Abstract:In this study, the EjAGL6 gene was cloned from the flower buds of ‘Huayuwuhe No.1’ in triploid loquat (Eriobotrya japonica) by gene cloning, and its sequence, subcellular localization and expression level in diploid and triploid loquat cultivars were analyzed. Arabidopsis thaliana was infected by flower dipping method. The expression level of EjAGL6 gene in transgenic A. thaliana plants was analyzed by qRTPCR. The phenotypic differences between wildtype A. thaliana and EjAGL6 transgenic A. thaliana were observed, and the function of EjAGL6 gene was analyzed, providing theoretical basis for analyzing the mechanism of EjAGL6 gene involved in triploid loquat flowering. The results show: (1) Madsbox gene EjAGL6 was obtained successfully. The encoding region (CDS) of EjAGL6 is 732 bp, encoding 243 amino acids. The molecular weight of the putative protein is 27.88 kD, isoelectric point is 9.05, and liposolubility index is 79.05. Phylogenetic tree analysis showed that EjAGL6 and MdAGL6 had high homology and clustered into the same branch. (2) Protein sequence alignment suggested that EjAGL6 includes M domain (57 aa), I domain (30 aa), K domain (82 aa) and the C domain (74 aa), and two highly conserved motifs of AGL6 motifs I and II in the Cterminal domains. (3) Subcellular localization analysis indicated that the functional region of EjAGL6 protein was located in the nucleus, suggesting it has subcellular localization characteristics of MADSbox transcription factor. (4) The qRTPCR analysis showed that EjAGL6 was expressed in diploid and triploid loquat early and late flowering cultivars. Among them, EjAGL6 expression level was mainly concentrated in the latter three stages of flower development, including the stages of florets (S6), white corollas of floral buds (S7) and full bloom (S8), and the EjAGL6 expression level of diploid and triploid early flowering cultivars were higher in white corollars stage of floral buds. (5) The expression level of EjAGL6 gene in transgenic A. thaliana was significantly higher than that in wildtype A. thaliana. Phenotype observation of transgenic plants showed that overexpression of EjAGL6 gene in A. thaliana could advance flowering time of transgenic A. thaliana by one week. The results showed that EjAGL6 gene could promote the flowering time of loquat earlier, suggesting that EjAGL6 gene plays a key role in regulating flowering time during white corollas stage of floral buds.

Abstract:βketoacylCoA synthase (KCS) is the ratelimiting enzyme in the biosynthesis of very long chain fatty acids (VLCFAs). In this study, Lilium brownii var. viridulum Baker ‘Huangtianba’ was used as material, the CDS sequences of LbKCS5 and LbKCS17 genes were cloned by RTPCR using cDNA as a template, and sequence analysis, qRTPCR were performed to study their gene expression and stress induction analysis. The results showed that: (1) LbKCS5 and LbKCS17 contained 689 bp and 1 238 bp complete reading frames (ORFs), encoding 186 and 291 amino acids, respectively. Sequence similarity between LbKCS5 and oil palm KCS5，LbKCS17 and lotus KCS17 were 82.61% and 77.62%, respectively. (2) Expression level analysis indicated that both LbKCS5 and LbKCS17 were expressed in the vegetative organs of lily, with the highest expression in leaves and the least in roots. In floral organs, petals had the two genes’ lowest expression, the highest expression levels of LbKCS5 and LbKCS17 were in stamens and anthers, respectively. During the growth and development of flower buds, the two genes’ expression increased first and then decreased, reaching a peak at the yellow bud stage in petals; in leaves LbKCS5 reached the highest at the yellow bud, while the expression of LbKCS17 was generally low. (3) The transcriptional expression levels of these two genes surged under dehydration stress, and low temperature can induce LbKCS5 expression rinsing, but reduce the expression of LbKCS17; Our results show that LbKCS5 and LbKCS17 were expressed in different organs of lily and responded to dehydration and low temperature stresses, which provided a feasible approach and theoretical supporting for future studies on improving these two stresses tolerance and breeding of new varieties of lily.

