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31.
Evans Mutegi Amy L. Stottlemyer Allison A. Snow Patricia M. Sweeney 《Restoration Ecology》2014,22(2):223-231
Switchgrass (Panicum virgatum L.) is a dominant, perennial C4 grass of North American tallgrass prairies with cultivars that are widely used in grassland restoration, pastures, and landscaping. However, these cultivars may be genetically dissimilar to small, remnant populations, raising concerns about altered genetic composition of native populations through gene flow. To address this issue on a local scale in Ohio and Illinois, we used microsatellite markers to characterize genetic diversity and differentiation of 10 remnant prairie populations (5 in each state) and 8 common cultivars. The bulk of genetic variation was found to reside within rather than among wild populations, consistent with the outcrossing breeding system of switchgrass. Genetic diversity was similar among the remnant populations despite large differences in area (approximately 2–2,590 ha), highlighting the importance of small native populations as reservoirs of variation and potential seed sources for prairie restoration. Cultivars generally had similar levels of variation to the wild populations, but we found clear genetic dissimilarity between wild and cultivated gene pools (especially for Kanlow, but also Trailblazer, Blackwell, Dacotah, Summer, and Sunburst cultivars). This suggests that using cultivars in local prairie restoration efforts may alter the genetic composition of wild populations. Whether such changes are deemed as negative depends on the cultivar under consideration and specific conservation goals for preserving native switchgrass populations. Patterns of genetic variation in remnant prairie populations and potential cultivar sources can be used to develop guidelines for restoration as well as future planting of cultivars for biofuels. 相似文献
32.
Depletion of macro-nutrients from rhizosphere soil solution by juvenile corn,cottonwood, and switchgrass plants 总被引:7,自引:0,他引:7
In situ sampling of rhizosphere solution chemistry is an important step in improving our understanding of soil solution nutrient
dynamics. Improved understanding will enhance our ability to model nutrient dynamics and on a broader scale, to develop effective
buffers to minimize nutrient movement to surface waters. However, only limited attention has been focused on the spatial heterogeneity
and temporal dynamics of rhizosphere solution, and still less is known about how rhizosphere solution chemistry varies among
plant species. Nutrients in rhizosphere soil solution and changes in root morphology of juvenile corn (Zea mays L. cv. Stine 2250), cottonwood (Populus deltoids L.), and switchgrass (Panicum virgatum L.) were monitored using mini-rhizotron technology. Plants were grown for 10 days in a fine-silty, mixed, superactive, mesic
Cumulic Hapludoll (Kennebec series). Micro-samples (100–200 μL) of rhizosphere and bulk soil solution were collected at 24-h
intervals at a tension of −100 kPa and analyzed for P, K, Ca, and Mg concentration using Capillary Electrophoresis techniques.
Plants were harvested at the end of the 10-day period, and tissue digests analyzed for nutrient content by Inductively Coupled
Plasma Spectroscopy. Corn plants produced roots that were 1.3 times longer than those of cottonwood, and 11.7 times longer
than those of switchgrass. Similar trends were observed in number of root tips and root surface area. At the end of 10 days,
rhizosphere solution P and K concentrations in the immediate vicinity of the roots (<1 mm) decreased by approximating 24 and
8% for corn, and 15 and 5% for cottonwood. A rhizosphere effect was not found for switchgrass. After correction for initial
plant nutrient content, corn shoot P, K, and Mg were respectively 385, 132, and 163% higher than cottonwood and 66, 37, and
10% higher than switchgrass. Cottonwood shoot Ca concentration, however, was 68 to 133% higher than that of corn or switchgrass.
There was no difference in root P concentration among the three species. Nutrient accumulation efficiency (μg nutrient mm−1 root length) of cottonwood was 26 to 242% higher for P, 25 to 325% higher for Ca, and 41 to 253% higher for Mg than those
of corn and switchgrass. However, K accumulation efficiency of corn was four to five times higher than that of the cottonwood
and switchgrass. Nutrient utilization efficiency (mg of dry weight produced per mg nutrient uptake) of P, K, and Mg was higher
in cottonwood than in corn and switchgrass. These differences are element-specific and depend on root production and morphology
as well as plant nutrient status. From a practical perspective, the results of this study indicate that potentially significant
differences in rhizosphere solution chemistry can develop quickly. Results also indicate that cottonwood would be an effective
species to slow the loss of nutrients in buffer settings.
