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Sherwin Carlquist - One of the best experts on this subject based on the ideXlab platform.
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Distinctive tracheid microstructure in stems of Victoria and Euryale (Nymphaeaceae).
Botanical Journal of the Linnean Society, 2009Co-Authors: Sherwin Carlquist, Edward L. SchneiderAbstract:Scanning electron microscopy (SEM) photographs of thick sections from liquid-preserved stems of Victoria cruziana and Euryale ferox show accretions of coarse fibrils on pit membranes of tracheids. The first-deposited fibrils are randomly orientated; on top of them (facing the tracheid lumina) are axially orientated coarse fibrils. The two systems are interconnected. Axially orientated fibrils were more extensively observed in Euryale than in Victoria and tips of fibrils in Euryale extend over the pit apertures onto secondary wall surfaces. Tracheid–parenchyma interfaces bear rudimentary coarse fibrils on the tracheid side. End walls of Victoria tracheids have highly porose pit membranes, thinner and less complex than those of the lateral intertracheid walls. The structures reported in Victoria and Euryale are consistent with those concurrently reported for stems of other Nymphaeaceae. Although also present in Cabombaceae, the coarse fibrils are otherwise not reported for stems of angiosperms and are not yet reported in roots of any species. Pit membrane remnants in perforation plates of various woody Dicotyledons represent a nonhomologous phenomenon. The accretions of coarse fibrils in stem tracheids of Nymphaeaceae do not appear to enhance conduction, although they do contain porosities interconnecting tracheids. Removal of pit membrane remnants from perforation plates of primitive Dicotyledon woods by hydrolysis does, on the contrary, suggest conduction enhancement. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 159, 52–57.
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wood and stem anatomy of woody amaranthaceae s s ecology systematics and the problems of defining rays in Dicotyledons
Botanical Journal of the Linnean Society, 2003Co-Authors: Sherwin CarlquistAbstract:Wood and stem anatomy is studied for seven species of six genera (root anatomy also reported for one species) of Amaranthaceae s.s. Quantitative data on vessels correlate closely with relative xeromorphy of respective species, agreeing with values reported for Dicotyledons without successive cambia in comparable habitats. Libriform fibre abundance increases and vessel diameter decreases as stems and roots of the annual Amaranthus caudatus mature. Long, thick-walled fibres in Bosea yervamora may be related to the upright nature of elongate semi-climbing stems. Non-bordered or minutely bordered perforation plates characterize Amaranthaceae, as they do most other Caryophyllales. Amaranthaceae have idioblastic cells containing druses, rhomboidal crystals or crystal sand: these forms intergrade and seem closely related. Rays are present in secondary xylem of the Amaranthaceae studied. Cells intermediate between ray cells and libriform fibres occur in Charpentiera elliptica. Degrees of diversity in rays and reports of raylessness in Amaranthaceae induce discussion of definition and identification of rays in Dicotyledons; some sources recognize both rays and radial plates of conjunctive tissue in Amaranthaceae. The action of successive cambia is described: lateral meristem periclinal divisions produce secondary cortex externally, conjunctive tissue internally and yield vascular cambia as well. Vascular cambia produce secondary phloem and secondary xylem, in both ray and fascicular zones, as in a Dicotyledon with a single cambium. Identification of meristem activity and appreciation of varied ray manifestations are essential in understanding the ontogeny of stems in Amaranthaceae (which have recently been united with Chenopodiaceae). © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society, 2003, 143, 1–19.
M.w.a. Verstegen - One of the best experts on this subject based on the ideXlab platform.
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Fermentation of the endosperm cell walls of monocotyledon and Dicotyledon plant species by faecal microbes from pigs the relationship between cell wall characteristics and fermentability.
Animal Feed Science and Technology, 2000Co-Authors: Harmen Van Laar, Seerp Tamminga, Barbara A. Williams, M.w.a. VerstegenAbstract:Cell walls from the endosperm of four monocotyledons (maize, wheat, rye, and rice) and four Dicotyledons (soya bean, lupin, faba bean, and pea) seeds were studied to relate cell wall composition and structure with fermentation characteristics. Cell wall material was isolated from the endosperm of the mono- and Dicotyledons. The fermentation characteristics of isolated cell walls from mono- and Dicotyledons were analysed in two separate in vitro gas production experiments. At 0, 12, 24, 36, 48, and 144 h of fermentation, fermentation was stopped in selected bottles to analyse VFA production (144 h only) and sugar degradation patterns. The relationship between cell wall characteristics (composition, particle size) and fermentation characteristics (half-time of gas production and maximal rate of substrate degradation) was analysed using linear regression. For the monocotyledon cell walls, the rate of substrate degradation was decreased by increasing particle size of the cell walls, a clear effect of cell wall composition on fermentation characteristics could not be determined, though this might have been obscured by the differences in particle size. During fermentation of the monocotyledon cell wall, arabinoxylans (arabinose and xylose) and cellulose (glucose) appeared to be degraded simultaneously. For the Dicotyledon cell walls, an increase in total sugar content decreased the half-time of gas production, though total sugar content was probably confounded with the crude protein content. During fermentation of the Dicotyledon cell wall, pectins or pectin-related sugars (galactose, arabinose, uronic acids) appeared to be degraded faster than cellulose, whereas for the monocotyledon cell walls, arabinoxylans and cellulose were degraded simultaneously. The differences in cell wall fermentation and sugar degradation pattern between monocotyledon and Dicotyledon cell walls are discussed in relation to differences in cell wall architecture.
