A quantitative study of the effects of gibberellic acid on the growth of Festuca arundinacea

1968 ◽  
Vol 19 (2) ◽  
pp. 221 ◽  
Author(s):  
DG Morgan

Single plants of Festuca arundinacea (cv. S170) were treated with gibberellic acid (GA) and the sequence of effects on the growth of the whole plant and of various organs followed by means of growth analysis. The first effect of GA was to change the distribution of dry matter between shoot and root and between tillers within the shoot without affecting total plant weight. Shoot growth was increased and resulted in a larger amount of photosynthetic tissue with a higher net assimilation rate; total plant weight increased as a consequence of these effects. The significance of these results in interpreting previous work on the effects of GA on dry matter production in grasses and other plants is discussed.

Weed Science ◽  
1988 ◽  
Vol 36 (6) ◽  
pp. 751-757 ◽  
Author(s):  
David T. Patterson ◽  
Maxine T. Highsmith ◽  
Elizabeth P. Flint

Cotton, spurred anoda, and velvetleaf were grown in controlled-environment chambers at day/night temperatures of 32/23 or 26/17 C and CO2concentrations of 350 or 700 ppm. After 5 weeks, CO2enrichment to 700 ppm increased dry matter accumulation by 38, 26, and 29% in cotton, spurred anoda, and velvetleaf, respectively, at 26/17 C and by 61, 41, and 29% at 32/23 C. Increases in leaf weight accounted for over 80% of the increase in total plant weight in cotton and spurred anoda in both temperature regimes. Leaf area was not increased by CO2enrichment. The observed increases in dry matter production with CO2enrichment were caused by increased net assimilation rate. In a second experiment, plants were grown at 350 ppm CO2and 29/23 C day/night for 17 days before exposure to 700 ppm CO2at 26/17 C for 1 week. Short-term exposure to high CO2significantly increased net assimilation rate, dry matter production, total dry weight, leaf dry weight, and specific leaf weight in comparison with plants maintained at 350 ppm CO2at 26/17 C. Increases in leaf weight in response to short-term CO2enrichment accounted for 100, 87, and 68% of the observed increase in total plant dry weight of cotton, spurred anoda, and velvetleaf, respectively. Comparisons among the species showed that CO2enrichment decreased the weed/crop ratio for total dry weight, possibly indicating a potential competitive advantage for cotton under elevated CO2, even at suboptimum temperatures.


1981 ◽  
Vol 97 (2) ◽  
pp. 437-443 ◽  
Author(s):  
R. K. Pandey ◽  
V. B. Singh

SummaryField investigations were carried out to study the effect of partial defoliation on dry-matter production and seed yield of urd bean. Partial defoliation during the vegetative and/or reproductive phase reduced seed yield. The severity of yield reduction was dependent on the stage of crop development and the degree of defoliation. The reduction of total dry-matter production by defoliation was accompanied by a decrease in crop growth rate and leaf/plant weight ratio. The net assimilation rate was higher in defoliated plants from 40 to 60 days after sowing. The reduction in seed yield due to defoliation was highly due to a reduction in the number of pods per plant, and also sometimes in the number of seeds per pod and in 100-seed weight.


1980 ◽  
Vol 28 (4) ◽  
pp. 199-210
Author(s):  
F.T.J.M. Fortuin ◽  
S.W.P. Omta

The cultivation of S. nigrum was studied in West Java. Growth analysis showed that individual plant weight reached 1070 g 113 days after planting. When fruits and leaves were harvested the total yield was 580 g berries/plant (16.5 t/ha) and 28 g leaves/plant (0.8 t/ha). Picking the leaves influenced plant shape, relative growth rate and net assimilation rate. Shading caused a decline in total plant weight and changes in the distribution of biomass; the production of fruits was strongly affected, whereas the production of edible leaves was not affected by 35-60% shade and only moderately affected by 75-85% shade. Leaves from plants grown in shade were larger and thinner than those from plants in full light. There was no indication that the berries were toxic. (Abstract retrieved from CAB Abstracts by CABI’s permission)


1976 ◽  
Vol 12 (4) ◽  
pp. 385-394 ◽  
Author(s):  
D. O. Huett ◽  
G. H. O'Neill

SUMMARYThe growth and development of a short-season sweet potato (Nemagold) and a long-season cultivar (White Maltese) were compared quantitatively in sub-tropical Australia and also with growth data for Nemagold in a temperate environment. Total and storage root dry matter production (DMP) followed autocatalytic equations, with similar whole plant DMP from planting to week 25 for both cultivars but plateauing (at 90% of asymptotic weight) at week 23 for Nemagold (448 g) with favourable temperatures and at week 38 for White Maltese (813 g) when temperatures were unfavourable. Storage root DMP of Nemagold plateaued at week 23 (246 g) and at week 36 (219 g) for White Maltese. Data are given on other attributes and on phasic development.


