scholarly journals Nitrogen Rate and Timing of Nitrogen Application in Poinsettia (Euphorbia pulcherrima Willd. Ex Klotz.)

HortScience ◽  
1994 ◽  
Vol 29 (11) ◽  
pp. 1309-1313 ◽  
Author(s):  
Mary Ann Rose ◽  
John W. White
Keyword(s):  
Leaf Area ◽  
Growth Stage ◽  
Floral Induction ◽  
Dry Weight ◽  
Plant Size ◽  
Growth Stages ◽  
N Availability ◽  
Regression Equations ◽  
Shoot Dry Weight ◽  
N Rates

`Celebrate 2' Poinsettias were grown for 8 weeks in a controlled-environment growth room until first signs of bract coloration. In growth stage I (GSI; weeks 1 through 4) low, medium, and high N rates (25, 75, and 125 mg N/liter, respectively) were applied by subirrigation (no leaching). Following floral induction [growth stage II (GSII), weeks 5 to 8], there were nine treatments: all possible combinations of the three N rates in GSI plus three rates (75, 125, and 175 mg N/liter) in GSII. Although >80% of shoot dry weight and >90% of total leaf area developed during growth GSII, reaching an acceptable plant size by week 8 depended on receiving adequate fertilization in growth GSI. In contrast, leaf chlorosis, noted in plants receiving the lowest rate in GSI, was rapidly reversed by increasing the N rate in GSII. Quadratic regression equations fitted to shoot dry weight and leaf area data predicted that using 125 mg N/liter in both growth stages gave maximum responses at week 8. However, using 75 mg N/liter in GSI and 125 mg N/liter in GSII also produced acceptable growth in poinsettias. Our results suggest that some growth restriction imposed by N availability during the first 4 weeks of growth may be acceptable and perhaps desirable to reduce growth regulator use and the environmental impact of overfertilization.

scholarly journals Drought, Paclobutrazol, Abscisic Acid, and Gibberellic Acid as Alternatives to Daminozide in Tomato Transplant Production

1992 ◽  
Vol 117 (2) ◽  
pp. 243-247 ◽  
Author(s):  
Joyce G. Latimer
Keyword(s):  
Abscisic Acid ◽  
Gibberellic Acid ◽  
Leaf Area ◽  
Fruit Size ◽  
Field Evaluation ◽  
Dry Weight ◽  
Plant Size ◽  
Stem Length ◽  
Stem Strength ◽  
Shoot Dry Weight

`Floradade' tomato (Lycopersicon esculentum Mill.) transplants treated with foliar sprays of paclobutrazol at 0, 14, 30, 60, or 90 ppm exhibited reductions in stem length, leaf area, and plant dry weight in a cubic response pattern. Gibberellic acid (GA) drenches, at 10, 100, or 250 ppm, increased stem length, leaf area, and plant dry weight. Daminozide (2500 or 5000 ppm) sprays reduced leaf area and dry weight, but 5000 ppm had no effect on stem length. Abscisic acid drenches, at 275, 660, or 1320 ppm, did not affect final plant size. In subsequent experiments to produce transplants for field evaluation, plants treated with paclobutrazol sprays at 90 (1987) and 14 or 60 ppm (1988) had smaller leaf area, stem length, and shoot dry weight than untreated plants. In 1987,90 ppm paclobutrazol reduced stem shear strength, while 2500 ppm daminozide increased stem strength relative to controls. In 1988, 2500 ppm daminozide increased transplant growth while 660 ppm abscisic acid had no effect. Paclobutrazol (14 ppm) and drought improved field establishment of transplants as measured by shoot dry weight gain after field planting. In 1988, total fruit yield was reduced by 60 ppm paclobutrazol and GA. Although fruit size was unaffected by treatments, fruit number was reduced by GA. Chemical names used: butanedioic acid mono (2,2-dimethylhydrazide) (daminozide); B-[(4-chlorophenyl)methyl]-α -(1,1-dimethylethyl) -N-1,2,4-triazole-1-ethanol (paclobutrazol).

scholarly journals Growth, Fruit Yield, and Ion Concentration in Tomato Genotypes after Pre- and Post-emergence Salt Treatments

1993 ◽  
Vol 118 (5) ◽  
pp. 655-660 ◽  
Author(s):  
M.C. Bolarín ◽  
F. Pérez-Alfocea ◽  
E.A. Cano ◽  
M.T. Estañ ◽  
M. Caro
Keyword(s):  
Salt Tolerance ◽  
Plant Growth ◽  
Growth Stage ◽  
Dry Weight ◽  
Fruit Yield ◽  
Ion Concentration ◽  
Growth Stages ◽  
Salt Tolerant ◽  
Shoot Dry Weight ◽  
Advanced Stages

