scholarly journals 301 c and n fluxes in brussels sprouts (Brassica oleracea VAR. gemmifera) during bud growth

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 473d-473
Author(s):  
Remmie Booij ◽  
Bert Meurs

The harvest season for Brussels sprouts runs mainly from September to March. During this period the daylength is relatively short and the light intensity is low. Bud growth occurs, when photosynthesis is low. The question is, whether actual photosynthetic rate or rcdistrubution of earlier fixed photosynthates is the main source for bud growth. The aim of the present experiment was first to determine the gain of C and N and the distribution of these plant constituents within the plant, and second the role of the apical bud. Partitioning of dry matter over the plant parts and the allocation along the stem were determined. Contents of C, N, NO3 and soluble sugars in the dry matter were ascertained, and the total amounts of these components could be determined. From this analysis fluxes were calculated and the role of redistribution was investigated. Redistribution of soluble sugars and N from leaves before shedding contributed substantially to bud growth. The apical bud did not affect total dry matter production, but if removed, more dry matter became available for bud growth in the top region of the plant, resulting in a higher total bud yield.

1974 ◽  
Vol 83 (3) ◽  
pp. 479-487 ◽  
Author(s):  
N. M. Fisher ◽  
G. M. Milbourn

SummaryThree field experiments are described in which the effect of plant density and date of stopping (removal of the apical bud) on the development of yield in several Brussels sprout cultivars was studied. In a fourth experiment, the effect of a leaf removal treatment was designed to assess the possible remobilization of dry matter to the buds from senescing leaves.A total plant dry weight of 1·2 kg/m2 was achieved with a hybrid cultivar at commercial densities. Although the crop growth rate was low in midsummer, growth continued until mid-October. Bud dry weight yield was curvilinearly related to plant density with 2 plants/m2 giving the highest yields of 0·35 kg/m2 in stopped crops in November. Rapid bud growth did not begin until September but the increase in bud dry weight continued into December and January. Early stopping increased bud dry weight yield and the ratio of bud weight to total shoot weight. In November, bud dry weight accounted for 25–40% of the total shoot dry weight for most treatments.In the leaf removal experiment, estimated net photosynthetic rate of the crop was greater than the bud growth rate up to the end of the experiment and there was no significant effect of removing leaves just prior to natural senescence on bud dry weight.The production and partition of dry matter is discussed in comparison with other vegetative crops. It is found that the proportion of total dry weight partitioned to the useful parts in Brussels sprouts is comparatively low. Factors controlling the date at which rapid bud growth begins are discussed. It is concluded that the dry matter in the axillary buds is derived from photosynthesis occurring at the time of bud growth and that the remobilization of dry matter from other plant parts is not of great importance.


1991 ◽  
Vol 117 (2) ◽  
pp. 207-212 ◽  
Author(s):  
S. J. Wilcockson ◽  
A. E. Abuzeid

SUMMARYIn 1984 and 1985, the growth of axillary buds of Brussels sprouts plants was studied at Cockle Park, Northumberland, UK. Bud growth commenced in late September or early October and continued at all nodes until the final harvest in December. Total bud yield increased at a broadly constant rate until late November but at a decreasing rate thereafter. Plants produced c. 100 nodes with buds ≥ 5 mm diameter. The largest buds were c. 40 mm diameter and 25 g fresh weight. Bud size increased from the base of the stem upwards to between the 20th and 40th nodes and then decreased towards the apex. Nodes 20–40 (20% of the total) produced c. 40–45% of total bud yield. The size profile of leaves along the stem followed a similar pattern to the buds and the largest buds were in the axils of the largest leaves. There were close relationships between bud fresh weight and size, bud fresh weight and size, bud fresh weight and volume and log10 bud fresh weight and log10 bud size (r2 ≥ 0·995). The density of buds was c. 0·8 and bud fresh weight doubled for each 5 mm increase in bud diameter.Current photosynthesis of the leaf canopy was apparently the major source of assimilates for bud growth. A C14 tracing experiment suggested that growth of individual buds was mainly supported by their subtending leaves. There was no evidence of re-translocation of dry matter from dying leaves or the stems to buds or of substantial production of dry matter by the buds themselves. Rates of bud photosynthesis were only about 10% of the rate of leaves. The continued increase in bud fresh weight and size at the lowest nodes when leaves were senescing rapidly and after they had abscissed was probably mainly the result of water uptake rather than dry matter accumulation.