Abstract:Cytochrome P450 monooxygenase (CYP450) is the largest enzyme family involved in plant metabolism, among which CYP734A subfamily members are widely involved in the inactivation of plant hormone Brassinosteroids (BRs). In order to analyze the effects of BRs on Hordeum vulgare L. var. nudum Hook. f.(highland barley), which is a characteristic plant in QinghaiTibet plateau, we treated the seedlings of highland barley cultivar ‘Dulihuang’ with the synthetic hormone 24epibrassinolide (24eBL) or BRs synthetic inhibitor brassinazole (BRZ). In order to deeply analyze the function of HvBAS1, we cloned the cDNAs from highland barley by RTPCR, and detected their expression characteristics by realtime quantitative PCR. The results showed that: (1) 24eBL could significantly promote the growth of highland barley seedlings, while BRZ was opposite. (2) Two subfamily members of CYP734As were cloned from highland barley. Due to their high homology with Arabidopsis BAS1, they were named HvBAS11 and HvBAS12. HvBAS11 was 1 629bp in length and encoded 542 aa, while HvBAS12 was 1 689 bp in length and encoded 562 aa. The homology of amino acid sequences between them was 76.42%. The results of subcellular localization predicted that both of them existed in endoplasmic reticulum. (3) Realtime quantitative PCR detection showed that the expression patterns of HvBAS11 and HvBAS12 were completely different, in which the expression of HvBAS11 in the roots was higher than that in the leaves, while the expression of HvBAS12 in the leaves was higher than that in the roots. With the increase of seedling age, the expression of HvBAS11 in the roots showed a trend of first increasing and then decreasing, but HvBAS12 decreased firstly and then increased in leaves. After BRZ treatment, both HvBAS11 and HvBAS12 were significantly downregulated compared with the control, and the expression level of HvBAS12 were decreased even more. The results indicated that both HvBAS11 and HvBAS12 were probably involved in inactivation of endogenous BRs in highland barley, but their functions were different.

Abstract:Ampelopsis s. str. is a genus of deciduous vines from the grapevine family Vitaceae. It is mainly distributed in the temperate regions of the Northern Hemisphere with a high species richness in east Asia.In this study, 37 samples from 15 species of Ampelopsis s. str. were sequenced using 5 chloroplast (trnLF, rps16, psbAtrnH, atpBrbcl, and trnKpetN) and 2 nuclear markers (ITS and GAI1) for exploring the phylogenetic relationships within the genus, the evolution of leaf traits, and the evolution of biogeographic.The results showed that: (1) supported the monophyly of the genus and all species from eastern Asia form a clade with high support values. (2) Chloroplast results revealed that the eastern Asian lineage is divided into two clades, largely consistent with the geographic pattern of the SinoJapanese and SinoHimalayan subregions of the eastern Asian flora. (3) The morphological evolution analysis showed that palmate compound leaf was the ancestral characteristic, and the morphological characters of leaf had independent origin and evolution for many times. (4) The Ampelopsis s. str. was suggested to be most likely originated in North America with migration to the Europe in the late Oligocene to early Miocene via the North Atlantic Land Bridge, followed with spread to eastern Asia in the middle Miocene. Ampelopsis s. str. was well diversified in eastern Asia, probably resulted from the warm climate in the middle Miocene, less impact of the Quaternary glaciation and the complex topography of eastern Asia.

Abstract:Grain length is one of the components of rice grain shape that directly affects grain yield. Besides, grain length is one of the important indicators of rice quality. In this study, the longgrain restorer line R204 containing the blast resistance gene Pigm1 was used for genetic analysis of grain length. Through mapbased cloning, the longgrain gene was identified and its application in breeding was analyzed through analyzing cross combinations. The results showed that: (1) the GL121 (grain length 121) locus is under the genetic control of a dominant Mendelian factor. (2) Through mapbased cloning, GL121 was initially located to a chromosomal region of about 4.5 Mb between Inde123 and Inde127 on chromosome 12 of rice. (3) Further genetic analysis delimits the GL121 locus to a chromosomal region of 900 kb between markers Inde10 and Inde16. (4) F₁ hybrids from the test crosses with ‘Dingyuan A’, ‘Qiyuan A’ and ‘Qingyuan A’ showed the longgrain phenotype of the R204 line, whereas F₁ hybrids from the test cross with ‘Liangxiang A’ showed the grain length phenotype of the ‘Liangxiang A’ that is longer than that of the R204 line. The research showed that the GL121 locus is under the genetic control of a dominant Mendelian factor, which may be a new gene controlling grain length. Moreover, this study provides a foundation for cloning, characterization and functional analysis which are essential for molecular breeding of the grain type gene GL121.