The effects of increasing salinity on dry weight and ion concentration of shoots at various growth stages and on fruit yield in four tomato (Lycopersicon esculentum Mill.) genotypes were assessed. The salt treatments (35, 70, and 140 mm NaCl) were applied pre-emergence (seed sowing) (pre-E) and post-emergence (four-leaf stage) (post-E) and maintained during plant growth. Genotype salt tolerance, measured as shoot dry weight in response to increases in salt concentration, varied depending on plant growth stage and salt application time. When salt was applied pre-E, salt tolerance increased with plant age, whereas when applied post-E, 45-day-old plants were the most salt tolerant. Mature plants were similarly salt tolerant independent of the growth stage at which the salt treatments began. However, fruit yield of all genotypes was higher when salt was applied pre-E than post-E. Shoot dry weight decreased as shoot Cl and Na ion concentrations increased. During early growth stages, pre-E salt-treated plants had the highest Cl-and Na+ concentrations and the lowest shoot dry weights. However, at the advanced stages, shoot Cl- and Na Concentrations were equal for both salt application times. These results show that the plants must adapt to salinity during a period that allows them to develop a mechanism to regulate internal Cl- and Na+ concentrations and, thus, grow under high salinity.

scholarly journals EFFECT OF MINERAL DEFICIENCY ON MORPHOLOGICAL AND PHYSIOLOGICAL PARAMETERS AND ON SHOOT AND ROOT MINERAL PARTITIONING IN THREE SUNFLOWER VARIETIES / EFECTO DE LA FALTA DE ELEMENTOS MINERALAS SOBRE LOS PARAMENTROS MORFOLOGICOS Y FISIOLOGICOS Y REPARTICION DE ELEMENTOS MINERALES DE LA PARTE SOBRE EL SUELO Y DE LA RAIZ EN TRES VARIEDADES / INFLUENCE DE LA CARENCE D’ÉLÉMENTS MINÉRAUX SUR LES PARAMÈTRES MORPHOLOGIQUES ET PHYSIOLOGIQUES ET SUR LA DISTRIBUTION DES ÉLÉMENTS MINÉRAUX ENTRE LA PARTIE AÉRIENNE ET LA RACINE POUR TROIS SORTES DE TOURNESOL

Helia ◽  
2001 ◽  
Vol 24 (35) ◽  
pp. 135-148
Author(s):  
Mohammed El Midaoui ◽  
Ahmed Talouizte ◽  
Benbella Mohamed ◽  
Serieys Hervé ◽  
Ait Houssa Abdelhadi ◽  
...  
Keyword(s):  
Leaf Area ◽  
Dry Matter ◽  
Growth Parameters ◽  
Dry Weight ◽  
Mineral Deficiency ◽  
P Deficiency ◽  
Plant Parts ◽  
Shoot Dry Weight ◽  
K Deficiency ◽  
Matter Effect

SUMMARYAn experiment has been carried out in order to study the behaviour under mineral deficiency of three sunflower genotypes, a population variety (Oro 9) and two hybrids (Mirasol and Albena). Sunflower seedlings were submitted to five treatments: N deficiency (N0), P deficiency (P0), K deficiency (K0), N and K deficiency (N0K0) and a control. Plants were harvested when they reached 3-4 true pairs of leaves. Growth parameters measured (height, total leaf area, root length, root and shoot dry mater) were all significantly reduced by mineral deficiency. Leaf area was most reduced by N0 (-61%) and P0 (-56%). Total dry matter was most affected by N0 (-63%) and by N0K0 (-66%). Genotype comparisons showed that Oro 9 had the highest shoot dry matter while Albena had the lowest root dry matter. Effect of mineral deficiency on content and partitioning of N, P, K, Ca and Na was significant and varied according to treatments and among plant parts. Shoot dry weight was significantly correlated with root N content (r2=0.81) and root K content (r2=-0.61) for N0 and K0.