1989 ◽  
Vol 16 (3) ◽  
pp. 265 ◽  
Author(s):  
TL Setter ◽  
H Greenway ◽  
T Kupkanchanakul

Submergence of rice in water at low CO2 concentrations was studied in phytotron experiments using plants in the 3rd to 4th leaf stage. Cultivars known to differ in tolerance to complete submergence were adversely affected by the same mechanisms but to a different degree. Submergence for 4-12 days either reduced dry weight production of the whole plant by 6 to 10 fold or even resulted in a loss of dry weight. Nevertheless, the emerging leaf elongated, and both ethanol insoluble material and protein content increased with time. These increases were associated with translocation of dry matter and nitrogen from expanded to expanding leaves. Submergence also reduced concentrations of soluble sugars and starch in all plant parts by 4 to 12 fold. In contrast, concentrations of potassium and free amino acids in shoots were either the same or, in the case of the emerging leaf, higher than in plants which were not submerged. These results indicate (i) these solutes were not limiting growth and (ii) the tissues retained their semipermeability to these solutes during submergence. Insufficient capacity of root metabolism in submerged plants was indicated by low rates of respiration, which persisted in the presence of glucose, and by a low ability to consume ethanol. A model is presented on the adverse effects of submergence of rice which considers possible interactions between CO2, low O2 and high ethylene concentrations.


2005 ◽  
Vol 53 (3) ◽  
pp. 293-301 ◽  
Author(s):  
M. Ismail

aluminium treatment caused a significant decrease in root length and dry matter yield in the shoots and roots of carrot (Daucus carota L.) and radish (Raphanus sativus L.) plants. this reduction was concomitant with a decrease in the accumulation of soluble sugars and total amino acids, whereas a significant increase in the proline content of the shoots and roots was detected. Soluble protein remained more or less unchanged when Al was applied at low and moderate levels. However, at higher Al levels, the losses in soluble sugars were accompanied by increases in soluble protein in radish, whereas in carrot the opposite effect was observed.  The application of phosphorus fertilizer to al-treated plants counteracted the toxic effect of aluminium by increasing root elongation and dry matter production. This was associated with high contents of soluble sugars and soluble protein as well as ca, mg and p, especially at low and moderate levels of aluminium


Author(s):  
R.E. Fitzgerald

Recent increases in the value of gold have led to renewed interest in gold mining - particularly by the dredging of the river flats bordering West Coast rivers. In any future licensing of such dredging, the rehabilitation of the "destroyed" land will be a major consideration. Nitrogen is the main nutrient limiting the growth of radiata pine on the gold dredge tailings; this paper outlines initial results of an exploratory legume-fertilizer trial on levelled tailings in the Taramakau River valley. Twelve legume species were grown with and without superphosphate (+ MO, Mg and K). Tree lucerne (Cytisus proliferus) , Russell lupin (Lupinus polyphyllus) and yellow tree lupin (L. arboreus) grew well without the application of fertilizer but the pasture legumes had substantially increased dry matter production where P was added - in white clover (Trifolium repens) dry matter production was increased from 5.4 to 8.9 t/ha; and total N was 180 and 310 kg N/ha. Tree nutrition and growth were greatly improved by association with a vigorous legume species, In addition, the presence of legumes improved the appearance of the tailings and with a pasture species grazing potential was created


OENO One ◽  
2007 ◽  
Vol 41 (2) ◽  
pp. 85 ◽  
Author(s):  
Imene Toumi ◽  
Wissal M'Sehli ◽  
Soumaya Bourgou ◽  
Neila Jallouli ◽  
Asma Bensalem-Fnayou ◽  
...  