Abstract:With Optical microscope and scanning electron microscope (SEM), the study carried out on the morphological and structural traits of the development process of Podocarpus macrophyllus male cones, microspores and gametophytes, so as to reveal the microsporogenesis and the development law of male gametophyte, and provide embryological evidence for the reproduction and cross combination of P. macrophyllus. Results showed that: (1) the male cone of P. macrophyllus differentiates in July each year, and the pollen maturation was in May of the following year. In this period of time, the male cone had developed from single oval to two or three adnate catkins. Microspore leaves spirally grew on cylindrical inflorescence axis, and two microsporangiums coalesced at the base of abaxial surface of each microspore leaf. (2) During the development of microsporangium wall, epidermis, endothecium, middle layer and tapetum appeared from outside to inside, and each of them composed of one layer of thinwalled cells. Before shedding, the latter two were decomposed and absorbed. (3) There were differences in the development time of sporogenous cells in the same microsporangium, and the tetrad that formed after the meiosis of the microspore mother cell had two types of arrangement: tetrahedral and decussate types. Mature male gametophyte comprised germ cells and pollen tube cells, and the first and second prothallial cells that appear during development had resolved and disappeared. (4) Electroscope images showed that the pollen grains of P. macrophyllus are typical pinetype pollens with one air sac on each side and a germinal furrow on the far pole surface and the surface of pollen was textured or wrinkled. These results may provide an embryological basis for the reproduction and hybrid combination.

Abstract:Periploca sepium Bunge is a vine shrub of the Asclepiadaceae family Periploca genus, and is a ground cover plant for vertical greening in courtyards, rockeries and forest edges. In order to explore the growth rhythm of P. sepium and flower bud differentiation process in Yanbian, Jilin Province, in this paper, we sowed P. sepium seeds collected from the Jilin Xianghai Wetland Reserve in the experimental field of the School of Agriculture, Yanbian University, and observed the growth rhythm for five consecutive years. The morphological and anatomical characteristics of the growth rhythm and flower bud differentiation of P. sepium were studied by field observation and conventional paraffin slicing. The results showed: (1) in Yanbian, Jilin Province, the first and the second year, P. sepium conducts mainly for vegetative growth, and the third year can form flower buds and enter the reproductive growth period. (2) In Yanbian, the P. sepium blooms in late May, the bud period from late May to early June, the initial flowering period from midJune to midJune to late June, late June to early July, the fruiting period from early July to midOctober. (3) P. sepium starts to enter flower bud differentiation in late May. The bud differentiation process of P. sepium can be divided into undifferentiated stage, initial phase of differentiation, calyx primordium differentiation, petal primordium differentiation, stamen primordium differentiation, pistil primordium differentiation and paracorolla differentiation stage. The above research results clarify the anatomical characteristics of P. sepium growth rhythm and flower bud differentiation in Yanbian area, and play a practical role in landscaping application.