Weed Science ◽  
1983 ◽  
Vol 31 (3) ◽  
pp. 318-323 ◽  
Author(s):  
David T. Patterson ◽  
Elizabeth P. Flint

Growth dynamics, water relations, and photosynthesis of soybean [Glycine max(L.) Merr. ‘Ransom’], common cocklebur (Xanthium pensylvanicumWallr.), jimsonweed (Datura stramoniumL.), prickly sida (Sida spinosaL.), sicklepod (Cassia obtusifoliaL.), smooth pigweed (Amaranthus hybridusL.), spurred anoda [Anoda cristata(L.) Schlect.], and velvetleaf (Abutilon theophrastiMedic.) were compared in a controlled-environment greenhouse programmed for 32C day and 23C night temperatures. Net photosynthetic rates, net assimilation rates, and water-use efficiency on a whole-plant or single-leaf basis were greatest in the C4-plant, smooth pigweed. Total dry-matter production at 29 days after planting was greatest in common cocklebur and least in jimsonweed. Interspecific differences in dry-matter production were highly positively correlated with leaf area duration and negatively correlated with net assimilation rate. Threshold leaf water-potential levels causing stomatal closure varied among species. The stomata of jimsonweed were the most sensitive to water stress and those of prickly sida were the least sensitive.


1968 ◽  
Vol 19 (6) ◽  
pp. 927 ◽  
Author(s):  
MA Foale

The growth of three coconut cultivars of the tall type from germination up to 17 months of age was compared by growth analysis. These cultivars differ considerably in mean nut size. Within each cultivar a comparison was also made between the growth of seedlings from small, medium, and large nuts. There were considerable differences between cultivars in seedling growth up to 2 months but these differences did not persist. Similarly differences due to nut size within cultivars were recorded at early harvests but had disappeared by 6 months. Thus neither genotype nor nut size had any sustained effect on the plant size. Consumption of endosperm depended on seed size: evidently a lower, compensating net assimilation rate occurred in plants with large nuts to give a similar total supply of assimilate. This suggests that the potential supply of assimilate was not limiting the growth rate. Large nuts transfer dry matter from the endosperm more rapidly than do smaller nuts; hence under unfavourable conditions for photosynthesis, larger nuts may produce larger seedlings. It is suggested that any seedling selection should be done in a favourable nursery environment so that emphasis is placed on differences in seedling vigour due to genetic variation.


1988 ◽  
Vol 15 (6) ◽  
pp. 815 ◽  
Author(s):  
GC Wright ◽  
KT Hubick ◽  
GD Farquhar

Variation in water-use efficiency (W, g of total dry matter produced/kg water used), and its correlation with cultivar isotope discrimination in leaves (Δ) was assessed in peanut plants grown in small canopies in the field. Plants were grown in separate minilysimeters that were both embedded in the ground and positioned above the crop. Differences among cultivars were found in W and � and the relationship between W and Δ was compared for plants grown in open and closed canopies. Genetic variability in W in plants grown in the field under non-limiting water conditions was demonstrated, with Tifton-8, of Virginia habit, having the highest W (3.71 g/kg) and Rangkasbitung, an Indonesian cultivar of Spanish habit, the lowest (2.46 g/ kg). Variability in W was due to variation in total dry matter production more than that of water use. A strong negative correlation was found between Δ and W, and also between Δ and total dry matter. The relationship between whole plant W, including roots, and Δ was stronger than that between shoot W, without roots and Δ. The improvement occurred because of variation among cultivars in the root to shoot ratio. This highlights the importance of taking account of root dry matter in studies concerning W. There were significant differences in W and Δ between plants in pots above-ground compared to pots in the ground, with above-ground plants having significantly lower values of both W and Δ. The ranking of W and Δ among cultivars was not affected by the contrast in environment, which suggests these parameters are under strong genetic control. Total above-ground dry matter yield at maturity was negatively correlated with Δ, while pod yield was not. It appears a negative association between harvest index and Δ may exist; however not all cultivars used in this and other studies follow this response. Both water-use efficiency, Wand total dry matter production are negatively correlated with Δ in leaves of peanut plants grown in small canopies in the field. Measurement of Δ may prove a useful trait for selecting cultivars with improved W and total dry matter yield under field conditions.