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Fermentation of the endosperm cell walls of monocotyledon and Dicotyledon plant species by faecal microbes from pigs
Animal Feed Science and Technology, 2000Co-Authors: Harmen Van Laar, Seerp Tamminga, Barbara A. Williams, M.w.a. VerstegenAbstract:Cell walls from the endosperm of four monocotyledons (maize, wheat, rye, and rice) and four Dicotyledons (soya bean, lupin, faba bean, and pea) seeds were studied to relate cell wall composition and structure with fermentation characteristics. Cell wall material was isolated from the endosperm of the mono- and Dicotyledons. The fermentation characteristics of isolated cell walls from mono- and Dicotyledons were analysed in two separate in vitro gas production experiments. At 0, 12, 24, 36, 48, and 144h of fermentation, fermentation was stopped in selected bottles to analyse VFA production (144h only) and sugar degradation patterns. The relationship between cell wall characteristics (composition, particle size) and fermentation characteristics (half-time of gas production and maximal rate of substrate degradation) was analysed using linear regression. For the monocotyledon cell walls, the rate of substrate degradation was decreased by increasing particle size of the cell walls, a clear effect of cell wall composition on fermentation characteristics could not be determined, though this might have been obscured by the differences in particle size. During fermentation of the monocotyledon cell wall, arabinoxylans (arabinose and xylose) and cellulose (glucose) appeared to be degraded simultaneously. For the Dicotyledon cell walls, an increase in total sugar content decreased the half-time of gas production, though total sugar content was probably confounded with the crude protein content. During fermentation of the Dicotyledon cell wall, pectins or pectin-related sugars (galactose, arabinose, uronic acids) appeared to be degraded faster than cellulose, whereas for the monocotyledon cell walls, arabinoxylans and cellulose were degraded simultaneously. The differences in cell wall fermentation and sugar degradation pattern between monocotyledon and Dicotyledon cell walls are discussed in relation to differences in cell wall architecture
Thomas Curt - One of the best experts on this subject based on the ideXlab platform.
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Competition for water between beech seedlings and surrounding vegetation in different light and vegetation composition conditions
Annals of Forest Science, 2003Co-Authors: Lluis Coll, Bernard Prévosto, Philippe Balandier, Catherine Picon-cochard, Thomas CurtAbstract:To gain a better understanding of beech growth requirements and assess the competition with the surrounding vegetation at two successional stages after agricultural land abandonment, we introduced two-year-old beech seedlings (i) in a recently abandoned meadow (one half weeded) and (ii) in an old meadow colonised by 25-year-old natural Scots pine, with one part thinned to increase light availability at ground level. Beech seedlings presented significantly different stem diameter growth rates according to vegetation composition (grasses or Dicotyledon species) and light availability for both successional stages. Grass species, which developed efficient strategies to extract soil water, competed strongly with beech seedling compared with Dicotyledon species. Water competition led to a strong reduction of beech diameter growth. For a given vegetation composition, increasing light availability improved beech growth.
Michelle Watt - One of the best experts on this subject based on the ideXlab platform.
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Soil conditions and cereal root system architecture: review and considerations for linking Darwin and Weaver
Journal of Experimental Botany, 2013Co-Authors: Sarah Meghan Rich, Michelle WattAbstract:Charles Darwin founded root system architecture research in 1880 when he described a root bending with gravity. Curving, elongating, and branching are the three cellular processes in roots that underlie root architecture. Together they determine the distribution of roots through soil and time, and hence the plants' access to water and nutrients, and anchorage. Most knowledge of these cellular processes comes from seedlings of the model Dicotyledon, Arabidopsis, grown in soil-less conditions with single treatments. Root systems in the field, however, face multiple stimuli that interact with the plant genetics to result in the root system architecture. Here we review how soil conditions influence root system architecture; focusing on cereals. Cereals provide half of human calories, and their root systems differ from those of Dicotyledons. We find that few controlled-environment studies combine more than one soil stimulus and, those that do, highlight the complexity of responses. Most studies are conducted on seedling roots; those on adult roots generally show low correlations to seedling studies. Few field studies report root and soil conditions. Until technologies are available to track root architecture in the field, soil analyses combined with knowledge of the effects of factors on elongation and gravitropism could be ranked to better predict the interaction between genetics and environment (G×E) for a given crop. Understanding how soil conditions regulate root architecture can be effectively used to design soil management and plant genetics that best exploit synergies from G×E of roots.
