.1’ as materials, and the molecular function of CbuGRAS9 was confirmed by heterologus transformation in Arabidopsis thaliana, and the proteins interacted with CbuGRAS9 were screened by yeast two-hybrid library. The results showed that the amino acid number of the five CbuDELLAs proteins ranged from 455 to 588 aa, the relative molecular weight of the proteins ranged from 5.04 to 6.43 kDa, and the isoelectric point value ranged from 4.81 to 5.14. All CbuDELLAs proteins contained DELLA and GRAS conserved domains and are hydrophilic proteins. Sub-cellular localization prediction showed that CbuDELLAs protein was located in the nucleus. The analysis of promoter cis-acting elements showed that the five promoter regions of DELLAs all contained cis-acting elements involved in gibberellin reaction. The results of qRT-PCR showed that the expression of CbuDELLAs in Catalpa ‘Bairihua’ were significantly higher than that in Catalpa bungei ‘Luoqiu No.1’, and CbuGRAS9 was the most significantly gene, and the flowering time of CbuGRAS9 transgenic plants were significantly delayed. Proteins interacted with CbuGRAS9 were mainly concentrated in metabolic pathways such as ribosome, amino acid synthesis, secondary metabolism, photosynthesis and TCA cycle.

    Plant reproductive biology
    Flowering Biological Characteristics and Breeding System of Lumnitzera racemosa
    Yanqing CAI, Yujun CHEN, Mei LI, Chuangfa DENG, Liejian HUANG
    2024, 44(1):  152-160.  doi:10.7525/j.issn.1673-5102.2024.01.017
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    In order to reveal the endangered mechanism and carry out related conservation actions of Lumnitzera racemosa, we observed the flowering dynamics of the introduced L. racemosa in Dangan Island Provincial Nature Reserve, Zhuhai, Guangdong, and investigated the breeding system of L. racemosa by using the out-crossing index(OCI), pollen-ovule ratio(P/O), pollen viability and stigma receptivity, and artificial pollination. The results showed that: (1)The flowering period of L. racemosa population started May 16, the full blooming period was from May 25 to July 1, and the last flowering period was from July 5 to August 31, and the flowering period of L. racemosa population was up to 106 days. The flowering duration of inflorescence was 5-18 days, and average duration was (10.80±3.58) days; The single flowering period of L. racemose lasted 7-13 days, with an average of (9.1±1.3) days. (2)Pollen viability was highest on the day of flowering, reaching 58.73%, and decreased on the second day and no longer viable was on the third day; Stigma receptivity was weakest at the first day of opening, then gradually strengthened, and was strongest at 100% at the third day, and maturity time of male and female was inconsistent. (3)OCI was 4, the breeding system of L. racemosa was mainly outcrossing with partial self-compatible, which required pollinator; P/O was 5 740.50±1 318.20, the breeding system was obligate xenogamy; pollination test showed that the breeding system was a mixed mating system with both self and xenogamy. Based on the above, the breeding system of L. racemosa was mainly outcrossing with partial self-compatibility and requiredr pollinators.