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Plant growth and soil microbial community structure of legumes and grasses grown in monoculture or mixture

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Journal of Environmental Sciences 2008年第10期20卷 1231-1237页

作者： MARSCHNER Petra Soil and Land System School of Earth and Environmental Sciences The University of AdelaideAdelaide 5005 Australia

A greenhouse pot experiment was conducted to investigate the in?uence of soil moisture content on plant growth and the rhizosphere microbial community structure of four plant species (white clover, alfalfa, sudan grass, tall fescue), grown individually or in a mixture. The soil moisture content was adjusted to 55% or 80% water holding capacity (WHC). The results indicated that the total plant biomass of one pot was lower at 55% WHC. At a given soil moisture, the total plant biomass of white clover and tall ...

关键词： legumes grasses the Chinese Loess Plateau microbial communities phospholipid fatty acid (PLFA)

Duplication and Divergence of Floral MADS-Box Genes in grasses： Evidence for the Generation and Modification of Novel Regulators

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Journal of Integrative Plant Biology 2007年第6期49卷 927-939页

作者： Guixia Xu Hongzhi Kong State Key Laboratory of Systematic and Evolutionary Botany Institute of Botany the Chinese Academy of Sciences Beijing 100093 China Graduate University of the Chinese Academy of Sciences Beijing 100039 China

The process of flowering is controlled by a hierarchy of floral genes that act as flowering time genes, inflorescence/floral meristem Identity genes, and/or floral organ-identity genes. The most important and well-characterized floral genes are those that belong to the MADS-box family of transcription factors. Compelling evidence suggests that floral MADS-box genes have experienced a few large-scale duplication events. In particular, the precore eudicot duplication events have been considered to correlate with the emergence and diversification of core eudicots. Duplication of floral MADS-box genes has also been documented in monocots, particularly In grasses, although a systematic study is lacking. In the present study, by conducting extensive phylogenetlc analyses, we identified pre-Poaceae gene duplication events in each of the AP1, P1, AG, AGL11, AGL2/3/4, and AGL9gene lineages. Comparative genomic studies further indicated that some of these duplications actually resulted from the genome doubling event that occurred 66-70 million years ago （MYA）. In addition, we found that after gene duplication, exonization （of intron sequences） and pseudoexonization （of exon sequences） have contributed to the divergence of duplicate genes in sequence structure and, possibly, gene function.

关键词： divergence Oryza sativa gene duplication genome doubling event grasses MADS-box genes.

Soil Depth and Changes in Dry Mass and Competitive Intensity of Two C4grasses

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American Journal of Plant Sciences 2014年第1期5卷 138-147页

作者： J. K. Bush O. W. Van Auken Department of Biology University of Texas at San Antonio San Antonio USA Environmental Science College of Sciences University of Texas at San Antonio San Antonio USA

The presence of grassland biomes and species cannot be predicted by examining bottom up causes such as precipitation and temperature. Top down causes including herbivory and fire seem to be major controlling aspects with other factors secondary. We examined soil depth and competitive ability of two North American C4 grasses in a greenhouse experiment. Changes in dry mass were determined and competitive intensity was calculated for both species. Species were grown separately or together in pots 30, 90, or 180 cm deep. When grown in monoculture, Schizachyrium scoparium total and belowground dry mass increased from the 30 to 90 cm depth, with no further significant increase from 90 to 180 cm. Aboveground dry mass did not increase significantly with depth. Total dry mass of Buchloe dactyloides increased significantly with depth when grown in monoculture. Aboveground dry mass increased from 30 to 90 cm depth but not from 90 to 180 cm. Belowground dry mass of B. dactyloides did not increase significantly with depth. In 180 cm pots, 53% of S. scoparium root dry mass was in the top 30 cm;74% of B. dactyloides root dry mass was in the top 30 cm. Roots of B. dactyloides were not found deeper than 90 cm. Aboveground dry mass of S. scoparium was not different in mixture or monoculture at any depth. Buchloe dactyloides aboveground dry mass in mixture was significantly lower than monoculture at the 30 cm depth, but not at 90 or 180 cm. The greatest competitive intensity was in the shallow soil pots. Soil depth could partially explain mosaics found in C4 grasslands where both species were found together with S. scoparium on deeper soils and B. dactyloides on shallower soils.