<p style="text-align: justify;"><strong>Aims</strong>: The responses of two Vitis vinifera cultivars (Cardinal and Superior Seedless) and two rootstocks (110R and SO4) to drought, the effect of grafting and the interactions of scion/rootstock were investigated.</p><p style="text-align: justify;"><strong>Methods and results</strong>: The vines were subjected to a progressive water stress in greenhouse controlled conditions. At the end of the water stress treatments, physiological analyses were carried out (stem water potential, dry matter production, soluble sugars, proline as well as ions Na+ and K+). Drought was expressed by the drop of the stem water potential in the stressed vines as compared to their controls. Furthermore, tolerance and sensitivity were linked to the accumulation of soluble sugars and proline as well as the equilibrium of K+ and Na+ in the leaves.</p><p style="text-align: justify;"><strong>Conclusion</strong>: When ungrafted, Cardinal was more tolerant to water stress than Superior Seedless. The grafted vines exhibited more vigour, moreover, the combination of Cardinal with SO4 and Superior Seedless with 110R revealed to be the advantageous associations under water stress.</p><p style="text-align: justify;"><strong>Significance and impact of study</strong>: This work has been carried out to investigate the differential responses of grapevine cultivars to drought stress and the impact of grafting under water shortage conditions.</p>


2004 ◽  
Vol 61 (2) ◽  
pp. 216-223 ◽  
Author(s):  
Cynthia Torres de Toledo Machado ◽  
Ângela Maria Cangiani Furlani

The activity of the enzyme phosphatase (P-ase) is a physiological characteristic related to plant efficiency in relation to P acquisition and utilization, and is genetically variable. As part of a study on maize genotype characterization in relation to phosphorus (P) uptake and utilization efficiency, two experiments were set up to measure phosphatase (P-ase) activity in intact roots of six local and improved maize varieties and two sub-populations. Plants were grown at one P level in nutrient solution (4 mg L-1) and the P-ase activity assay was run using 17-day-old plants for varieties and 24-day-old plants for subpopulations. Shoot and root dry matter yields and P concentrations and contents in plant parts were determined, as well as P-efficiency indexes. Root P-ase activity differed among varieties, and highest enzimatic activities were observed in two local varieties -'Catetão' and 'Caiano' -and three improved varieties -'Sol da Manhã', 'Nitrodente' and 'BR 106'. 'Carioca', a local variety, had the lowest activity. Between subpopulations, 'ND2', with low yielding and poorly P-efficient plants, presented higher root P-ase activity as compared to 'ND10', high yielding and highly P-efficient plants. In general, subpopulations presented lower P-ase activities as compared to varieties. Positive and/or negative correlations were obtained between P-ase activity and P-efficiency characteristics, specific for the genotypes, not allowing inference on a general and clear association between root-secreted phosphatase and dry matter production or P acquisition. Genotypic variability must be known and considered before using P-ase activity as an indicator of P nutritional status, or P tolerance, adaptation and efficiency under low P conditions.


1997 ◽  
Vol 37 (1) ◽  
pp. 83 ◽  
Author(s):  
P. J. Hocking ◽  
P. J. Randall ◽  
D. De Marco ◽  
I. Bamforth

