Shoot apical growth and cataphyll initiation rates in provenances of Pinusconforta in Scotland

1976 ◽  
Vol 6 (4) ◽  
pp. 539-556 ◽  
Author(s):  
Melvin G. R. Cannell
Keyword(s):  
Late Summer ◽  
Growing Season ◽  
Height Growth ◽  
Early Summer ◽  
Model Matching ◽  
Matching Method ◽  
Apical Dome ◽  
Terminal Bud ◽  
Component C ◽  
Doubling Times

The dynamics of terminal bud development on seven 3-year-old nursery-grown provenances of Pinuscontorta Dougl. were monitored by sampling buds at 1- to 3-weekly intervals during one growing season. Differences in rates of cataphyll initiation occurred which were analysed in terms of (a) the projected areas of the apical domes, which changed over the season, (b) the relative rates at which the apical domes expanded radially during a plastochrone (square millimetres per square millimetre), as shown by the extent to which the new cataphyll primordia receded away from the domes, and (c) the projected areas of the tissues used to form new cataphyll primordia. Component a was a measure of the size of the apical dome meristems and b was a measure of their rates of 'activity.' A model-matching method is described to measure b.Those provenances which produced most cataphylls during the growing season developed and maintained large apical domes (component a above). There were unexpectedly small provenance differences in the apical dome 'activity' in midsummer (component b defined above), although differences occurred in spring and autumn. Differences in the projected areas of the new cataphyll primordia (component c) were inversely related to cataphyll initiation rates. Apical dome tissue doubling times in midsummer were estimated to be less than 120 h, irrespective of provenance.Inland provenances had small but relatively 'active' apical domes in spring, but they produced cataphyll primordia as products of this growth rather than reinvesting in apical dome 'capital.' Consequently, their apical domes remained small. Coastal Alaskan provenances, on the other hand, developed large apical domes, but these domes ceased to be very 'active' after the end of August. The apical domes on south coastal provenances did not become 'active' until early summer, but their domes were relatively large even in spring, became much larger by late summer, and they remained 'active' until mid-September.Implications are noted regarding cross-breeding of complementary genotypes to increase needle production and height growth.

The effects of summer shoot production on height growth components of seedlings of California red and white fir

1992 ◽  
Vol 22 (5) ◽  
pp. 690-698 ◽  
Author(s):  
Stephen W. Hallgren ◽  
John A. Helms
Keyword(s):  
Soil Moisture ◽  
Growing Season ◽  
Shoot Elongation ◽  
Height Growth ◽  
Shoot Morphology ◽  
Apical Dome ◽  
White Fir ◽  
Shoot Production ◽  
Terminal Shoot ◽  
Needle Primordia

Morphogenesis of the terminal shoot was studied in 2-year-old seedlings of California red fir (Abiesmagnifica A. Murr.) and two elevational sources of white fir (Abiesconcolor (Gord. & Glend.) Lindl.). Seedlings were either watered or left unwatered during the growing season in order to produce different shoot morphologies and seedlings with and without a summer shoot. Under favorable soil moisture, the frequency of summer shoot production was 32, 53, and 82% for red fir and high- and low-elevation white fir, respectively. Drought from mid-May to mid-September reduced summer shoot production to less than 1% in both species. Spring shoot morphology was not an indicator of capacity to produce a summer shoot. Rate of primordium production was directly related to apical dome diameter. However, when the normal spring increase in apical dome diameter was arrested by summer shoot elongation, the rate of primordium production appeared to be unaffected. Although the apical and subapical meristems were active at the same time, they did not appear to be antagonistic. The major effects of producing a summer shoot were as follows: (i) elongation of 60–120% more intemodes in the current growing season, (ii) production of 15–40% more needle primordia in the overwintering bud, (iii) production of 30–60% more primordia annually, and (iv) increase in the percentage of total primordium production that developed into needles from 60% to 75–80%.

scholarly journals Fungicide timing for control of summer rots of apples

2007 ◽  
Vol 60 ◽  
pp. 15-20
Author(s):  
K.R. Everett ◽  
O.E. Timudo-Torrevilla ◽  
J.T. Taylor ◽  
J. Yu
Keyword(s):  
Biological Control ◽  
Bacillus Subtilis ◽  
Serratia Marcescens ◽  
Late Summer ◽  
Growing Season ◽  
Early Summer ◽  
The Other ◽  
Effective Control ◽  
Lesion Diameter ◽  
Final Assessment