关键词： C4 grasses Buffalo Grass Little Bluestem Dry Mass Depth Competitive Intensity Semi-Arid Grasslands

Isolation and Identification of Bacterial Endophytes from grasses along the Oregon Coast

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American Journal of Plant Sciences 2017年第3期8卷 574-601页

作者： James E. Dombrowski Vicky G. Hollenbeck Ruth C. Martin USDA ARS Forage Seed and Cereal Research Unit Corvallis Oregon USA

Bacterial endophytes have been shown to improve abiotic and biotic stress responses in plants. Plants growing under harsh conditions along the Oregon Coast could contain bacterial endophytes that improve persistence and growth of grasses in this environment. Thirty-four plants consisting of eight different species were collected along the Oregon coast from four different sites. Bacterial endophytes were isolated from root crown, stem and leaf tissues. A portion of the 16S rRNA ITS regions of each isolate was amplified, sequenced, and used to perform a BLAST search against the nucleotide database collection at National Center for Biotechnology Information. One-hundred and thirty-three different bacterial isolates, ninety-four of which were unique, representing thirty-six different taxonomic groups were found. Over 50% of the total bacteria isolates were in just five taxonomic groups. Pseudomonads were the most predominant bacteria isolated, making up 20.3% of the total isolates, followed by Curtobacterium and Microbacterium, each at 8.2%, Bacillus at 7.5% and Xanthomomas at 6%. Forty-seven percent (17 of 36) of the taxonomic groups contained only a single isolate. Fourteen bacterial isolates from five taxonomic groups, nine of which were from the genus Pseudomonas, were found to have 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity, an enzyme associated with improving plant growth under stress. These newly discovered bacterial endophytes will be a valuable biological resource to develop approaches to increase the yield and adaptability of grasses and other crops grown in diverse environments and to meet the challenges associated with an unpredictable climate.

关键词： Endophyte grasses ACC Deaminase Bacteria Abiotic Stress Salt Stress

Observations of Spring Hard Freeze Injury to C4Perennial grasses Native to the Great Plains, USA

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American Journal of Plant Sciences 2019年第5期10卷 723-729页

作者： Rob Mitchell Daren Redfearn Wheat Sorghum and Forage Research Unit USDA-ARS Lincoln Nebraska USA Department of Agronomy and Horticulture University of Nebraska Lincoln Nebraska USA

The native prairies of the Great Plains USA are dominated by perennial C4 grasses like switchgrass (Panicum virgatum) and big bluestem (Andropogon gerardii). Spring hard freeze injury to C4 perennial grasses is rare but information is lacking in the literature. Our objective was to document effects of spring hard freeze damage to C4 perennial grasses native to the Great Plains USA. On 2 May at 24:00 pm, air temperature near Mead, Nebraska was below freezing and remained below freezing until 8:00 am on 3 May, with a minimum air temperature of -2.8°C. Based on 50-year of weather data for this site, a minimum threshold temperature of 0°C on or after 3 May occurred 16 times, but a minimum threshold temperature of -2.8°C on or after 3 May occurred only twice. Grass tillers were visually evaluated to determine extent of freeze damage. The terminal 3- to 5-cm of the leaf lamina was blackened 4-d after freezing and had complete browning, rolling, and desiccation 14-d after freezing. Tiller survival was not negatively affected by the freezing temperatures in May 2004. As the growing season progressed, all agronomic and livestock responses were within normal ranges for these C4 grasses. This is the first field report of multiple C4 prairie grass species responses to a spring hard freeze following significant spring growth. Plant recovery to this late-spring hard freeze demonstrates the ecological resilience of these C4 prairie grasses. These rare spring hard freezes had short-term impacts on C4 grasses but did not negatively impact agronomic performance for forage or bioenergy later in the growing season.