Summary. Field trials were conducted over 2 seasons at Greenethorpe and Canowindra in the Cowra region of New South Wales to develop and calibrate plant tests for assessing the nitrogen (N) status of canola (Brassica napus). Plants were tested at 3 and 7 growth stages up to the start of flowering at Greenethorpe and Canowindra, respectively. The petiole of the youngest mature leaf (YML) was the most suitable plant part to sample for tests based on nitrate-N. Suitable plant parts for tests based on total N were the YML petiole or lamina, or the whole shoot. There was good agreement between the 2 sites in the just-adequate fertiliser N rates (rates giving 90% of maximum yield) and the critical N concentrations in the plant parts tested. Critical nitrate-N concentrations in the fresh YML petiole for dry matter production at the time of sampling the plants decreased from 1.62 to 0.14 mg nitrate-N/g fresh weight between the 4–5 leaf rosette stage (4–5 RS) and the start of flowering (SF). Critical nitrate-N concentrations in the dry YML petiole decreased from 16.5 to 0.8 mg/g dry weight between 4–5 RS and SF. Critical total N concentrations decreased from 4.5 to 2.0, 7.2 to 5.0 and 6.2 to 2.8% dry weight, in the YML petiole, YML lamina, and whole shoot, respectively, between 4–5 RS and SF. Critical nitrate-N and total N concentrations for assessing potential seed yield were similar to those for dry matter production at the time of sampling for each of the growth stages. The critical total N concentrations obtained for the YML petiole and lamina, and the whole shoot before the start of stem elongation are likely to be less precise than the critical nitrate-N concentrations in the YML petiole because of the limited response of total N concentrations to increasing rates of fertiliser N. However, total N in the YML petiole or lamina, or in the whole shoot may be a better indicator of N status for plants sampled after the start of stem elongation as nitrate-N concentrations become low and more variable, and it is harder to identify the YML. The decline in critical N concentrations must be taken into account when interpreting the results of plant tests for diagnosing the N status of canola, as sampling needs to correspond to the plant growth stage for which a particular critical N concentration has been obtained.


HortScience ◽  
2001 ◽  
Vol 36 (7) ◽  
pp. 1219-1223 ◽  
Author(s):  
Gina E. Fernandez ◽  
Laura M. Butler ◽  
Frank J. Louws

The growth and development of three strawberry cultivars commonly grown in a plasticulture system were documented. Strawberry plants were harvested monthly and divided by roots, crown, leaves, flowers, and fruit and then dried in an oven. The dry matter production and resource allocation proceeded along a predictable pattern of development. The establishment phase was characterized by an active period of growth of root, crown and leaves in the fall. Through the winter, the plants underwent slow growth, ending in a transition period in the late winter/early spring when resources were allocated to both vegetative and reproductive growth. In the spring, all plant parts received significantly increased allocation of, or redistribution of, resources. Cultivars of California origin, `Chandler' and `Camarosa', displayed similar trends in yield, dry matter production, seasonal resource allocation, and growth analysis variables throughout the season. `Sweet Charlie', a cultivar from Florida, showed lower dry matter accumulation and relative growth rate in the spring, higher harvest index and lower yield than the California cultivars.


1962 ◽  
Vol 2 (7) ◽  
pp. 221 ◽  
Author(s):  
MJT Norman

At Katherine, N.T., between 1959-60 and 1961-62, the performance of Townsville lucerne alone and of mixtures of Townsville lucerne with Gayndah buffel grass, Biloela buffel grass, birdwood grass, and Sorghum almum was compared at three frequencies of wet-season cutting. The two most satisfactory mixtures, Townsville lucerne with Gaynahh buffel and birdwood grass, differed little in performance. Over three years, their average dry matter production exceeded that of Townsville lucerne alone by 45 per cent, but average nitrogen production was not appreciably greater than that of the pure legume pasture. Biloela buffel grass is considered to be an unsuitable companion grass for Townsville lucerne because of its competitive power. After three years, the dry matter contribution of the legume in Biloela buffel mixtures was only 18 per cent under the most favourable cutting treatment. The Sorghum almum mixture gave the highest dry matter yield in the first year, but the grass did not survive well, and by the third year the pasture was mainly Townsville lucerne. Sorghum almum may be useful in providing bulk in the early years of an intended pure legume pasture. The role of a perennial grass component in Townsville lucerne pastures is discussed.


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