观察表明:四合木和霸王的叶都有一条主脉和一条从基部出发止于叶缘中部的大侧脉;二者都为环孔材。同时,二者都以发达的皮层纤维、叶肉棚栏组织发达、叶肉细胞壁皱褶等共同的方式适应干旱环境。四合木和霸王有许多明显的解剖学差异,以不...观察表明:四合木和霸王的叶都有一条主脉和一条从基部出发止于叶缘中部的大侧脉;二者都为环孔材。同时,二者都以发达的皮层纤维、叶肉棚栏组织发达、叶肉细胞壁皱褶等共同的方式适应干旱环境。四合木和霸王有许多明显的解剖学差异,以不同的方式适应干旱环境,表现出系统上的差异,如四合木初生根为四原型,而霸王及蒺藜科绝大部分类群的根为二原型;四合木次生木质部为同型单列射线,多生活纤维而少木薄壁细胞,而霸王为同型单列和同型多列两类射线,以后者为主,并且多木薄壁细胞而不见生活纤维;四合本叶表皮的角质膜薄。密度丁字毛,气孔极下陷,而霸王叶表皮角质膜厚,无表皮毛,气孔下陷较小;此外,四合木基本组织中富含簇品细胞,茎中具特殊的油细胞,而霸王中不存在。这些差异特征支持一些分类工作者把四合木属从霸王亚科分出,新成立四合木亚科(Tetranenoideae Maet S. Z. zhang)。展开更多
Techniques have been developed for the vegetative propagation of Tetraena mongolica,a rare and endangered species endemic to the western Ordos Plateau in the northcentral portion of China.The purpose of the study was ...Techniques have been developed for the vegetative propagation of Tetraena mongolica,a rare and endangered species endemic to the western Ordos Plateau in the northcentral portion of China.The purpose of the study was to investigate the rooting characteris-tics of the plant species from the aspects of length and ages of cuttings,external hormone concentration,leaf retention,cutting orientations,and cutting positions.The results obtained from the experiments indicated that the rooting ratio of 2-year or 3-year old cuttings was larger than more than of 4-year old cuttings.The influence of external hormone concentration on rooting was ob-vious;the rooting ratio of cuttings was increased by external hormone treatment,especially when treated by ABT1(ABT No.1 Rooting Powder) 50 mg/L for 3 hours,in which case,the rooting ratio reached 91 percent.Leaf retention influenced rooting sig-nificantly;the rooting rate of cuttings became greater as the leaf retention increased.There was no significant difference in rooting capability between south and north orientations of the ortets.The rooting ratio of the cuttings obtained from the distal portions of shoots was significantly larger than those obtained from the middle and the basal portions of the shoots.On day three after treat-ment,calluses started appearing at the incisions of some cuttings dipped in 500 mg/L IAA(indole acetic acid).Most cuttings were healed or swelled,and 6 percent of cuttings rooted on day 6 after treatment.Higher rooting period occurred 7-10 days after the experiment was set up.展开更多
Two cDNAs encoding putative type 1 acyl-CoA： diacylglycerol acyltransferases （DGAT1, EC 2.3.1.20）, were cloned from Tetraena mongolica Maxim., an extreme xerophyte with high oil content in the stems. The 1,488-bp a...Two cDNAs encoding putative type 1 acyl-CoA： diacylglycerol acyltransferases （DGAT1, EC 2.3.1.20）, were cloned from Tetraena mongolica Maxim., an extreme xerophyte with high oil content in the stems. The 1,488-bp and 1,485-bp of the open reading frame （ORF） of the two cDNAs, designated as TmDGAT1a and TmDGAT1b, were both predicted to encode proteins of 495 and 494 amino acids, respectively. Southern blot analysis revealed that TmDGAT1a and TmDGAT1b both had low copy numbers in the T. mongolica genome. In addition to ubiquitous expression with different intensity in different tissues, including stems, leaves and roots, TmDGAT1a and TmDGAT1b, were found to be strongly induced by high salinity, drought and osmotic stress, resulting in a remarkable increase of triacylglycerol （TAG） accumulation in T. mongolica plantlets. TmDGAT1a and TmDGAT1b activities were confirmed in the yeast H1246 quadruple mutant （DGA1, LRO1, ARE1, ARE2） by restoring DGAT activity of the mutant host to produce TAG. Overexpression of TmDGAT1a and TmDGAT1b in soybean hairy roots as well as in T. mongolica calli both resulted in an increase in oil content （ranging from 37% to 108%）, accompanied by altered fatty acid profiles.展开更多
This paper uses Landsat TM images, GIS technology, Digital Elevation and Habitat Assessment Models to assess the habitat suitability of the endangered plant Tetraena mongolica in western Ordos Plateau of China by sele...This paper uses Landsat TM images, GIS technology, Digital Elevation and Habitat Assessment Models to assess the habitat suitability of the endangered plant Tetraena mongolica in western Ordos Plateau of China by selecting terrain, soil, climate, and human activity factors as assessment indices. The results are as follows： natural factors such as climate and terrain are not restrictive factors for the survival and development of T. mongolica in the research region, whereas human activity causes habitat quality of T. mongolica to change intensively in quantity and distribution. The area of less suitable habitat increased by 23.87 km2 compared to potential habitat suitability. Thus, in some areas, human activity may be a key factor causing the endangerment of T. mongolica. There were obvious differences of potential and practical habitat suitability between different habitat regions in the study area. The habitat quality was better in Wujiamiao, Dishan and Qipanjing regions, and worse in Wuda and Qianlishan regions.展开更多