Abstract:Pot experiment was conducted to set up gradient salinealkali environment (0, 1.5, 3.0, 4.5, 6.0 and 7.5 g·kg^-1) and inoculate Rhizophagus intraradices (Ri). The changes of seedling height growth, leaf photosynthesis, chlorophyll fluorescence parameters and stress resistance physiological indexes of Pyrus betulifolia seedlings were compared and analyzed. We studied the effects of arbuscular mycorrhizal fungi inoculated with mixed salinealkali on the growth and stress resistance of P. betulifolia seedlings to provide a theoretical basis for mycorrhizal P. betulifolia afforestation in salinealkali environment. The results show that: (1) R. intraradices could form a good symbiosis with the root system of P. betulifolia, but the infection rate decreased to 47.98% and 32.97% at 6.0 g·kg^-1and 7.5 g·kg^-1 saline alkali concentration, respectively. (2) Under salinealkali stress, Ri inoculation significantly increased height growth and biomass, photosynthetic pigment content and net photosynthetic rate of P. betulifolia leaves. Especially at high saline alkali concentration (6.0 g·kg^-1and 7.5 g·kg^-1), RI inoculation significantly increased the stomatal conductance and intercellular carbon dioxide content of P. betulifolia leaves, which was conducive to the increase of photochemical quenching coefficient and the decrease of non photochemical quenching coefficient, and promoted the improvement of actual photochemical efficiency. (3) Ri inoculation significantly decreased the cell membrane permeability and the content of MDA, significantly increased the activities of superoxide dismutase and peroxidase, and increased the contents of soluble sugar and soluble protein in the leaves of P. betulifolia seedlings. It was found that inoculation with R. intraradices could significantly enhance the activities of antioxidant enzymes and osmotic mediation ability of P. betulifolia under salinealkali stress, effectively enhance its growth and photosynthetic efficiency, and finally alleviate the damage caused by saline alkali stress. Therefore, the implementation of mycorrhizalization of P. betulifolia seedlings can effectively improve the growth and stress resistance of seedlings in salinealkali soil, which is beneficial to play a greater role in the comprehensive management of salinealkali soil.

Abstract:In this study, Monto and Veriveria nermorlis ecotypes of vetiver grass ［Chrysopogon zizanioides (L.) Roberty］ were treated with cadmium nitrate solution at different concentrations (0, 200, 800, 2 000 μmol·L^-1) for 7 days. We compared and analyzed the differences of leaf growth status, chlorophyll fluorescence parameters, cadmium accumulation, subcellular distribution and chemical forms distribution between the two vetiver ecotypes to determine the tolerance and accumulation characteristics of the two types of vetiver grass to cadmium. The results showed that: (1) under middle and high cadmium concentrations, the growth status of Monto was better than that of Veriveria nermorlis, and the chlorophyll fluorescence parameters (F_m, F_v/F_m and F_v/F_o) of Monto were higher than those of Veriveria nermorlis, and the translocation factor, bioconcentration factor and the cadmium accumulation in the leaves and roots of Monto were lower than Veriveria nermorlis. (2) It was also found that more than 95% of accumulated Cd existed in the cell wall and soluble components of the leaves and roots of both ecotypes. The proportions of Cd in the cell wall of leaves and roots of Monto, and leaves of Veriveria nermorlis were increased with the rise of Cd concentration, and the proportions of Cd in soluble fraction were decreased gradually, while those of Veriveria nermorlis roots displayed the opposite trend. And the proportions of Cd in the cell wall of leaves of Monto were higher than Veriveria nermorlis. (3) Analysis of chemical forms of Cd distribution showed that NaClextracted Cd had the highest ratio in leaves, while ethanol and NaClextracted Cd were dominant in roots of Monto and Veriveria nermorlis. Further, a higher proportion of ethanolextracted Cd and a lower proportion of NaClextracted Cd were observed in the roots of Monto. This work can suggest that Monto was more tolerant to cadmium stress comparing to Veriveria nermorlis, which may be mainly associated with the lower Cd accumulation, bioconcentration factor and translocation factor, and higher proportions of Cd in the cell wall of leaves and higher proportions of ethanolextracted Cd in roots of Monto.

