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[Objective] The present paper aimed to screen leguminous plants suitable for improving the soil of bauxite mine reclaimed soil and provide a reference basis for sustainable agricultural development in mining areas. [Method] Seven legumes, including Sesbania cannabina, Vicia sativa, Astragalus sinicus, V. villosa, Medicago sativa, Stylosanthes guianensis and Coronilla varia, were planted in the reclaimed soil of the Pingguo bauxite mine in Guangxi, and the biomass, presence of root nodules, nutrient content, nitrogen fixation efficiency, biological nitro- gen fixation, soil nutrients, calcium and magnesium ion content, total aluminum and active aluminum content of each legume were determined. The legumes suitable for planting in bauxite mine reclamation soil were screened through principal component analysis, and a partial least squares path model (PLS-PM) was established to explore the factors that affected the biological nitrogen fixation of legumes in bauxite mine reclamation soil. [Result] Among the seven legumes, A. sinicus had the highest below-ground biomass(1.961 g/pot) and above-ground bio-mass (0.344 g/pot), C. varia had the lowest below-ground biomass (0.387 g/pot) and above-ground biomass (0.099 g/pot) while Sesbania had the highest N(7.98% ), P(2.999 g/kg), and K(19.828 g/kg) contents. In terms of nodulation, only Sesbania, A. sinicus, and C. varia had root nodules, while the rest of the legumes did not nodulate. Among the three nodulated legumes, S. cannabina had the highest nitrogen fixation efficiency (80.01%) and biological nitrogen fixation (0.077 g/pot). Principal component analysis of three leguminous plants based on evaluation factors including plant nutrient content, biomass, biological nitrogen fixation, and nitrogen fixation efficiency as evaluation factors showed that comprehensive score of S. cannabina repens was the highest (2.30 points). PLS-PM pathway analysis showed that the biological nitrogen fixation of legumes in bauxite mine reclamation soil was directly influenced by plant nutrient content and soil active aluminum and pH, soil nutrients, and types of plants indirectly influenced the biological nitrogen fixation of legumes by affecting plant nutrient content and soil active aluminum. [Conclusion] S. cannabina, A. sinicus, and C. varia are capable of nodulating and improving the pH, available K, ac- tive aluminum, organic matter content, and biological nitrogen fixation of the reclaimed soil in bauxite mines. Based on the comprehensive e- valuation, S. cannabina is considered as the most suitable legume plant for planting in the reclaimed soil of bauxite mines and can be promo- ted and applied as a legume plant for nitrogen fixation and soil improvement in bauxite mining areas. [ABSTRACT FROM AUTHOR]

【Objective】The present paper aimed to establish the evaluation method of heat resistance of leek resources, select heat-resistant leek varieties, and solve the problem of shortage of heat-resistant leek varieties in Guangxi.【Method】Taking three kinds of local germplasm resources of leek（marked as A, B, C, D, E, F, G, H and I, respectively） of Guangxi large leaf leek, wide leaf leek and thin leaf leek collected from the general survey of germplasm resources by Ministry of Agricultural and Rural Affairs（2015-2020） as test materials, the changes of the maximum growth length of leek leaves, the newly increased aboveground biomass and the contents of chlorophyll, proline and malondialdehyde after 7 days of high temperature stress at 38 ℃ were measured. Combined with field natural high temperature stress（field group） actual heat resistance performance, the heat resistance of different types of leek was comprehensively evaluated by multivariate statistical analysis（variance analysis, principal component analysis, membership function method and cluster analysis） methods.【Result】Under high temperature stress of 38 ℃,the maximum leaf growth length and the newly increased biomass of 9 leek germplasms of the three types in Guangxi were extremely significantly decreased compared with their proper temperature control（CK）（P＜0.01）.The largest decline was the type of large-leaved leek, and the smallest decline was the type of fine-leaved leek. Chlorophyll content decreased to different degrees, of which the largest decline was the type of leek with large leaves, and the smallest decline was the type of leek with thin leaves. The content of MDA increased to different degrees, of which the largest increase was the type of leek with large leaves, and the smallest increase was the type of leek with thin leaves. Pro content increased to different degrees, of which, the largest increase was the type of leek with thin leaves, and the smallest increase was the type of leek with large leaves. The comprehensive evaluation results showed that the heat tolerance of the three kinds of local leek germplasm resources of leek in Guangxi was ranked as follows: leek with thin leaves＞leek with broad leaves＞leek with large leaves. Germplasm G（No.2016451159） and Germplasm I（No.2016453604） had the strongest heat tolerance among the nine leek germplasms, and Germplasm C（No.SC20191200） had the weakest heat tolerance.【Conclusion】The maximum growth length of leaves, new aboveground biomass and the content of chlorophyll, Pro and MDA contents were used as the evaluation indicators of heat tolerance of leek germplasm resources, the heat tolerance of three kinds of leek germplasm resources in Guangxi can be ranked as follows: Leek with thin leaves＞ leek with broad leaves＞leek with large leaves by variance analysis, principal component analysis, membership function and cluster analysis. Germplasm G and germplasm I were determined to be more heat-resistant, while germplasm C was the least heat-resistant. [ABSTRACT FROM AUTHOR]