Phytogenic mounds(nebkhas)formed by shrubs are a common phenomenon in arid and semiarid areas.The formation of nebkhas is accompanied by the appearance of the fertile island effect.Quantitative evaluation of the shrub...Phytogenic mounds(nebkhas)formed by shrubs are a common phenomenon in arid and semiarid areas.The formation of nebkhas is accompanied by the appearance of the fertile island effect.Quantitative evaluation of the shrub sand compost island effect is a key link in preventing soil erosion and nutrient loss.This study took the typical shrub Tetraena mongolica in desert areas as the research object and quantified the sand-trapping capacity of the shrub.We revealed the influence of sediment texture and volumetric soil water content on fertile islands during the development of T.mongolica nebkhas.The results showed that(1)the single shrub intercepted large amounts of sediments due to the high density of branches of T.mongolica,forming nebkhas that were positively correlated with the shrub size.(2)The overall soil nutrient content below the shrub was greater than the soil nutrient content outside the shrub,forming a typical fertile island effect.The soil organic carbon(SOC),alkaline hydrolytic nitrogen(AHN),available phosphorus(AP),and available K(AK)content all increased gradually with increasing nebkha volume.Compared with the deep soil of nebkhas,the nutrient content of the surface soil was generally higher.(3)There was a positive correlation between the volumetric water content and nutrient content in nebkhas.(4)The semi-ellipsoid shape of T.mongolica enabled it to intercept large amounts of coarse-grained material.Fine sand(100–250μm)was the main particle size in the sediment aggregates inside the nebkhas.The fine sand content generally increased with increasing shrub size.Redundancy analysis(RDA)revealed that the fine sand content of the nebkha sediments had a strong positive correlation with the soil nutrient content.This paper provides an example for evaluating the fertile island effect during the deposition process of nebkhas in the desert transition zone.展开更多
文摘观察表明:四合木和霸王的叶都有一条主脉和一条从基部出发止于叶缘中部的大侧脉;二者都为环孔材。同时,二者都以发达的皮层纤维、叶肉棚栏组织发达、叶肉细胞壁皱褶等共同的方式适应干旱环境。四合木和霸王有许多明显的解剖学差异,以不同的方式适应干旱环境,表现出系统上的差异,如四合木初生根为四原型,而霸王及蒺藜科绝大部分类群的根为二原型;四合木次生木质部为同型单列射线,多生活纤维而少木薄壁细胞,而霸王为同型单列和同型多列两类射线,以后者为主,并且多木薄壁细胞而不见生活纤维;四合本叶表皮的角质膜薄。密度丁字毛,气孔极下陷,而霸王叶表皮角质膜厚,无表皮毛,气孔下陷较小;此外,四合木基本组织中富含簇品细胞,茎中具特殊的油细胞,而霸王中不存在。这些差异特征支持一些分类工作者把四合木属从霸王亚科分出,新成立四合木亚科(Tetranenoideae Maet S. Z. zhang)。
基金funded by the Natural Science Foundation of Inner Mongolia
文摘Techniques have been developed for the vegetative propagation of Tetraena mongolica,a rare and endangered species endemic to the western Ordos Plateau in the northcentral portion of China.The purpose of the study was to investigate the rooting characteris-tics of the plant species from the aspects of length and ages of cuttings,external hormone concentration,leaf retention,cutting orientations,and cutting positions.The results obtained from the experiments indicated that the rooting ratio of 2-year or 3-year old cuttings was larger than more than of 4-year old cuttings.The influence of external hormone concentration on rooting was ob-vious;the rooting ratio of cuttings was increased by external hormone treatment,especially when treated by ABT1(ABT No.1 Rooting Powder) 50 mg/L for 3 hours,in which case,the rooting ratio reached 91 percent.Leaf retention influenced rooting sig-nificantly;the rooting rate of cuttings became greater as the leaf retention increased.There was no significant difference in rooting capability between south and north orientations of the ortets.The rooting ratio of the cuttings obtained from the distal portions of shoots was significantly larger than those obtained from the middle and the basal portions of the shoots.On day three after treat-ment,calluses started appearing at the incisions of some cuttings dipped in 500 mg/L IAA(indole acetic acid).Most cuttings were healed or swelled,and 6 percent of cuttings rooted on day 6 after treatment.Higher rooting period occurred 7-10 days after the experiment was set up.