关键词： C4 Perennial grasses Spring Hard Freeze

Prediction of the Distribution of Perennial Cultivated grasses in the Northwest Sichuan Plateau, China under Climate Change

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Journal of Geoscience and Environment Protection 2019年第10期7卷 95-111页

作者： Bin Guo San Wang Chao Chen Mingtian Wang Tingting Li Chengdu/Heavy Rain and Drought-Flood Disasters in Plateau and Basin Key Laboratory of Sichuan Province Institute of Plateau Meteorology China Meteorological Administration Chengdu China Aba Prefecture Meteorological Administration Maerkang China Provincial Key Laboratory of Water-Saving Agriculture in Hill Areas of Southern China Chengdu China Sichuan Meteorlogical Observatory Chengdu China State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry Institute of Atmospheric Physics Chinese Academy of Science Beijing China

In order to determine the threshold and potential distribution of climatic conditions for perennial cultivated grasses in the Northwest plateau of Sichuan, China, the niche model is used to simulate the main climatic factors affecting the distribution of perennial cultivated grasses, and to predict the current and future climate change prospects. The results show that: 1) Wet index, accumulated temperature, isothermal, and annual average temperature range are the four major climatic factors affecting the distribution of perennial cultivated grasses in the Northwest Sichuan Plateau. 2) Model training and prediction data can be achieved well under the appropriate range of major climatic factors. 3) Under the background of climate warming, from now to 2080, the potential distribution of perennial cultivated grasses in the Northwest plateau of Sichuan, China will increase. The study aims to provide scientific decision-making basis for maintaining grassland ecosystem stability and promoting desertification management and even industrial restructuring of agriculture and animal husbandry.

关键词： Clmatei Change MaxEnt Model Dominant Factor Perennial Cultivated grasses Northwest Sichuan Plateau

Ecological Study of Two grasses: Cenchrus ciliarisand Digitaria commutateEndangered Autochthonous of the Dry Zone of Tunisia

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Open Journal of Forestry 2014年第4期4卷 349-362页

作者： Imen Dhib Abdessalem Abdessamad Mustapha Ksontini Ali Ferchichi Laboratoire d’arido culture et culture oasiènne Institute of the Dry Regions Medenine Route du Djorf Km Medenine Tunisie Laboratoire de sylviculture forstière National Institute of Searches in Rural Genius Water and Forest Ariana Tunis

The Saharian ecosystems present an important intensity of rising sensitization to: Erosion, and desertification whose impacts are irreversible. On the one hand, the weakness of the yield and the poverty of soil lead to a limited biodiversity. In addition to these difficulties, hydra is the main cause of the rarification of certain pastoral species such as Cenchrus ciliaris and Digitaria commutata. The ecological study underlines a distribution of these species which are very dependent on water resources in the dry regions of Tunisia. The bioclimatic (temperature, pluviometry) variations lead to modifications to these species from one area to another which are translated through several parameters. Concerning the number of bundles, the difference is important. The national park of Bouhedma records the highest number, compared with Bni khdach, Jerba, Khanguit aicha and Matmata respectively. The variation inter-site of study also is considerable by the study of the morphological parameters (height, number and length of leaves by bundle, number of ear) whose bundles of the national park Bouhedma occupy the first class.

关键词： Ecological Study grasses Endangered Dry Zone Of Tunisia

Phytoliths of common grasses in the coastal environments of southeastern USA

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Phytoliths of common grasses in the coastal environments of ...

Morphological variations of lobate phytoliths from grasses in China and the south-eastern United States

中国科学院地质与地球物理研究所2003学术年会

作者： Kam-biu Liu Department of Geography and Anthropology Louisiana State UniversityBaton RougeLA 70803USA

Thirty-four grass species were collected for phytolith analysis from a variety of coastal environments in the southeastern USA (***,and Louisiana),including salt marshes,freshwater/brackish marshes,pine/oak forests,maritime hardwood forests,and sand *** produced by these modern grasses include a large diversity of shapes and *** propose a preliminary relationship between modern coastal plant communities and their predominant phytolith *** dominant grasses of coastal sand dunes,such as Uniola *** primarily flat tower and two-horned tower *** saddle ellipsoid phytoliths are mainly produced by Spartina *** most common plant in coastal salt *** and spool horned tower phytoliths are common in brackish marsh *** from interdune meadow produce primarily dumbbell *** well as small cross and Cyperaceae-type *** results provide a basis for the interpretation of fossil phytolith assemblages and the reconstruction of coastal environmental changes. (?)2003 Elsevier *** rights reserved.

关键词： phytoliths silica bodies grasses microfossils coastal environments Quaternary southeastern USA

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Morphological variations of lobate phytoliths from grasses i...