An erratum to this article can be found at 相似文献
33.
Ye Xia Eliana Greissworth Curtis Mucci Mark A. Williams Seth De Bolt 《Global Change Biology Bioenergy》2013,5(6):674-682
Switchgrass (Panicum virgatum L.) is a perennial warm season grass that is native to the plains of North America and is widely grown as a forage, bioenergy or groundcover crop. Despite its importance, a bottleneck in switchgrass production is poor seedling vigor, which as a perennial crop represents an important time for management. Herein, data identify a suite of culturable bacterial microflora extracted from switchgrass, and show their capability to influence host plant growth and development. A total of 307 bacterial isolates were cultured and isolated from surface sterilized switchgrass biomass and sequence identified into 76 strains (subspecies classification), 36 species and 5 phyla. Approximately 58% of bacterial strains, when reintroduced into surface‐sterilized switchgrass seeds, were documented to increase lamina length (cm from base to tip after 60 days growth) relative to uninoculated controls. Ecologically, Phylum Firmicutes was the most abundant bacterial classification and encompassed 75% of all isolates. Although the culturable bacterial community studies herein represent an unknown and assumedly minor proportion of the total microbiome, by focusing on culturable bacteria, we delineate functional feedback between the presence of isolated bacteria and switchgrass seedling growth. 相似文献
34.
水稻与大黍不对称体细胞杂交再生植株 总被引:12,自引:0,他引:12
采用PEG(聚乙二醇)融合法,诱导水稻(Oryza sativa L.)原生质体与无融合生殖大黍(Panicummaximum Jacq.)原生质体融合,经过融合体筛选、培养,成功地获得了再生植株并移栽成活。在融合前,水稻原生质体经过2.5mmol/L碘乙酰胺(IOA)在室温(22~25℃)条件下处理15min,大黍原生质体经过60Kr软X射线照射处理。对获得的28株融合再生植株进行初步检查发现,在花器官形态、结构及生殖特性上与对照亲本水稻植株有显著的差异,出现多花药(一朵颖花具7~11枚甚至13枝花药)、多胚珠(1个子房内有2~3个胚珠)及“多胚囊”(1个胚珠内有2个以上类似胚囊的结构)等现象。雌、雄性育性显著降低或完全不育,仅有5株能够少量结实,I-KI溶液着色的花粉从0至68%不等。细胞胚胎学检查表明不能结实的植株雌性均不育,即不能分化出正常的胚囊结构。 相似文献
35.
36.
本文以一种C4植物——黍子(Panicum miliaceum)为材料,在白光、红光、蓝光、远红光和黑暗5种不同条件下培养黍子幼苗,叶片采收后用于叶绿素积累、叶绿体吸收光谱、叶绿体低温荧光发射光谱和高分子量cpRNA积累的测定以及psbA基因的Northern Blot分析。结果表明:白光、红光和蓝光下生长的黍子,它们的叶绿体都有功能完善的光合系统;而远红光下生长的黍子,已有光系统Ⅱ的发射峰,只是强度和波长都与白光、红光和蓝光下的有所不同;不同光质促进叶绿素积累和高分子量cpRNA积累的效率是平行的,其中红光较蓝光和远红光有效,而复合光(白光)的作用效果最好。当以白光诱导的积累量为100%时,可以分别求出不同光质诱导叶绿素积累和高分子量cpRNA积累的相对量,结果表明,高分子量cpRNA的积累对光的依赖性要比叶绿素积累对光的依赖性大得多。psbA基因的Northern Blot分析表明,不同光质下psbA转录物的积累与高分子量cpRNA的积累是一致的。据此我们推测,在黍子叶绿体的光诱导发育过程中,psbA的转录过程可能不受光信号的直接调控,而是受叶绿体整体发育状态的控制。 相似文献
37.