Abstract:In order to explore the growth and physiological characteristics of stress resistance in seedling of Viola tricolor under NaHCO₃ stress, we treated the seedlings of V. tricolor with different concentrations of NaHCO₃ ［0 mmol·L^-1 (CK), 25 mmol·L^-1, 50 mmol·L^-1, 100 mmol·L^-1, 150 mmol·L^-1, 200 mmol·L^-1］, and determined the height growth, osmotic regulation substances, antioxidant enzyme activity, photosynthetic pigment content, and malondialdehyde (MDA) content on the 7th day and 14th day. The results showed that: (1) compared with CK, the height growth of V. tricolor was significantly increased when NaHCO₃ concentration was less than 50 mmol·L^-1, and close to CK when NaHCO₃ concentration was 100 mmol·L^-1, but significantly decreased when NaHCO₃ concentration was higher than 100 mmol·L^-1. (2) On the 7th day, the contents of soluble sugar (SS), soluble protein (SP) and free proline (Pro) in V. tricolor leaves were significantly higher under NaHCO₃ treatments than under CK, while on the 14th day, the contents of SS under all NaHCO₃ concentration, SP under 50 mmol·L^-1, Pro under 150 and 200 mmol·L^-1 were significantly higher than under CK. (3) On the 7th day, the activity of superoxide dismutase (SOD) in V. tricolor leaves was significantly increased under NaHCO₃ treatments than under CK, while the activities of peroxidase (POD) and catalase (CAT) had no significant change. On the 14th day, the contents of CAT under all NaHCO₃ concentration, POD under 50 mmol·L^-1, SOD under 100 and 150 mmol·L^-1 were significantly higher than under CK. (4) MDA content in V. tricolor leaves increased gradually with the increase of NaHCO₃ concentration, and was significantly higher than CK. (5) Compared with CK, chlorophyll content in V. tricolor leaves did not change significantly on the 7th day, while decreased significantly under 150 or 200 mmol·L^-1 NaHCO₃ concentration on the 14th day. The results indicated that V. tricolor could tolerate lower than 100 mmol·L^-1NaHCO₃ concentration and NaHCO₃ had a dose effect of promoting plant height growth at low concentration and inhibiting plant height growth at high concentration. V. tricolor could alleviate the peroxidation damage induced by NaHCO₃ stress through increasing the contents of osmotic regulatory substances and enhancing the activities of antioxidant enzymes, and thus improved the tolerance of V. tricolor seedlings.

Abstract:In this study, oat cultivars ‘Yanke 2’ (high grain cadmium accumulation, Yh) and ‘20091971’ (low grain cadmium accumulation, Yl) were used as materials, and pot experiments were carried out under the condition of soil Cd stress. The changes of plant growth, leaf photosynthetic physiology and antioxidant enzyme activities of the two types of oats were measured, and the differences in the responses of the two cultivars to Cd stress were discussed. The results showed that: (1) under Cd stress, the plant growth, gas exchange parameters and chlorophyll fluorescence parameters of high Cd accumulating oat cultivar (Yh) and low Cd accumulating oat cultivar (Yl) were inhibited, and the dry weight per plant, P_n and qP were the most prominent. The decrease rates of Yh and Yl were 38.2% and 40.8%, 35.0% and 57.1%, 14.7% and 27.3%, respectively. (2) Cd stress induced the activities of antioxidant enzymes in leaves of the two types of oat cultivars, especially SOD activity was significantly enhanced, Yh and Yl increased by 41.9% and 44.9%, respectively; at the same time, Cd stress significantly increased MDA content, Yh and Yl increased by 22.2% and 18.1%, respectively. The study found that under Cd stress conditions, compared with the low Cd accumulation varieties, the high Cd accumulation varieties had higher biomass and antioxidant enzyme activities, as well as stronger net photosynthetic rate and excellent chlorophyll fluorescence characteristics, showing a relatively high level of chlorophyll fluorescence and strong Cd resistance.

Abstract:In this study, the sixyear Catalpa bungei clone (“91”) was fertilized via three fertilization schemes, i.e. the integration of water and fertilizer (WF), hole fertilization (HF) and no fertilization (CK) for analyzing the effect of fertilization on the growth of C. bungei. In addition, this paper also studied the effect of fertilization on the content and temporal dynamics of the nonstructural carbon (NSC) in tree organs, and explored the response mechanism of NSC allocation to fertilization, providing a theoretical basis for evaluating the carbon pool of C. bungei stand. The results showed that: (1) undergoing fouryear fertilization, the tree height and diameter at breast height (DBH) of HF increased 4.7% and 7.1%, and those of WF increased 7.1% and 20.5% compared with CK, respectively. (2) Different fertilization regimes did not significantly change the soluble sugar content in each organ, but the WF significantly increased the accumulation of starch and total NSC in roots. The soluble sugar and total NSC contents were more distributed in leaves and coarse roots, and starch content was higher in roots. (3) Different fertilization regimes did not significantly change the soluble sugar content during each growth period, but the WF significantly increased the starch and total NSC content during the initial and final period of growing season. The sugar and total NSC contents in leaves were consistently consumed throughout the growing season. One part of the sugar in branches was consumed to support leaf growth, and another part was stored in the form of starch. The NSCs from leaves and branches captured by roots were converted into starch, then stored to help the tree fight low temperatures. In conclusion, C. bungei followed the NSC allocation strategy of “carbon consumption (initial stage)carbon consumption (middle stage)carbon accumulation (final stage)”. In conclusion, the application of water and fertilizer integration technology could significantly improve the biomass and productivity of C. bungei, which was worthy of priority in forest fertilization in the future.