Control of preharvest summer rot in cv Royal Gala apple in the Waikato district during the 2006/2007 growing season was evaluated There were six treatments and an unsprayed control Three treatments investigated the effect of timing by applying tolyfluanid mancozeb captan and copper sequentially at 1014 day intervals in October and early November (spring) November and December (early summer) or January and February (late summer) The fourth treatment was two applications of carbendazim in early October (flowering) and there were two biological control treatments Bacillus subtilis QST713 and Serratia marcescens HR42 applied at 1014 day intervals from flowering (October) to harvest (February) Compared with the unsprayed treatment the most effective control was achieved by fungicide applications during either November/December or January/February Due to large variation in the data differences were not statistically significant but mean lesion diameter at final assessment for these treatments was 29 and 35 of controls respectively The other treatments did not control rots

Growth losses from winter drying (red belt damage) in lodgepole pine stands on the east slopes of the Rockies in Alberta

1987 ◽  
Vol 17 (10) ◽  
pp. 1289-1292 ◽  
Author(s):  
I. E. Bella ◽  
S. Navratil
Keyword(s):  
Lodgepole Pine ◽  
Growing Season ◽  
Height Growth ◽  
Yield Losses ◽  
Potential Yield ◽  
Terminal Bud ◽  
Growth Loss ◽  
Annual Volume ◽  
Pine Stands ◽  
Rotation Age

Red belt damage (reddening and death of foliage) occurs frequently in lodgepole pine Pinuscontorta var. latifolia Engelm. stands between certain elevations and may affect tree growth and even cause mortality. We examined growth impact in four pine stands (10, 55, 90, and 115 years old) where nearly all trees showed symptoms of damage. On young trees, visible damage ranged from 0 to 80% of foliage, and averaged about 35%. A highly significant reduction in height growth and terminal bud length (p < 0.01) of young trees was proportional to the amount of damage. As much as two-thirds growth loss occurred in trees with 60% or more necrotized foliage. On intermediate and mature lodgepole pine, reduction of annual volume increment in the growing season following damage was variable and reached as high as 50%, with no further significant reduction occurring in subsequent years. Potential yield losses at rotation age and forest management prescriptions for susceptible stands are presented.

scholarly journals Seasonal development of iron limitation in the sub-Antarctic zone

2018 ◽  
Vol 15 (14) ◽  
pp. 4647-4660 ◽  
Author(s):  
Thomas J. Ryan-Keogh ◽  
Sandy J. Thomalla ◽  
Thato N. Mtshali ◽  
Natasha R. van Horsten ◽  
Hazel J. Little
Keyword(s):  
Phytoplankton Community ◽  
Late Summer ◽  
Growing Season ◽  
Early Summer ◽  
Seasonal Development ◽  
Iron Availability ◽  
Iron Supply ◽  
Incubation Experiments ◽  
The Mean ◽  
Iron Addition

Abstract. The seasonal and sub-seasonal dynamics of iron availability within the sub-Antarctic zone (SAZ; ∼40–45∘ S) play an important role in the distribution, biomass and productivity of the phytoplankton community. The variability in iron availability is due to an interplay between winter entrainment, diapycnal diffusion, storm-driven entrainment, atmospheric deposition, iron scavenging and iron recycling processes. Biological observations utilizing grow-out iron addition incubation experiments were performed at different stages of the seasonal cycle within the SAZ to determine whether iron availability at the time of sampling was sufficient to meet biological demands at different times of the growing season. Here we demonstrate that at the beginning of the growing season, there is sufficient iron to meet the demands of the phytoplankton community, but that as the growing season develops the mean iron concentrations in the mixed layer decrease and are insufficient to meet biological demand. Phytoplankton increase their photosynthetic efficiency and net growth rates following iron addition from midsummer to late summer, with no differences determined during early summer, suggestive of seasonal iron depletion and an insufficient resupply of iron to meet biological demand. The result of this is residual macronutrients at the end of the growing season and the prevalence of the high-nutrient low-chlorophyll (HNLC) condition. We conclude that despite the prolonged growing season characteristic of the SAZ, which can extend into late summer/early autumn, results nonetheless suggest that iron supply mechanisms are insufficient to maintain potential maximal growth and productivity throughout the season.

scholarly journals Seasonal development of iron limitation in the sub-Antarctic zone

2018 ◽  
Author(s):  
Thomas J. Ryan-Keogh ◽  
Sandy J. Thomalla ◽  
Thato N. Mtshali ◽  
Natasha R. van Horsten ◽  
Hazel Little
Keyword(s):  
Phytoplankton Community ◽  
Late Summer ◽  
Growing Season ◽  
Early Summer ◽  
Seasonal Development ◽  
Iron Availability ◽  
Iron Supply ◽  
Incubation Experiments ◽  
High Nutrient ◽  
Iron Addition

