Impacts of salinity and simulated herbivory on survival and reproduction of the threatened Gulf of St. Lawrence Aster, Symphyotrichum laurentianum

Botany ◽  
2010 ◽  
Vol 88 (8) ◽  
pp. 737-744 ◽  
Author(s):  
Justin Ancheta ◽  
Stephen B. Heard ◽  
Jeremy W. Lyons
Keyword(s):  
Leaf Area ◽  
Soil Salinity ◽  
Seed Set ◽  
Natural Populations ◽  
Growth Chamber ◽  
Simulated Herbivory ◽  
Chamber Experiment ◽  
Survival And Reproduction ◽  
Halophytic Plants ◽  
Solidago Sempervirens

Halophytic plants may experience joint, and potentially interacting, effects of salinity and herbivory on their survival and reproduction. We investigated the impacts of salinity and (simulated) herbivory on fitness in the Gulf of St. Lawrence Aster ( Symphyotrichum laurentianum (Fernald) Nesom; Asteraceae). In natural populations, this species experiences varying soil salinity and spill-over herbivory from insects associated with neighbouring seaside goldenrod ( Solidago sempervirens  L.). We subjected S. laurentianum individuals to three levels of simulated herbivory (0%, 20%, and 40% leaf-area removal) and three levels of salinity (0, 10, and 20 g·L–1) in three runs of a growth-chamber experiment. The effects of salinity and herbivory were always additive. Salinity consistently and strongly reduced survivorship, by as much as 80% at 20 g·L–1 salt, but significantly affected the seed set of survivors in only one run. Herbivory reduced survival significantly in one run (by 42% at 40% leaf-area removal) and reduced seed set of survivors (by 36% at 40% leaf-area removal) in another. While both stresses can have important effects on S. laurentianum fitness, the effects of salinity were more consistently strong than were the effects of herbivory, for both survival and seed set.

ASSESSMENT OF AVAILABLE SOIL SULPHUR IN AN 35S GROWTH CHAMBER EXPERIMENT

1974 ◽  
Vol 54 (3) ◽  
pp. 309-315 ◽  
Author(s):  
J. R. BETTANY ◽  
J. W. B. STEWART ◽  
E. H. HALSTEAD
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Growth Chamber ◽  
Yield Response ◽  
Laboratory Studies ◽  
Organic S ◽  
Chamber Experiment ◽  
Extractable Soil

Growth chamber and laboratory studies of four selected soils differing in C:N:S ratios and the percentage of total S present as HI-reducible S in the soil organic matter showed that: (1) the yield response of alfalfa to applied S occurred when the 0.01 M CaCl2-extractable soil SO4—S was less than 3.3 μg/g, (2) mineralization of soil organic S was unaffected by the addition of 25 μg S/g to the soils, and (3) the amount of S mineralized was not directly related to the quantity of total S, HI-S or the percentage of total S present as Hi-reducible S. It was noted that the largest amount of S mineralized occurred from the soil with the lowest C:N:S ratios.

scholarly journals PHOSPHORUS NUTRITION OF SOYBEANS AS AFFECTED BY PLACEMENT OF FERTILIZER PHOSPHORUS

1983 ◽  
Vol 63 (2) ◽  
pp. 199-210 ◽  
Author(s):  
C. W. BULLEN ◽  
R. J. SOPER ◽  
L. D. BAILEY
Keyword(s):  
Glycine Max ◽  
Total Phosphorus ◽  
Dry Matter ◽  
Field Experiments ◽  
Seedling Emergence ◽  
Phosphorus Uptake ◽  
Growth Chamber ◽  
Grain Yields ◽  
Chamber Experiment ◽  
Glycine Max L

Growth chamber and field experiments were conducted on Southern Manitoba soils, low in available soil phosphorus, to investigate the effects of various placement methods and levels of phosphorus fertilizer on soybean (Glycine max (L.) Merrill ’Maple Presto’). It was found that soybean responded well to applied phosphorus on low-P soil in growth chamber studies. In the first growth chamber experiment, P was applied in solution to 100%, 50%, 25%, 12.5% and 1% of the total soil volume. Dry matter yields, total phosphorus uptake and utilization of fertilizer P increased at each level of applied P as the size of the phosphated band was decreased. The results were partly attributed to greater chemical availability of P in the smaller zones of P fertilizer reaction. In a second growth chamber experiment, soybeans responded differently to phosphorus banded in six different locations. Placement of the fertilizer 2.5 cm directly below the seed was more effective in increasing dry matter yield, total phosphorus uptake and fertilizer P utilization than placement 2.5 cm and 5 cm away at the same depth or placement 5 cm below the seed, whether the band was directly below, 2.5 cm away or 5 cm away. Soybean yield responses in the field were greatest with P banded 2.5 cm directly below the seed on low-P soils. Placement of P 2.5 cm below the seed resulted in grain yields that were 64% and 50% higher (at the two sites) than those obtained in control plots. Sidebanding P, 2.5 cm below and 2.5 cm away from the seed at the same level of application, improved grain yields of control plots by 40% and 39%. Seed placement and broadcast applications of P were not as effective in increasing grain yields. Broadcasting P in fall or in spring at rates of up to 52.38 kg P/ha did not result in significantly higher grain yields than those obtained in control plots. Placement of P in contact with the seed appeared to reduce seedling emergence, resulting in depressed yields when 52.38 kg P/ha were applied. Key words: Glycine max L. Merrill, ’Maple Presto’