Abstract:Based on the quality inspection and meteorological data of wine grapes from 14 wineries and vineyards at the eastern foot of Helan Mountain in Ningxia from 2018 to 2020, we analyzed the key meteorological factors affecting the quality components of wine grapes, and constructed the relationship model between the quality components of wine grapes and meteorological factors, to improve the utilization efficiency of climate resources in the garden, improve the scientific management level of vineyards, and provide reference for actively adapting to climate change. The results show that: (1) meteorological factors are important indicators that affect the quality of wine grapes. They have a direct or indirect impact on grape quality during the entire growth period of grape growth, and the period with the greatest impact on quality is July to August and the period before harvest weather conditions for the month. (2) The degree of influence of meteorological factors from large to small is pH, anthocyanin, titratable acid, total phenol, sugaracid ratio, solidacid ratio, soluble solids, tannin, reducing sugar content. (3) The changes of humidity and minimum temperature have great influence on the quality components of wine grapes. (4) Reducing the average relative air humidity in July and increasing the average relative air humidity in August is beneficial to the reduction of pH; combined with the accumulation of acid content, the amount of vineyard irrigation should be increased in August in order to reduce the impact of climate warming. The sugar content of wine grapes is high; (5) the moderate high temperature 20d before harvest and the high humidity environment 10 d before harvest are conducive to the accumulation of total phenols, but the latter will reduce the tannin content in the fruit; if the lowest temperature and highest temperature in the environment are both low 20 d before harvest, it is not conducive to the accumulation of anthocyanins; when the GDD reaches about 280 ℃·d from September to before harvesting, the sugaracid ratio reaches the maximum value.

Abstract:In order to clarify the effect of soil moisture content on the growth and nitrogen uptake preference of ephemeral plants in desert ecosystems, we selected four dominant ephemeral plants in the Gurbantunggut Desert, Eremopyrum orientale, Erodium oxyrhinchum, Centaurea pulchella, and Lappula patula as the research object. Through the potted water control experiment, setting 3 water gradients: drought treatment (W₁, soil water content 2%)， normal moisture treatment (W₂, soil water content 8%), wet treatment (W₃， soil water content 14%). Using the ¹⁵N isotope tracer method, we studied the effects of water on biomass and nitrogen uptake strategies of four plant species. The results showed: (1) with the increase of the soil moisture content, the aboveground, underground and total biomass of the four ephemeral plants showed an increasing trend, and the growth rate is the highest under normal water treatment, and the biomass accumulation rate was different among different species in the same lifeform. However, the rootshoot ratio of four ephemeral plants decreased significantly with the change of soil moisture content. (2) Under different water treatments, the ¹⁵N uptake rates of the four ephemeral plants for different forms were as follows: nitrate nitrogen > ammonium nitrogen > glycine, and the uptake rates of the three forms of nitrogen and total nitrogen increased with the increase of the water gradient. (3) In drought treatment, nitrate nitrogen was the most preferred nitrogen form to be absorbed by the four ephemeral plants. With the increase of soil moisture content, the nitrogen form preference of Eremopyrum orientale and Centaurea pulchella were not changed. However, when the water continued to increase to wet treatment, the contribution rate of ammonium nitrogen to the nitrogen uptake of Erodium oxyrhinchum and Lappula patula exceeded the nitrate nitrogen, became the most preferred form of nitrogen absorbed by these two plants.