Abstract. The seasonal and sub-seasonal dynamics of iron availability within the sub-Antarctic zone (SAZ, ~ 40–45° S) play an important role in the distribution, biomass and productivity of the phytoplankton community. The variability in iron availability is due to an interplay between winter entrainment, diapycnal diffusion, storm-driven entrainment, iron scavenging and iron recycling processes. Biological observations utilising grow-out iron addition incubation experiments were performed at different stages of the seasonal cycle within the SAZ to determine the importance of these supply mechanisms. Here we demonstrate that at the beginning of the growing season there is sufficient iron to meet the demands of the phytoplankton community, but as the growing season develops the supply mechanisms fail to meet this demand. Phytoplankton increase their photosynthetic efficiency and net growth rates following iron addition from mid to late summer, with no differences determined during early summer; suggestive of seasonal iron depletion and low iron resupply. The result of which is residual macronutrients at the end of the growing season, and the prevalence of the high-nutrient low-chlorophyll (HNLC) condition. We conclude that despite the prolonged growing season characteristic of the sub-Antarctic zone, which can extend into late summer/early autumn, the results suggest that the iron supply mechanisms are insufficient to maintain potential maximal growth and productivity throughout the season.

Timing of Fertilizer Application Important for Management of Southern Pine Seed Orchards

1983 ◽  
Vol 7 (2) ◽  
pp. 76-81
Author(s):  
R. C. Schmidtling
Keyword(s):  
Pinus Taeda ◽  
Late Summer ◽  
Growing Season ◽  
Pinus Elliottii ◽  
Fertilizer Application ◽  
Early Summer ◽  
Pinus Echinata ◽  
Optimum Time ◽  
Female Flowering ◽  
Pinus Taeda L

Abstract Fertilizers were applied at different dates during the growing season to orchard ramets of loblolly (Pinus taeda L), slash (Pinus elliottii Engelm. var. elliottii), shortleaf (Pinus echinata Mill.), and Virginia pines (Pinus virginiana Mill.) to determine optimum time to enhance flowering. Depending on species, female flowering was increased by applications in mid- to late summer. Male flowering was increased most by applications in early summer.

The effect of grazing on a perennial veldt grass, subterranean clover pasture

1952 ◽  
Vol 3 (2) ◽  
pp. 148 ◽  
Author(s):  
RC Rossiter
Keyword(s):  
Perennial Grass ◽  
Subterranean Clover ◽  
Late Summer ◽  
Growing Season ◽  
Early Summer ◽  
Pasture Production ◽  
Continuous Grazing ◽  
Winter Grazing ◽  
Consistent Treatment ◽  
Clover Pasture

The results of a grazing trial with Merino wether sheep on perennial veldt grass with subterranean clover are presented. During the four years 1944-45 to 1947-48 total pasture production under continuous grazing was almost identical with that under rotational grazing (one week's grazing followed by five weeks' rest). No consistent treatment differences were observed in sheep body-weight trends. In each year the weights increased during the growing season, remained stationary during early summer, and declined in late summer. The contribution of the perennial grass (Ehrharta calycina Sm.) declined rapidly with time, though more so under continuous grazing. This was associated with an increase in the proportion of subterranean clover in the sward. The lack of persistence of Ehrharta calycina is attributed to selective grazing, together with susceptibility to drastic defoliation. Alternative schemes for the use of this grass, involving restricted winter grazing, are suggested.

Control of height growth components in seedlings of California red and white fir by seed source and water stress

1988 ◽  
Vol 18 (5) ◽  
pp. 521-529 ◽  
Author(s):  
Stephen W. Hallgren ◽  
John A. Helms
Keyword(s):  
Growing Season ◽  
High Elevation ◽  
Height Growth ◽  
Current Season ◽  
Seed Sources ◽  
White Fir ◽  
Terminal Bud ◽  
Bud Growth ◽  
Induced Changes ◽  
Needle Primordia

Terminal bud growth in 2nd-year seedlings and subsequent elongation of the overwintering bud in the 3rd year were studied in California red fir (Abiesmagnifica A. Murr.) and two elevational sources of white fir (A. concolor (Gord. and Glend.) Lindl.). During each growing season the seedlings were either watered or left unwatered to provide 2nd and 3rd year treatments of wet–wet, dry–wet, wet–dry, and dry–dry seasons. Harvests were done biweekly during the second growing season and once at the end of the third growing season. Rate and duration of primordium production were negatively related and there were no differences among seed sources for the number of primordia produced in the 2nd year. Watering more than doubled the number of primordia, mainly through increasing the rate of production. Internode number and length were negatively related on a genetic and environmental basis. Changes in internode length tended to compensate for environmentally induced changes in internode number which resulted in a year to year stability in height growth. Height growth was more buffered against changes in internode number in red fir than in white fir. Watering induced a summer shoot in 80% of low-elevation white fir seedlings and 40% of red fir and high-elevation white fir seedlings. Summer shoots doubled the height increment for the current season and increased the number of needle primordia in the winter bud by 26%. The larger buds were the result of a prolonged period of primordium production.