Poor conditions, and quite differences in seasonal climate environment in coastal sandy land makes it difficult for plants to survive. Ipomoea pes-caprae is an important sand-fixing plant widely distributed in southern coastal sandy land. In order to explore the adaptation mechanism of I. pes-caprae to environmental changes in different seasons, the seasonal changes of its leaf physiological traits were studied. In this paper, I. pes-caprae grown up naturally in coastal sand of Guangxi was taken as experimental material, and the physiological indexes such as the contents of chlorophyll, the contents of osmotic substance, antioxidant enzyme activities and chlorophyll fluorescence parameters of the I. pes-caprae leaves in different seasons were measured, and the correlation analysis and principal component analysis were also carried out. The results were as follows:（1） Chlorophyll contents had the same trend with season changes, which was significantly higher in spring than those in other three seasons, but chlorophyll a/b had no significant change among seasons.（2） Fv/Fm and Fv/Fo of chlorophyll fluorescence parameters also had the same change trends, which were significantly higher in summer and winter than those in spring and autumn.（3） Proline content increased gradually with seasons, and reached the highest level in winter. Soluble sugar content in winter was significantly higher than those in other three seasons. There was no significant differences in malondialdehyde（MDA） contents among seasons.（4） The activities of superoxide dismutase（SOD） and catalase（CAT） in spring were significantly higher than those in other seasons, but there was no significant differences among summer, autumn and winter. There was no significant differences in peroxidase（POD） activities among seasons.（5） There was a certain correlation between physiological indexes and climate factors by correlation analysis and principal component analysis. Temperature and sunshine duration significantly affected the contents of soluble sugar. Chlorophyll contents and antioxidant enzyme activities could better reflect the response of I. pes-caprae leaves to seasonal climate change. To sum up, the chlorophyll a/b can be kept stable by adjusting the contents of chlorophyll a and chlorophyll b, and meanwhile, the contents of osmotic adjustment substances and the activities of antioxidant enzymes can improve it to adapt to seasonal changes, among which photosynthesis and antioxidant enzymes system are the key factors affecting its seasonal adaptability. [ABSTRACT FROM AUTHOR]

The present paper aimed to analyze and evaluate the agronomic characters of cowpea varieties, and provide reference for screening cowpea varieties suitable for cultivation in N anning and its surrounding areas. [ Method] A comparative experiment of six cowpea varieties was carried out in Suwei Town, N anning City, Guangxi. Thirteen agronomic characters including double pods rate, high yield, pod longitudinal diameter, single pod weight and disease resistance were measured, and the correlation, principal component analysis and cluster analysis were used for comprehensive evaluation. [ Result] Correlation analysis showed that the number of branches per plant was the main reason affecting the number of seeds per pod and the number of main stem nodes. The length and width of pods were restricted by double pod rate and commercial pod rate. The rate of commercial pods and the number of main stem nodes had the greatest influence on single pod weight, and the increase of plant incidence would lead to the decrease of single pod weight. The results of principal component analysis showed that the cumulative contribution rate of variance of 13 agronomic characters of Guixiang No. 1, Gannong Chaoxnan and Chaoyue 708 ranked the top 3, and their comprehensive scores were 80. 37165,57. 56157 and 30. 08979,respectively. The top three varieties with comprehensive scores were Treasures No. 5,Jindou No. 8 and Taicheng Qianfeng, with comprehensive scores of -44. 20257, -50.45963 and -73. 36081, respectively. Cluster analysis showed that six cowpea varieties could be divided into two groups at the Euclidean distance of 15, among which Guirong No. 1, Gannong Chaoxnan and Chaoyue 708 in I group were characterized by high yield and strong disease resistance. Treasures No. 5, Jindou No. 8 and Taicheng Qianfeng of the second category had precocious characteristics. [Conclusion] Cowpea varieties Guijin No. 1, Gannong Chaoxnan and Chaoyue 708 have good performances in Suxu Town,Nanning City, Guangxi in yield and disease resistance, and are suitable for large-scale planting in Nanning and its surrounding areas. [ABSTRACT FROM AUTHOR]