Effect of nitrogen fertilizer on growth and yield of semi-dwarf and tall varieties of winter wheat

1978 ◽  
Vol 91 (1) ◽  
pp. 31-45 ◽  
Author(s):  
I. Pearman ◽  
S. M. Thomas ◽  
G. N. Thorne
Keyword(s):  
Winter Wheat ◽  
Grain Yield ◽  
Leaf Area ◽  
Dry Weight ◽  
The Other ◽  
Growth And Yield ◽  
Shoot Dry Weight ◽  
Phosphorus And Potassium ◽  
Main Effects ◽  
Dwarf Variety

SummaryEight amounts of nitrogen ranging from 0 to 210 kg N/ha were applied to two tall and one semi-dwarf variety of winter wheat in the spring of 1975 and 1976. The tall varieties were Cappelle-Desprez and Maris Huntsman; the semi-dwarf variety was Maris Fundin in 1975 and Hobbit in 1976. Interactions between varieties and nitrogen were few and small compared with the main effects. All varieties produced their maximum grain yields with 180 kg N/ha. The yield of the semi-dwarf varieties, but not the others, decreased slightly with more nitrogen.Cappelle-Desprez yielded less grain than the other varieties in both years. In 1975 the yields of Maris Fundin and Maris Huntsman were similar and in 1976 Hobbit yielded more than Maris Huntsman. The varieties had similar numbers of ears at maturity and similar patterns of tillering. The semi-dwarf varieties had most grains per spikelet, and hence grains per ear, and Cappelle-Desprez had least. The semi-dwarf varieties had the smallest grains. The semi-dwarf varieties had less straw than the other varieties and hence the largest ratios of grain to total above-ground dry weight. The decrease in dry weight of stem and leaves between anthesis and maturity was similar for all varieties. In 1975 the efficiency of the top two leaves plus top internode in producing grain was the same for all varieties, but in 1976 Hobbit was more efficient than the other two. There were some small differences between varieties in nutrient uptake that were not related to differences in growth. Maris Fundin tended to have a greater phosphorus and potassium content than the tall varieties. Hobbit contained slightly less nitrogen than the tall varieties at maturity, and had a smaller concentration of nitrogen in the grain.Applying 210 kg N/ha doubled grain yield in 1975. Applying nitrogen resulted in a largeincrease in number of ears and a small increase in number of grains per ear due to the development of more fertile spikelets per ear. Nitrogen decreased dry weight per grain, especially of the semi-dwarf varieties. With extra nitrogen, straw dry weight at maturity, shoot dry weight atanthesis and leaf area were all increased relatively more than grain yield, and stems lost moredry weight between anthesis and maturity than without nitrogen. The year 1976 was exceptionallydry and nitrogen had only small effects in that it affected neither straw dry weight nor numberof ears but slightly increased grain yield by increasing the number of spikelets and number of grains per spikelet. It also increased leaf area proportionately to grain yield. In 1975 nitrogen increased evaporation of water from the crop before anthesis but decreased it after anthesis, even though it continued to increase the extraction of water from below 90 cm.

scholarly journals Exogenous Antioxidants Enhance Seedling Growth and Yield of Artificially Aged Cabbage and Lettuce Seeds

Horticulturae ◽  
2021 ◽  
Vol 7 (9) ◽  
pp. 274
Author(s):  
Ademola Adetunji ◽  
Sershen ◽  
Boby Varghese ◽  
Norman Pammenter
Keyword(s):  
Leaf Area ◽  
Seedling Growth ◽  
Seedling Emergence ◽  
Dry Weight ◽  
Growth And Yield ◽  
Seed Vigour ◽  
Beneficial Effects ◽  
Shoot Dry Weight ◽  
Antioxidant Defence System ◽  
Aged Seeds

Aged seeds exhibit compromised vigour in terms of germination, seedling emergence and growth, but this can to some extent be alleviated by invigoration treatments before sowing. This study aimed to investigate ageing rates and patterns in cabbage (Brassica oleraceae) and lettuce (Lactuca sativa) seeds and whether the beneficial effects of invigorating aged seeds with exogenous antioxidants translate to enhanced seedling performance. Seeds were artificially aged to 25% viability before soaking in 0.4 mM glycerol, 0.6 mM GSH and 0.2 mM trolox for cabbage, and 0.6 mM glycerol, GSH and trolox for lettuce; deionised water served as a control. After 14 days of sowing, seedling emergence percentage, mean emergence time, mean daily emergence, and time taken to 25% emergence were computed. Seedling vigour index, root and shoot dry weight, root:shoot ratio, leaf area, leaf area ratio, and leaf chlorophyll content were assessed 6 weeks after sowing. Furthermore, the photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (E), and chlorophyll fluorescence were measured 6 weeks after sowing. Notably, ageing resulted in the loss of seed vigour and viability at higher rates in lettuce than cabbage. Seed pretreatment with glycerol promoted seedling growth in both species and shoot dry weight in lettuce, while glycerol and GSH enhanced Pn, Gs and E in lettuce. Trolox also enhanced Pn and E in lettuce. The beneficial effects of the antioxidant treatments are thought to be associated with the protection of photosystems from oxidative stress and/or stimulation of enzymes involved in photosynthesis, possibly through an enhanced antioxidant defence system during the early development stages when seedlings are particularly vulnerable to stress.