On the function of flowers

1985 ◽  
Vol 224 (1235) ◽  
pp. 223-265 ◽  
Keyword(s):  
Seed Set ◽  
Large Fraction ◽  
Natural Populations ◽  
Sexually Dimorphic ◽  
Male Organ ◽  
Total Pollen ◽  
Comparative Survey ◽  
Male Flowers ◽  
Almost All ◽  
Single Insect

Most flowers are bisexual in function, but counting secondary allocation to attractive structures such as the corolla as equally male and female leads to the paradoxical conclusion that plants bearing perfect flowers invariably allocate much more to female than to male function. A method of calculating the gender of secondary floral allocation is described, and it is speculated that this allocation is predominantly male. Observations and experiments with natural populations of herbs, designed to test this hypothesis gave the following major results, (i) Insects visit larger flowers more frequently ( Fragaria ), and removal of floral biomass causes a reduction in the frequency of insect visits proportional to the fraction of biomass removed ( Impatiens ). (ii) Removal of attractive structures may cause a decline in the probability that a fruit will be formed but has no effect on the number of seeds set per fruit; thus, mutilation of essentially solitary flowers has no effect on seed-set per fruit ( Impatiens ), while removal of flowers from inflorescences in a species that forms several many-seeded fruits per inflorescence reduces fruit-set per inflorescence but has no effect on seed-set per fruit ( Asclepias ), and removal of sterile flowers from an inflorescence in which the fertile flowers yield one-seeded fruits is effective in reducing seed-set per inflorescence ( Viburnum ), (iii) Larger flowers may disperse a greater fraction of their pollen in unit time ( Impatiens ) and the removal of flowers from inflorescences causes a steep reduction in total pollen exported and a weak decline in the quantity of pollen exported per flower ( Asclepias ). These results are consistent with the hypothesis that a single insect visit (or a very few visits) suffices to fertilize almost all available ovules and is procured by a very small allocation to attractive structures, while much greater allocation is necessary to procure the numerous visits required to disperse a large fraction of the pollen. This inference is supported by a comparative survey of sexually dimorphic plants, in which male flowers are generally larger than female flowers, male inflorescences bear more flowers, and male plants bear more inflorescences. It is concluded that the flower is primarily a male organ, in the sense that the bulk of allocation to secondary floral structures is designed to procure the export of pollen rather than the fertilization of ovules. This conclusion may be sensitive to whether it is the flower or the inflorescence as a whole that represents the primary unit of attraction to insects. It was found that the performance of a given flower was substantially affected by other flowers in the same compact inflorescence ( Asclepias ), though not by other inflorescences on the same plant nor by those borne by nearby plants ( Fragaria, Impatiens ). A general quantitative theory of flower and inflorescence design is outlined, and used to organize the extensive experimental results for Asclepias .

scholarly journals Components of relative growth rate and nitrogen productivity of Brussels sprouts and leeks grown at two widely differing light intensities

1996 ◽  
Vol 44 (1) ◽  
pp. 21-29 ◽  
Author(s):  
A. Van Der Werf ◽  
C.T. Enserink ◽  
A.L. Smit ◽  
R. Booij
Keyword(s):  
Growth Rate ◽  
Leaf Area ◽  
Relative Growth Rate ◽  
Biomass Production ◽  
Field Experiments ◽  
Growth Chamber ◽  
Brussels Sprouts ◽  
Relative Growth ◽  
Unit Leaf ◽  
Growth Chamber Studies

Young vegetative Brussels sprout and leek plants were grown in a growth chamber at a light intensity of 550 micro mol m-2 s-1 or at only 20% of that intensity. In both light treatments, Brussels sprouts had a relative growth rate (RGR) ~90% higher than that of leeks, which was mainly explained by a higher leaf area ratio (LAR; msuperscript 2/kg plant). Only minor differences in the physiological component (net assimilation rate) were observed between the 2 species within a light treatment. The higher LAR of Brussels sprouts was mainly explained by higher specific leaf area. Brussels sprouts had a higher rate of biomass production per unit internal N (N productivity) than leeks. This was mainly explained by a higher allocation of N to leaves and a higher rate of biomass production per unit leaf N. It is suggested that the higher biomass production per unit of N taken up in Brussels sprouts than leeks as observed in the field is explained by higher N productivity. The results obtained from the growth chamber studies are discussed in relation to field experiments and data from the literature.

THE EFFECT OF SULPHUR ON MANGANESE AND COPPER NUTRITION OF CANOLA

1989 ◽  
Vol 69 (1) ◽  
pp. 119-125 ◽  
Author(s):  
R. E. KARAMANOS ◽  
N. HODGE ◽  
J. W. B. STEWART
Keyword(s):  
Brassica Napus ◽  
Key Words ◽  
Organic Soil ◽  
Application Rate ◽  
Antagonistic Effect ◽  
Growth Chamber ◽  
Brassica Napus L ◽  
Chamber Experiment ◽  
Cu Deficiency ◽  
Cu Nutrition

A growth chamber experiment was conducted to assess the Mn and Cu nutrition of canola (Brassica napus L. 'Westar') and whether S nutrition has an impact on the Mn and Cu nutrition of this crop. Three rates of Mn (0, 25, and 50 mg kg−1), three of Cu (0, 5, and 10 mg kg−1) and three rates of S (10, 20, and 30 mg kg−1) were applied in all combinations to canola grown on an organic soil. High Mn:Cu ratios (> 15) led to Cu deficiency, which, at 10 and 20 mg S kg−1, was alleviated by Cu additions. The Mn-induced Cu deficiency was self-corrected at the 30 mg S kg−1 application rate. This was attributed to the alleviation of a Cu × Mo antagonistic effect through addition of S. Key words: Canola, available soil Mn and Cu, Mn × Cu × S interaction, S × Mo interaction, Cu × Mo interaction

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