Abstract:Legumes are important pioneer species in arid ecosystems such as deserts, and are also the main source of available nitrogen in ecosystems. In order to clarify the relationship between desert legumes and habitat soil factors, this study took Astragalus flexus and Astragalus arpilobus as materials, which are widely distributed in the Gurbantunggut Desert. The physicochemical properties of different soil depths (0-5, 5-10, 10-15 cm) were measured, and the relationship between the stoichiometric characteristics and soil factors of the two desert legumes was compared and analyzed. The results showed that: (1) the carbon (C), nitrogen (N) and phosphorus (P) contents of A. flexus were 373.35, 25.66 and 1.03 mg·g^-1, respectively, which were higher than those of A. arpilobus, 331.53, 19.59, and 0.66 mg·g^-1, and the contents of N and P were significantly different (P<0.05); the C∶P and N∶P of A. flexus were 374.38 and 25.75, respectively, which were significantly higher than those of A. arpilobus, 166.09 and 10.12 (P<0.01), while the C∶N of A. flexus (14.62) was lower than that of A. arpilobus (16.99), but there was no significant difference in C and C∶N between the two plants. (2) The organic carbon (SOC), total nitrogen (TN), and total phosphorus (TP) contents of the legume habitat soil in the 0-5 cm soil layer were the highest, and gradually decreased with the deepening of the soil layer; the soil stoichiometric ratio SOC∶TN and SOC∶TP increased gradually with the deepening of the soil layer, while the value of TN∶TP gradually decreased with the deepening of the soil layer; the lower N content and TN∶TP indicated that the soil in this area belonged to the type of N deficiency. (3) The correlation between the two desert legumes and the soil stoichiometric characteristics at different levels was not consistent, among which: there was a negative correlation between TN and N∶P, and a very significant negative correlation between TP and P. And there was a positive correlation between TP and C∶N, and a very significant positive correlation between SOC∶TN and N∶P in 0-10 cm soil layer of A. flexus. In soil layers 10-15 cm, there was a positive correlation between SOC∶TN and N∶P. Only P in A. arpilobus had a very significant positive correlation with the SOC∶TP in the 0-5 cm soil layer, while most of the stoichiometric characteristics showed no correlation. (4) There was a very positive correlation between the phytostoichiometric index P of A. flexus and the electrical conductivity (EC) in the 5-10 cm soil layer, there was a positive correlation between the available potassium (AK) and N in the 10-15 cm soil layer. The A. arpilobus was negatively correlated with available phosphorus (AP) and N, AP and N∶P in 0-5 cm soil layer, but not with other soil layers. The research showed that the soil N content and TN∶TP ratio in the Gurbantunggut Desert were relatively low, the soil N element was poor, and the nutrient content of the leguminous soil in this area was generally low; the main limiting element for the growth of A. flexus in this area was P, The main limiting elements for the growth of A. arpilobus were N and P; and the phytochemistry characteristics were not directly determined by soil nutrient characteristics, the significant interspecific differences showed the importance of plant genetic traits in the coupling relationship between soil and plant quantitative traits.

