Importance of whole-plant biomass allocation and reproductive timing to habitat differentiation across the North American sunflowers

ln Spring 1993, red oaks (Quercus rubra) were propagated from seed. From June through October, plants were fertilized twice daily with 1.4 liters of 20N–10P–20K water-soluble fertilizer solution at concentrations of 0, 25, 50, 100, 200, or 400 ppm N. Destructive harvests were conducted six times at intervals from June through Dec. 1993. Leaf area, stem height, root length, root area, and dry weights of roots, stem, and leaves of harvested plants were measured and tissue nutrient concentrations were analyzed. There was no relationship between whole-plant N concentration and total plant biomass (r = 0). However, there were some linear relationships between total plant N and total plant biomass for an individual fertilizer treatment. Biomass allocation between root, stems, and leaves was very consistent across all fertilizer levels at any one harvest. Percent total N in roots, stems, and leaves also was fairly consistent across fertilizer levels. This was true at each harvest, except the first two, in which a greater percentage of total N was partitioned to the leaves and a smaller percentage was partitioned to the roots in the high (100, 200, 400 ppm N) fertilizer treatments. Whole-plant K concentrations increased with increasing fertilizer level, but decreased over time. Whole-plant P concentrations increased linearly with whole-plant dry weight in the higher (100, 200, 400 ppm N) fertilizer treatments.

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Rethinking root-shoot growth dynamics

10.1101/2020.06.29.177824 ◽

2020 ◽

Author(s):

David Robinson

Keyword(s):

Growth Rate ◽

Plant Growth ◽

Biomass Allocation ◽

Plant Biomass ◽

Wide Spectrum ◽

Growth Dynamics ◽

Adaptive Allocation ◽

Physiological Properties ◽

Whole Plant ◽

Rates Of Growth

AbstractUsing a simple plant growth model based on the logistic equation I re-evaluate how biomass allocation between roots and shoots articulates dynamically with the rate of whole-plant biomass production. Defined by parameters reflecting lumped physiological properties, the model constrains roots and shoots to grow sigmoidally over time. From those temporal patterns detailed trajectories of allocation and growth rate are reconstructed. Sigmoid growth trajectories of roots and shoots are incompatible with the dominant ‘functional equilibrium’ model of adaptive allocation and growth often used to explain plants’ responses to nutrient shortage and defoliation. Anything that changes the differential rates of growth between roots and shoots will automatically change allocation and, unavoidably, change whole-plant growth rate. Biomass allocation and whole-plant growth rate are not independent traits. Allocation and growth rate have no unique relationship to one another but can vary across a wide spectrum of possible relationships. When root-shoot allocation seems to respond to the environment it is likely to be a secondary illusory consequence of other primary responses such as localised root proliferation in soil or leaf expansion within canopy gaps. Changes in root-shoot allocation cannot themselves compensate directly for an impairment of growth rate caused by an external factor such as nutrient shortage or defoliation; therefore, such changes cannot be ‘adaptive’.‘The reasons are so simple they often escape notice.’ (James 2012, p. 6).

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Effect of pH on xylitol production by Candida species from a prairie cordgrass hydrolysate

Zeitschrift für Naturforschung C ◽

10.1515/znc-2020-0140 ◽

2020 ◽

Vol 75 (11-12) ◽

pp. 489-493

Author(s):

Samatha S. R. Rudrangi ◽

Thomas P. West

Keyword(s):

North American ◽

Plant Biomass ◽

Candida Guilliermondii ◽

Specific Productivity ◽

Xylitol Production ◽

G Cells ◽

The North ◽

Prairie Grass ◽

Prairie Cordgrass ◽

North American Prairie

AbstractUsing hydrolysates of the North American prairie grass prairie cordgrass buffered at pH 4.5, 5.0, 5.5 or 6.0, xylitol production, xylitol yield, cell biomass production and productivity were investigated for three strains of yeast Candida. Of the three strains, the highest xylitol concentration of 20.19 g xylitol (g xylose consumed)−1 and yield of 0.89 g xylitol (g xylose consumed)−1 were produced by Candida mogi ATCC 18364 when grown for 120 h at 30° C on the pH 5.5-buffered hydrolysate-containing medium. The highest biomass level being 7.7 g cells (kg biomass)−1 was observed to be synthesized by Candida guilliermondii ATCC 201935 after 120 h of growth at 30° C on a pH 5.5-buffered hydrolysate-containing medium. The highest xylitol specific productivity of 0.73 g xylitol (g cells h)−1 was determined for C. guilliermondii ATCC 20216 after 120 h of growth at 30°C on a pH 5.0-buffered hydrolysate-containing medium. Xylitol production and yield by the three Candida strains was higher on prairie cordgrass than what was previously observed for the same strains after 120 h at 30° C when another North American prairie grass big bluestem served as the plant biomass hydrolysate indicating that prairie cordgrass may be a superior plant biomass substrate.

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Nitrogen addition affects plant biomass allocation but not allometric relationships among different organs across the globe

Journal of Plant Ecology ◽

10.1093/jpe/rtaa100 ◽

2020 ◽

Author(s):

Kai Yue ◽

Dario A Fornara ◽

Wang Li ◽

Xiangyin Ni ◽

Yan Peng ◽

...

Keyword(s):

Biomass Allocation ◽

Mass Fraction ◽

Plant Biomass ◽

Terrestrial Ecosystems ◽

Interactive Effects ◽

N Addition ◽

Allometric Relationships ◽

Optimal Partitioning ◽

Whole Plant ◽

Allocation Patterns

Abstract Aims Biomass allocation to different organs is a fundamental plant ecophysiological process to better respond to changing environments; yet, it remains poorly understood how patterns of biomass allocation respond to nitrogen (N) additions across terrestrial ecosystems worldwide. Methods We conducted a meta-analysis using 5474 pairwise observations from 333 articles to assess how N addition affected plant biomass and biomass allocation among different organs. We also tested the “ratio-based optimal partitioning” vs. the “isometric allocation” hypotheses to explain potential N addition effects on biomass allocation. Important findings We found that (1) N addition significantly increased whole plant biomass and the biomass of different organs, but decreased root:shoot ratio (RS) and root mass fraction (RMF) while no effects of N addition on leaf mass fraction (LMF) and stem mass fraction (SMF) at the global scale; (2) the effects of N addition on ratio-based biomass allocation were mediated by individual or interactive effects of moderator variables such as experimental conditions, plant functional types, latitudes, and rates of N addition; and (3) N addition did not affect allometric relationships among different organs, suggesting that decreases in RS and RMF may result from isometric allocation patterns following increases in whole plant biomass. Despite alteration of ratio-based biomass allocation between root and shoot by N addition, the unaffected allometric scaling relationships among different organs (including root vs. shoot) suggest that plant biomass allocation patterns are more appropriately explained by the isometric allocation hypothesis rather than the optimal partitioning hypothesis. Our findings contribute to better understand N-induced effects on allometric relationships of terrestrial plants, and suggest that these ecophysiological responses should be incorporated into models that aim to predict how terrestrial ecosystems may respond to enhanced N deposition under future global change scenarios.

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