scholarly journals Whole-plant Response of Six Poinsettia Cultivars to Three Fertilizer and Two Irrigation Regimes

1996 ◽  
Vol 121 (1) ◽  
pp. 69-76 ◽  
Author(s):  
Ursula Schuch ◽  
Richard A. Redak ◽  
James Bethke
Keyword(s):  
Leaf Area ◽  
Chlorophyll Content ◽  
Dry Weight ◽  
Shoot Biomass ◽  
Vegetative Development ◽  
Chlorophyll Contents ◽  
Shoot Dry Weight ◽  
Irrigation Regimes ◽  
Whole Plant ◽  
Leaf N

Six cultivars of poinsettia (Euphorbia pulcherrima Wind.), `Angelika White', `Celebrate 2', `Freedom Red', `Lilo Red', `Red Sails', and `Supjibi Red' were grown for 9 weeks during vegetative development under three constant-feed fertilizer treatments, 80,160, or 240 mg N/liter and two irrigation regimes, well-watered (high irrigation) or water deficient (low irrigation). Plants fertilized with 80 or 240 mg N/liter were 10% to 18% shorter, while those fertilized with 160 mg N/liter were 25 % shorter with low versus high irrigation. Leaf area and leaf dry weight increased linearly in response to increasing fertilizer concentrations. Low irrigation reduced leaf area, leaf, stem, and shoot dry weight 3670 to 41%. Cultivars responded similarly to irrigation and fertilizer treatments in all components of shoot biomass production and no interactions between the main effects and cultivars occurred. Stomatal conductance and transpiration decreased with increasing fertilizer rates or sometimes with low irrigation. Highest chlorophyll contents occurred in leaves of `Lilo Red' and `Freedom Red'. Leaves of plants fertilized with 80 mg N/liter were deficient in leaf N and had 40 % to 49 % lower leaf chlorophyll content compared to plants fertilized with 160 or 240 mg N/liter. Irrigation had no effect on leaf N or chlorophyll content. At the end of the experiment leaves of `Supjibi Red' and `Angelika White' contained higher concentrations of soluble proteins than the other four cultivars.

The effect of barley yellow dwarf virus on early plant growth in ryegrass (Lolium spp.)

1989 ◽  
Vol 40 (2) ◽  
pp. 293 ◽  
Author(s):  
DR Eagling ◽  
RJ Sward ◽  
GM Halloran
Keyword(s):  
Leaf Area ◽  
Growth Rates ◽  
Barley Yellow Dwarf Virus ◽  
Dry Weight ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
Root Dry Weight ◽  
Shoot Dry Weight ◽  
Barley Yellow Dwarf ◽  
Yellow Dwarf Virus

Measurements were made on the effect of barley yellow dwarf virus (BYDV) infection on the early growth of four commercial cultivars of ryegrass (Lolium spp.) under two different temperatures (24�C and 16�C). At 24'C, BYDV infection was associated with reduced root dry weight (30-40%) in all cultivars; the effect of infection on shoot dry weight and leaf area was variable. At 16�C, the effect of BYDV infection was variable, being associated with increases in root dry weight, shoot dry weight, and leaf area in one cultivar (Grasslands Ariki) and decreases in another (Victorian). In two other cultivars, root dry weight, shoot dry weight and leaf area were not significantly affected (P>0.05) by infection with BYDV.At 24�C, the reductions in root dry weight associated with BYDV infection were not concomitant with reductions in the root relative growth rates. Up to at least 28 days after inoculation (46-50 days after germination) reductions in root dry weight were associated with both aphid-feeding damage and virus infection. Experiments with the cultivar Victorian, showed that shoot dry weight was not significantly affected (P>0.05) by feeding with viruliferous (BYDV) or non-viruliferous aphids (Rhopalosiphum padi L.). At 16�C, changes in root and shoot dry weight were associated with changes in the root and shoot relative growth rates.

scholarly journals Biological Control of the Weedy Plant (Rumex crispus) at the Seedling Growth Stage by the Green Dock Beetle (Gastrophysa viridula)

2019 ◽  
Vol 28 (1) ◽  
pp. 21-31
Author(s):  
Khalid S. Alshallash Khalid S. Alshallash
Keyword(s):  
Biological Control ◽  
Seedling Growth ◽  
Growth Stage ◽  
Biological Control Agent ◽  
Dry Weight ◽  
Control Agent ◽  
Growth Stages ◽  
Rumex Crispus ◽  
Shoot Number ◽  
The Impact