Abstract:Understory herbaceous plants are an important part of forest ecosystems and have important ecological functions for maintaining the succession and development of forest communities. In this study, Picea crassifolia forest (Ⅰ), Betula albosinensis forest (Ⅱ), Populus cathayana forest (Ⅲ), Broadleaved mixed forest (Ⅳ) and Coniferous and broadleaved mixed forest (Ⅴ), these five different stand types of plantations in Huzhu Beishan Forest Farm, which located in the east of Qinghai Province, were selected as the research object. Typical sampling method was used to select four 20 m by 20 m plots in each stand, and each tree in the plot was examined. Five 1 m by 1 m herbaceous quadrats were set in each plot. Understory herbaceous plants were investigated and recorded, and soil samples of five small quadrats were collected and analyzed. Grey correlation method was used to analyze the relationship between understory herbaceous diversity and stand characteristics, soil nutrient characteristics, in order to clarify the dominant factors affecting understory herbaceous species diversity, and provide scientific basis for local plantation management. The results showed that: (1) there existed 86 herb species belonging to 74 genera of 30 families. Among them, the number of families, genera and species in type Ⅴ was the largest (49 species, 42 genera, 25 families), and that in type Ⅰ was the least (27 species, 26 genera, 17 families). In type Ⅰ, Ⅲ and Ⅳ, the important values of Fragaria vesca in herb layer were the highest (44.42%, 20.29% and 23.05%, respectively). In stand Ⅱ and Ⅴ, the dominant species were Parasenecio hastatus, Fragaria vesca, and Lolium perenne, and their important values were 20.97%, 13.95%, 13.68% and 8.34%, 16.83% and 27.82%, respectively. (2) The species richness (S), ShannonWiener diversity index (D) and Simpson diversity index (H) of the five stands were significantly different (P<0.05), but the Pielou evenness index (J) was not significantly different. These indexes were lower in conifer pure forest (Ⅰ) than those in the broadleaved pure forests (Ⅱ and Ⅲ) and mixed forests (Ⅳ and Ⅴ). (3) There were no significant differences in stand density (SD), average diameter at breast height (DBH), average tree height (H) and average crown width (CW) among different stand types, but these stand factors in different forest types decreased in order: coniferous and broadleaved mixed forest > broadleaved mixed forest > broadleaved pure forests > conifer pure forest. (4) The contents of soil alkalihydrolyzed nitrogen (AN), available phosphorus (AP), available potassium (AK), soil organic matter (SOC) and potential of hydrogen (pH) were higher in the mixed forests and broadleaved pure forests than those in conifer pure forest. With the increase of soil depth, the contents of AN, AP, AK, SOC decreased and pH increased. (5) The species diversity of understory herbaceous plants in the forest ecosystem responded significantly to the stand factors and soil nutrient characteristics, and DBH was the most important stand factor affecting the herb diversity, alkalihydrolyzed nitrogen is the most important soil nutrient characteristic. Therefore, in the future forest reconstruction, we should improve the artificial forest construction mode, optimize the stand factors and enhance the soil fertility, so as to improve the diversity of the herbaceous plant and maintain the stability and sustainable development of the forest ecosystem.

Abstract:This study identifies one diatom species as Tabularia fonticola (Hustedt) C.E. Wetzel & D.M. Williams after examining the specimens collected from the Wu River, which runs through the Suining County of Hunan Province, by using light and scanning electron microscopy. The observation results demonstrate that the identified T. fonticola has the following diagnostic characters: (1) linearlanceolate valve outline with wide sternum and shortened and wide striae. (2) Thickened silica virgae and vimines. (3) Areola occluded by cribrum composed of a few transapical silica bars. (4) Only one rimoportula produced at an apex for each valve. (5) Ocellulimbus with regularly arranged porelli. (6) Open valvocopula. This article reports the ultrastructure characters of the prenormal frustule of T. fonticola for the first time. The study results not only improve the understanding of the ultrastructure of T. fonticola, but also add a new geographical distribution region for it.

Abstract:During the survey of forestry seeding resource in 2020, a new Whytockia species was discovered in Changting, Fujian Province and named as Whytockia minxiensis after the continuous monitor for 2 years while its description and pictures were provided. It is distinguished from Whytockia sasakii by its 2 room ovary, oval stigma, densely pubescent leaf back, pubescent calyx. The holotype was deposited in the herbarium of Forestry College of Fujian Agriculture and Forestry University (FJFC).

Abstract:Drought is one of the important factors limiting the growth and development of sunflowers. To investigate the molecular mechanism of drought resistance in sunflower seedlings, in this study, we used 150 F₇ recombinant selfincompatible line populations constructed by crossing K55 and K58 as materials, and phenotypically determined the relative leaf conductivity, chlorophyll content, leaf area, relative leaf water content, and root length under two water treatment conditions of normal watering and drought stress. With the previous established genetic linkage maps of SNP and SSR markers we located five droughtrelated traits by the composite interval mapping method. The results showed that: (1) a total of 11 QTL loci were localized, 5 under normal irrigation conditions and 6 under drought stress conditions, with phenotypic contributions ranging from 0.768% to 7.547%. 3 QTL loci were localized on Chr. 5, with the most loci. (2) 62 droughtrelated candidate genes were screened within the QTL confidence interval, including rna23019, rna23004, rna22661, rna22193, rna23294, rna22783 on qLA81 and rna40140 on qCC131, which can be used as subsequent gene cloning and functional analysis. This study lays the foundation for drought resistance research and its genetic improvement in sunflowers.