Tezera W. Wolabu Yanqi Wu Zeng‐Yu Wang Million Tadege 《Plant, cell & environment》2016,39(10):2158-2171
Switchgrass (Panicum virgatum L.), a perennial warm season bunchgrass native to North America, has been a target in the U.S. as a renewable bioenergy crop because of its ability to produce moderate to high biomass yield on marginal soils. Delaying flowering can increase vegetative biomass production by allowing prolonged growth before switching to the reproductive phase. Despite the identification of flowering time as a biomass trait in switchgrass, the molecular regulatory factors involved in controlling floral transition are poorly understood. Here we identified PvFT1, PvAPL1‐3 and PvSL1, 2 as key flowering regulators required from floral transition initiation to development of floral organs. PvFT1 expression in leaves is developmentally regulated peaking at the time of floral transition, and diurnally regulated with peak at approximately 2 h into the dark period. Ectopic expression of PvFT1 in Arabidopsis, Brachypodium and switchgrass led to extremely early flowering, and activation of FT downstream target genes, confirming that it is a strong activator of flowering in switchgrass. Ectopic expression of PvAPL1‐3 and PvSL1, 2 in Arabidopsis also activated early flowering with distinct floral organ phenotypes. Our results suggest that switchgrass has conserved flowering pathway regulators similar to Arabidopsis and rice. 相似文献
38.
Abstract Ultrastructural and physiological characteristics of the C3-C4 intermediate Neurachne minor S. T. Blake (Poaceae) are compared with those of C3 and C4 relatives, and C3-C4Panicum milioides Nees ex Trin. N. minor consistently exhibits very low CO2 compensation points (τ: 1.0, usually 0.3–0.6 Pa) yet has C3-like δ13C values. CO2 assimilation rates (A) respond like those of C3 plants to a decrease in O2 partial pressure (2 × 104–1.9 × 103 Pa) at ambient CO2 levels, but this response is progressively attenuated until negligible at very low CO2. By contrast, other species of the Neurachneae are clearly either C4 (two spp.) or C3 (seven spp.). For plants grown and measured at different photon flux densities (PFDs), τ for N. minor and P. milioides increases from 0.5 to 1.0, and from 1.0 to 2.1 Pa, respectively, as PFD is decreased from 1860 to 460 μmol m?2s?1. In N. minor, the O2 response of τ is either biphasic as in P. milioides, but much diminished and with a higher transition point, or is very C4-like. As in C4 relatives, inner sheath cells contain numerous chloroplasts. Their walls possess a suberized lamella, which may make them more CO2-tight than bundle sheath cells of P. milioides, contributing to the almost C4-like τ characteristics of N. minor. The biochemical basis of C3-C4 intermediacy is considered. 相似文献
39.
Summary The influence of seasonal variation on nitrogenase (N2-ase) activity of undisturbed soil-plant cores ofPanicum maximum var.trichoglume was measured using the C2H2 reduction assay.
The largest N2-ase activity in the field, 14.7 g N ha−1 day−1, occurred in spring when soil moisture was high, soil temperature was low and nitrogenous fertiliser influence was at a minimum.
The potential N2-ase activity of the cores, measured under controlled conditions, reached a maximum of 27.2 g N ha−1 day−1 and averaged 26.3 g N ha−1 day−1 over the 14 month sampling period.
N2-ase activity was positively correlated (P=0.05) with field soil moisture and negatively correlated with field soil temperature (r=0.59 and −0.78 respectively). Multiple
regression showed that 69% of the variation of N2-ase activity in the field was associated with the combined effects of soil moisture and soil temperature.
Nitrogen fixing bacteria were isolated from the roots ofP. maximum and based upon morphology, biochemical tests and fluorescent antibody reaction, were found to be closely related toAzospirillum lipoferum. 相似文献
40.
W. D. BOWMAN EPO 《Plant, cell & environment》1991,14(3):295-301
Abstract. The growth and photosynthetic responses to high and low N nutrition were measured in 2 NADP-malic enzyme and 4 NAD-malic enzyme C4 subtype Panicum species to evaluate whether differences in C4 photosynthetic biochemistry result in differences in the N requirement for growth. All species had lower biomass production, photosynthesis rates, and shoot N concentrations at low N, and no consistent differences between the C4 subtypes were apparent. The assimilation rates (biomass accumulated over the period of growth) for the NADP-malic enzyme species were higher than the NAD-malic enzyme species at high N but not at low N. When assimilation rates were evaluated on a shoot N basis a higher N-use-efficiency was found for the NADP-malic enzyme species at high N. Thus the NADP-malic enzyme Panicum species had a greater amount of growth for a given shoot N concentration, but only above a certain level of shoot N concentrations. 相似文献