基金supported by the National Natural Science Foundation of China (30770224)the National Basic Research Program of China (2011CBA00901)
文摘Two cDNAs encoding putative type 1 acyl-CoA： diacylglycerol acyltransferases （DGAT1, EC 2.3.1.20）, were cloned from Tetraena mongolica Maxim., an extreme xerophyte with high oil content in the stems. The 1,488-bp and 1,485-bp of the open reading frame （ORF） of the two cDNAs, designated as TmDGAT1a and TmDGAT1b, were both predicted to encode proteins of 495 and 494 amino acids, respectively. Southern blot analysis revealed that TmDGAT1a and TmDGAT1b both had low copy numbers in the T. mongolica genome. In addition to ubiquitous expression with different intensity in different tissues, including stems, leaves and roots, TmDGAT1a and TmDGAT1b, were found to be strongly induced by high salinity, drought and osmotic stress, resulting in a remarkable increase of triacylglycerol （TAG） accumulation in T. mongolica plantlets. TmDGAT1a and TmDGAT1b activities were confirmed in the yeast H1246 quadruple mutant （DGA1, LRO1, ARE1, ARE2） by restoring DGAT activity of the mutant host to produce TAG. Overexpression of TmDGAT1a and TmDGAT1b in soybean hairy roots as well as in T. mongolica calli both resulted in an increase in oil content （ranging from 37% to 108%）, accompanied by altered fatty acid profiles.
基金supported by The Natural Science Foundation of Inner Mongolia (No. 200711020606 and Grant No. 20080404zd14)The Key Project of Sciences Technology of the Chinese Ministry of Education (No.209022)
文摘This paper uses Landsat TM images, GIS technology, Digital Elevation and Habitat Assessment Models to assess the habitat suitability of the endangered plant Tetraena mongolica in western Ordos Plateau of China by selecting terrain, soil, climate, and human activity factors as assessment indices. The results are as follows： natural factors such as climate and terrain are not restrictive factors for the survival and development of T. mongolica in the research region, whereas human activity causes habitat quality of T. mongolica to change intensively in quantity and distribution. The area of less suitable habitat increased by 23.87 km2 compared to potential habitat suitability. Thus, in some areas, human activity may be a key factor causing the endangerment of T. mongolica. There were obvious differences of potential and practical habitat suitability between different habitat regions in the study area. The habitat quality was better in Wujiamiao, Dishan and Qipanjing regions, and worse in Wuda and Qianlishan regions.
基金supported by the National Natural Science Foundation of China(Grant No.41967009)the Inner Mongolia Autonomous Region Talent Development Fund(Inner Mongolia Autonomous Region Human Resources and Social Security Office issued[2020]98)。
文摘Phytogenic mounds(nebkhas)formed by shrubs are a common phenomenon in arid and semiarid areas.The formation of nebkhas is accompanied by the appearance of the fertile island effect.Quantitative evaluation of the shrub sand compost island effect is a key link in preventing soil erosion and nutrient loss.This study took the typical shrub Tetraena mongolica in desert areas as the research object and quantified the sand-trapping capacity of the shrub.We revealed the influence of sediment texture and volumetric soil water content on fertile islands during the development of T.mongolica nebkhas.The results showed that(1)the single shrub intercepted large amounts of sediments due to the high density of branches of T.mongolica,forming nebkhas that were positively correlated with the shrub size.(2)The overall soil nutrient content below the shrub was greater than the soil nutrient content outside the shrub,forming a typical fertile island effect.The soil organic carbon(SOC),alkaline hydrolytic nitrogen(AHN),available phosphorus(AP),and available K(AK)content all increased gradually with increasing nebkha volume.Compared with the deep soil of nebkhas,the nutrient content of the surface soil was generally higher.(3)There was a positive correlation between the volumetric water content and nutrient content in nebkhas.(4)The semi-ellipsoid shape of T.mongolica enabled it to intercept large amounts of coarse-grained material.Fine sand(100–250μm)was the main particle size in the sediment aggregates inside the nebkhas.The fine sand content generally increased with increasing shrub size.Redundancy analysis(RDA)revealed that the fine sand content of the nebkha sediments had a strong positive correlation with the soil nutrient content.This paper provides an example for evaluating the fertile island effect during the deposition process of nebkhas in the desert transition zone.