Harmen Van Laar - One of the best experts on this subject based on the ideXlab platform.
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Fermentation of the endosperm cell walls of monocotyledon and Dicotyledon plant species by faecal microbes from pigs the relationship between cell wall characteristics and fermentability.
Animal Feed Science and Technology, 2000Co-Authors: Harmen Van Laar, Seerp Tamminga, Barbara A. Williams, M.w.a. VerstegenAbstract:Cell walls from the endosperm of four monocotyledons (maize, wheat, rye, and rice) and four Dicotyledons (soya bean, lupin, faba bean, and pea) seeds were studied to relate cell wall composition and structure with fermentation characteristics. Cell wall material was isolated from the endosperm of the mono- and Dicotyledons. The fermentation characteristics of isolated cell walls from mono- and Dicotyledons were analysed in two separate in vitro gas production experiments. At 0, 12, 24, 36, 48, and 144 h of fermentation, fermentation was stopped in selected bottles to analyse VFA production (144 h only) and sugar degradation patterns. The relationship between cell wall characteristics (composition, particle size) and fermentation characteristics (half-time of gas production and maximal rate of substrate degradation) was analysed using linear regression. For the monocotyledon cell walls, the rate of substrate degradation was decreased by increasing particle size of the cell walls, a clear effect of cell wall composition on fermentation characteristics could not be determined, though this might have been obscured by the differences in particle size. During fermentation of the monocotyledon cell wall, arabinoxylans (arabinose and xylose) and cellulose (glucose) appeared to be degraded simultaneously. For the Dicotyledon cell walls, an increase in total sugar content decreased the half-time of gas production, though total sugar content was probably confounded with the crude protein content. During fermentation of the Dicotyledon cell wall, pectins or pectin-related sugars (galactose, arabinose, uronic acids) appeared to be degraded faster than cellulose, whereas for the monocotyledon cell walls, arabinoxylans and cellulose were degraded simultaneously. The differences in cell wall fermentation and sugar degradation pattern between monocotyledon and Dicotyledon cell walls are discussed in relation to differences in cell wall architecture.
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Fermentation of the endosperm cell walls of monocotyledon and Dicotyledon plant species by faecal microbes from pigs
Animal Feed Science and Technology, 2000Co-Authors: Harmen Van Laar, Seerp Tamminga, Barbara A. Williams, M.w.a. VerstegenAbstract:Cell walls from the endosperm of four monocotyledons (maize, wheat, rye, and rice) and four Dicotyledons (soya bean, lupin, faba bean, and pea) seeds were studied to relate cell wall composition and structure with fermentation characteristics. Cell wall material was isolated from the endosperm of the mono- and Dicotyledons. The fermentation characteristics of isolated cell walls from mono- and Dicotyledons were analysed in two separate in vitro gas production experiments. At 0, 12, 24, 36, 48, and 144h of fermentation, fermentation was stopped in selected bottles to analyse VFA production (144h only) and sugar degradation patterns. The relationship between cell wall characteristics (composition, particle size) and fermentation characteristics (half-time of gas production and maximal rate of substrate degradation) was analysed using linear regression. For the monocotyledon cell walls, the rate of substrate degradation was decreased by increasing particle size of the cell walls, a clear effect of cell wall composition on fermentation characteristics could not be determined, though this might have been obscured by the differences in particle size. During fermentation of the monocotyledon cell wall, arabinoxylans (arabinose and xylose) and cellulose (glucose) appeared to be degraded simultaneously. For the Dicotyledon cell walls, an increase in total sugar content decreased the half-time of gas production, though total sugar content was probably confounded with the crude protein content. During fermentation of the Dicotyledon cell wall, pectins or pectin-related sugars (galactose, arabinose, uronic acids) appeared to be degraded faster than cellulose, whereas for the monocotyledon cell walls, arabinoxylans and cellulose were degraded simultaneously. The differences in cell wall fermentation and sugar degradation pattern between monocotyledon and Dicotyledon cell walls are discussed in relation to differences in cell wall architecture