2011 ◽  
Vol 57 (No. 4) ◽  
pp. 160-165 ◽  
Author(s):  
F. Hrabě ◽  
P. Knot

In 2004&ndash;2009, a small-plot trial was conducted on permanent grassland dominated by Festuca arundinacea Schreb. on the mesohygrophytic site in order to evaluate effects of four levels of nutrition: F<sub>1</sub> = without NPK fertilization, F<sub>2 </sub>= P<sub>30</sub> + K<sub>60</sub>, F<sub>3</sub> = N90 + P<sub>30</sub> + K<sub>60</sub>, F<sub>4</sub> = N<sub>180</sub> + P<sub>30</sub> + K<sub>60</sub> kg/ha), four levels of cutting intensity (I<sub>1</sub>-4, I<sub>2</sub>-3, I<sub>3</sub>-2, early, I<sub>4</sub>-2, late cut) and their interactive influence, i.e. a total of 16 variants on the production of forage dry matter, production of crude protein (CD) and net energy of lactation (NEL) per hectare. The dominant influence of N-nutrition is documented by significant differences in forage dry matter (DM) production between the variants (with the exception of F<sub>1</sub>/F<sub>2</sub>) ranging from 4.41&ndash;4.80 to 8.44&ndash;9.83 t/ha. The effect of different exploitation level on the production is subdominant and no significant differences were found either in the production of forage DM<br />(I<sub>1</sub>-6.41 &ndash; I<sub>2</sub>-6.59 &ndash; I<sub>3</sub>-6.97 &ndash; I<sub>4</sub>-7.50 t/ha) or in the production of nutrients. Management models to be recommended for the given type of sward with respect to the interactive influence, efficacy of forage production and quality are as follows: (a) three cuts/180 kg N + PK/ha with forage suitable for dairy cows; (b) two cuts/90 kg N + PK/ha with forage suitable for cattle breeds kept for meat.


2017 ◽  
Vol 35 (3) ◽  
pp. 358-363 ◽  
Author(s):  
Adilson C Antônio ◽  
Derly JH Silva ◽  
Wagner L Araújo ◽  
Paulo R Cecon

ABSTRACT The objective of this work was to analyze the growth of the Upiã tomato cultivar in the Vertical, Crossed Fence and Viçosa cultivation systems, in order to obtain explanations for the productive gains achieved in the Viçosa system. The experiment was conducted in Viçosa, Minas Gerais State, Brazil, from August 21st to December 5th, 2012, in the scheme of subdivided plots, being the plots represented by the cultivation systems: Vertical, using tape, 1.0×0.5 m spacing; Crossed Fence, staked with bamboo, 1.0x0.5 m spacing; and Viçosa, using tape, 2.0x0.2 m spacing. The subplots were composed by the sampling times of the plants: 15, 30, 45, 60 and 75 days after transplanting. The experimental design was in randomized blocks, with four replications. Each plot was composed by three lines of 10 plants, making a total of 30 plants per plot, being evaluated the four central plants of each plot. We evaluated the dry matter of leaves (MSF), stem (MSC), inflorescences (MSI), fruits (MSFr) and total (MST). Using the foliar area index, measured by digital scanners and the previously obtained dry masses, we determined the physiological growth indices: foliar area index (IAF), specific foliar area (AFE), relative growth rate (TCR), and net assimilation rate (TAL). The Viçosa system altered the growth pattern of the tomato, quantified by the growth analysis, in comparison to Crossed and Vertical Fences. The prolongation of the second growth phase for the dry matter of fruits could possibly explain the productive gains obtained in the Viçosa system. Additional studies are required in order to clarify the relationship between the duration of the second phase of fruit dry matter growth, the physiological indexes AFE, IAF and TAL with the size and fruit yield of the tomato.


1967 ◽  
Vol 45 (11) ◽  
pp. 2063-2072 ◽  
Author(s):  
Holger Brix

Seedlings of Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) were grown in growth chambers under all combinations of three temperatures (13, 18, and 24 °C) and three light intensities (450, 1000, and 1800 ft-c). Dry matter production of leaves, stem, and roots was determined at 65 and 100 days after germination. The leaf area produced per unit of leaf dry weight and the dry matter distribution to the plant organs was measured. Net assimilation rates between the ages of 65 and 100 days were calculated. Rates of photosynthesis per unit of leaf were determined at different light intensities and temperatures, and rates of respiration of plant top and of roots were found for different temperatures.Increasing light intensity affected dry matter production in two opposing ways: (i) it increased the rate of photosynthesis per unit leaf area, and (ii) it decreased the leaf area added per unit of dry matter produced. A pronounced increase in growth with increase in temperature from 13 to 18 °C was a result of a temperature influence on production of leaf area rather than the effect of photosynthesis per unit of leaf. Net assimilation rates decreased with increase in temperature at all light intensities.


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