Plant production after defoliation of native, Northern Mixed Prairie on hummocky terrain in Saskatchewan

2010 ◽  
Vol 90 (4) ◽  
pp. 421-433 ◽  
Author(s):  
A. Pantel ◽  
J T Romo ◽  
Y. Bai
Keyword(s):  
Standing Crop ◽  
Late Summer ◽  
Growing Season ◽  
Early Summer ◽  
Plant Production ◽  
Short Period ◽  
Dormant Season ◽  
Second Year ◽  
Mixed Prairie ◽  
June July

Resting plants after grazing is central to sustaining potential plant production. Growth of graminoids and forbs was determined for 3 yr after a single defoliation to 7.5 cm in May, June, July, August, September, October, November, or April on five different landform elements in the Northern Mixed Prairie. Green standing crop and cumulative green standing crop of forbs, graminoids, and their total varied with months of defoliation, landform elements, and years after defoliation. Green standing crop and cumulative green standing crop of forbs, graminoids, and their total was less than the control (P ≤ 0.05) on at least one of five landform elements until the second year after defoliation. This pattern of growth suggests the need to defer grazing for at least 1 yr after use to allow plants to regain their production potential. Plants defoliated early in the growing season recovered their production sooner or at the same time as those defoliated later in the growing season or when dormant. Generalizations that spring or early summer defoliation of native range reduces production and late summer or dormant season grazing has no effect on production warrants reconsideration where adequate rest is provided following a short period of grazing.Key words: Landform, landscape, primary production, rangeland, regrowth, standing crop

Effects of Dried Distillers’ Grains Cube Supplementation for Steers Grazing Introduced Pastures on Animal Performance and Forage Production

2021 ◽  
Vol 99 (Supplement_2) ◽  
pp. 12-13
Author(s):  
Jordan Adams ◽  
Rodney Farris ◽  
Scott Clawson ◽  
Earl Ward ◽  
Paul Beck
Keyword(s):  
Festuca Arundinacea ◽  
Statistical Power ◽  
Cynodon Dactylon ◽  
Animal Health ◽  
Late Summer ◽  
Early Summer ◽  
Distillers Grains ◽  
Forage Production ◽  
Trenbolone Acetate ◽  
Dried Distillers Grains

Abstract We evaluated the effects of supplementing dried distillers’ grains cubes (DDGS) and re-implantation of steers (n = 149; BW = 238 ± 13.8 kg) grazing tall fescue (Festuca arundinacea)/bermudagrass (Cynodon dactylon) pastures (n = 9 pastures, 7.2 ± 2.90 ha) from 14 April to 17 September 2020 (n = 155 d) in a split-plot design on steer performance and forage production. Main plot supplemental treatments (n = 3 pastures/treatment) included 1) Fertilized Control (FC), no supplementation on fertilized pastures (112 kg N/ha); 2) Fertilized Supplement (FS), supplemental DDGS fed at 2.9 kg 3-d/wk on fertilized pastures; and 3) Supplement (S), supplemented DDGS at 0.75% BW/d on unfertilized pastures prorated for 5-d/wk feeding. Steers were previously implanted during receiving with 40 mg trenbolone acetate and 8 mg estradiol (REV-G; Revalor G, Merck Animal Health). On July 7, steers in each pasture were randomly assigned to one of three re-implant treatments: 1) no re-implant; 2) REV-G; or 3) 200 mg progesterone and 20 mg estradiol (Synovex S, Zoetis Animal Health). Steers in FS and S gained more (P &lt; 0.01) than FC throughout the trial and final BW was greater (P &lt; 0.01) for FS and S compared with FC. Unexpectedly, re-implanting had no effect on ADG (P = 0.57) or BW (P = 0.34), but statistical power may be lacking. Supplemental efficiency was greater in the late summer for FS (P = 0.05) compared to S. Fertilizing pastures in FS and FC did not affect biomass (P = 0.39), however, CP was increased (P = 0.01) and acid and neutral detergent fibers tended to decrease (P = 0.06) relative to S in the early summer (April, May, June, and July), but did not differ in late summer (August and September). Based upon our analysis, DDGS is a suitable supplement and can replace N fertilizer for steers grazing introduced pastures.

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