In four glasshouse experiments, the effectiveness of the adult green dock beetle Gastrophysa viridula (Coleoptera: Chrysomelidae), at the effective number of applied individuals, for use as a biological control agent of curled dock, Rumex crispus (Polygonaceae) were studied. The feeding of the beetle was investigated at four different numbers of beetle (0, 1, 2, 3) and at four seedling growth stages of the plant, defined by the average of leaf area per plant (1-1.22 , 2-4.45, 3-11.56, and 4-71.52 cm2/plant). Grazing by one, two or three dock beetles did not result in a significant reduction in dock dry weight or shoot numbers at the youngest growth stage. However, both at later seedling growth stages were significantly affected (P ? 0.0001), at any beetles number. The increase of beetle numbers caused nonsignificant increased effect, in some trials, confirming the impact of a single beetle. Three months after beetle grazing, dock seedlings of first, second and third growth stages were not able to regrow, however, some plants at the 4th growth stage, re-emerged. This suggested that the highest effect of beetle's feeding occurs on the early seedling stages. Statistical analysis showed a positive correlation (0.77) between dry weight and shoot number at all the four seedling growth stages, thus confirming the impact of the beetle on both the dry weight and shoot numbers. Combining beetle grazing with other control methods at older dock seedling stages could, therefore, provide better suppression

Clopyralid Dose Response for Two Black Medic (Medicago lupulina) Growth Stages

2016 ◽  
Vol 30 (3) ◽  
pp. 717-724 ◽  
Author(s):  
Shaun M. Sharpe ◽  
Nathan S. Boyd ◽  
Peter J. Dittmar
Keyword(s):  
Dose Response ◽  
Growth Stage ◽  
Plant Size ◽  
Stem Length ◽  
Effective Dosage ◽  
Growth Stages ◽  
Response Curves ◽  
Measured Range ◽  
Large Growth ◽  
Small Growth

Black medic is a troublesome weed in commercial strawberry fields in Florida. It emerges during crop establishment from the planting holes punched in plastic mulches that are installed on raised beds. Clopyralid is registered for posttransplant applications at 140 to 280 g ae ha−1but growers typically report suppression, not control. An outdoor potted experiment was designed to model the black medic dose-response curve and determine the effect of plant size at application on control. Two plant sizes were selected: designated small (0.5- to 1-cm stem length) and large (3- to 6-cm stem length). Dose-response curves were generated using a log-logistic four-parameter model. At 22 d after treatment (DAT), there was a significant interaction between clopyralid rate and black medic growth stage on both epinasty (P = 0.0022) and chlorosis (P = 0.0055). The effective dosage to induce 90% (ED90) epinasty were 249.5 and 398.3 g ha−1for the small and large growth stages, respectively. The ED90 for chlorosis was 748.2 for the small growth stage, whereas the estimated value for the large was outside the measured range. For necrosis there was no significant effect of growth stage, and the ED90 was 1,856.3 g ha−1. The aboveground dry biomass ED90 for the small growth stage was 197.3 g ha−1, and the estimated ED90 value for the large was not within the measured range. Results indicate that clopyralid adequately controls black medic when applied at maximum label rates when stems were 0.5 to 1 cm long but not when plants were larger. Poor efficacy typically observed in commercial fields is likely due to black medic plant size or lack of herbicide coverage via shielding by strawberry plants.

Dog mustard (Erucastrum gallicum) response to crop competition

Weed Science ◽  
1997 ◽  
Vol 45 (3) ◽  
pp. 397-403
Author(s):  
David A. Wall
Keyword(s):  
Interspecific Competition ◽  
Leaf Area ◽  
Seed Production ◽  
Growth And Development ◽  
Dry Weight ◽  
Field Studies ◽  
Limiting Factor ◽  
Shoot Dry Weight ◽  
Summer Fallow ◽  
Crop Competition

Greenhouse studies suggested that dog mustard was less competitive than wheat, but of similar competitiveness to flax. In field studies, dog mustard growth and development were markedly affected by crop competition. Competition from flax and wheat reduced dog mustard leaf area, shoot dry weight, plant height, and seed production compared with the weed grown on summer-fallow. Dog mustard was a prolific seed producer when grown in the absence of interspecific competition. On summer-fallow, dog mustard produced as many as 79,100 seeds plant−1when moisture was not a limiting factor. However, average seed production was 19,400 and 8000 seeds plant−1in 1994 and 1995, respectively.

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