Growth response of two varieties of slash pine seedlings to chronic ozone exposures

1985 ◽  
Vol 63 (12) ◽  
pp. 2369-2376 ◽  
Author(s):  
W. E. Hogsett ◽  
M. Plocher ◽  
V. Wildman ◽  
D. T. Tingey ◽  
J. P. Bennett

Two geographical varieties of Pinus elliottii (Engelm.) seedlings, elliottii and densa, were exposed continuously to two daily peak exposure profiles of ozone having 7-h (0900–1600) seasonal means of 0.104 and 0.076 ppm and charcoal-filtered air over a 112-day period. The profiles represented a daily rise and decline of hourly ozone concentration. They were constructed with a daily hourly maximum, which for one profile (0.126 μL/L) exceeded the current ozone standard daily; the standard was not exceeded for the other profile (0.094 μL/L). Destructive harvests at 7-day intervals over the exposure period were employed to assess visible injury and to construct growth curves for stem diameter, plant height, top and root dry weight, and needle number and length. The visible injury was slight, yet all the growth parameters decreased significantly with time and ozone concentration; root growth was the most severely impacted. The observed growth response and visible injury of the two varieties were similar. Seed germination was not affected by ozone exposure.

1992 ◽  
Vol 22 (5) ◽  
pp. 756-760 ◽  
Author(s):  
Joanne Rebbeck ◽  
Keith F. Jensen ◽  
Michael S. Greenwood

Grafted juvenile and mature scions of red spruce (Picearubens Sarg.) were grown in open-top chambers at a low-elevation site in central Maine to determine if developmental age of tissue affects response to oxidant pollution. After 18 weeks of ozone exposure, grafted red spruce showed little or no growth response to ozone. No significant ozone effect on biomass production was measured, although there were significant differences between juvenile and mature scions. At the final harvest, juvenile scion stem, stem needles, branches, branch needles, and roots had 60, 18, 74, 73, and 35% more dry weight, respectively, than mature scions. Despite the observed differences in growth and biomass production, the two graft types did not differ in their responses to ozone, suggesting that tissue age may not be a factor in ozone-tolerant woody species such as red spruce. It does not preclude the importance of assessing the influence of age on other woody species' response to air pollution. This type of information is critical for extrapolation of seedling data to field conditions with mature trees.


2015 ◽  
Vol 45 (1–2) ◽  
pp. 143-158
Author(s):  
Teresa Gowin ◽  
Leokadiusz Ubysz

Scots pine seedlings were grown in pots from seed under outside conditions. Plant material was harvested ten times in fortnight periods, throughout the growing season. At each harvest, each plant was divided into particular organs and their dimensions as well as fresh and dry weight were determined. Seasonal course of growth of particular organs as well as changes in specific leaf area and distribution of dry matter between shoot and root were investigated. Net assimilation rate (NAR) and relative growth rate (RGR) were calculated from the fitted logistic growth curves.


HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1050A-1050
Author(s):  
Robert R. Tripepi ◽  
Mary W. George

Seedlings of several conifer species can be difficult to transplant, with the problem often related to poor root regeneration. The objective of this study was to determine if corkbark fir (Abies lasiocarpa arizonica) seedlings or pinyon pine (Pinus edulis) seedlings would produce more root growth when grown in a Missouri gravel bed growing system compared to field soil. The 3–0 fir seedlings and 4–0 pine seedlings were planted in a gravel bed in mid-April. The gravel bed was 3 m × 3.7 m and was filled with a mixture of 60% pea gravel (1 cm minus), 30% Turface®, and 10% silica sand (by volume). A field bed 3 m × 3.7 m in size was also prepared. Fir seedlings were harvested in September and October, but pinyon pine seedlings were harvested only in October due to their poor transplant survival. Plant heights, stem diameters, and root volumes, as well as root and shoot dry weights, were determined at harvest. Of all the measured growth parameters for both species, only root dry weights and root volumes were significantly different. In particular, fir seedlings grown in the gravel bed produced at least 30% more root dry weight and 74% more root volume than those planted in field soil whether plants were harvested in September or October. Likewise, pine seedlings grown in gravel produced at least 37% more root dry weight and 86% more root volume than those grown in soil. In addition, only 10.6% of the pine seedlings planted in soil survived transplanting, but 23.3% of those grown in the gravel bed survived. This study demonstrated that corkbark fir and pinyon pine seedlings grown in a gravel bed produced larger root systems than those planted into field soil, and the gravel bed also improved pinyon pine seedling survival after transplanting.


HortScience ◽  
2004 ◽  
Vol 39 (2) ◽  
pp. 280-286 ◽  
Author(s):  
Daphne L. Richards ◽  
David Wm. Reed

New Guinea impatiens (Impatiens hawkeri Bull.) `Illusion' were grown in a recirculating subirrigation system under various rates and placements of 14N-6.1P-11.6K (Osmocote; Scotts-Sierra, Marysville, Ohio) resin-coated, controlled-release fertilizer (CRF). Four CRF placements (incorporated, top-dressed, bottom, and dibble) were tested. Incorporated placement yielded slightly greater dry weights than the other placements. A rate experiment tested incorporating from 0.5 to 2 times the fertilizer manufacturer's recommended rate of 7.11 kg·m-3. All shoot growth parameters (height, leaf number, shoot, and root fresh and dry weight) exhibited a significant quadratic response, as exemplified by shoot dry weight, where shoot dry weight increased up to the 1.5× rate, after which shoot dry weight decreased. A quadratic response surface model revealed that the optimum rate response ranged from 1.16× rate for height to 1.47× rate for shoot dry weight. The lower bound of the 95% confidence interval (CI) would be the lowest rate at which one could expect maximum growth response. The lower bound of the 95% CI varied from 0.56× rate for height to 1.30× rate for shoot dry weight. Thus, the lowest rate that would be within the 95% CI for all growth parameters, and thus yield maximum growth response, would be the 1.30× rate. Electrical conductivity (EC) of the growing media increased significantly with increasing CRF rate. At all rates, EC was significantly greater in the top layer than in the middle and bottom layers. Only in the 1.75× and 2× rates did EC exceed the recommended EC levels in the middle and bottom layer. All rates >0.75× exceeded recommended EC in the top layer. Release characteristics and total nutrient balance of the CRF was compared in subirrigated and top-watered systems. There was no significant difference between top-watered and subirrigated treatments for the amount of K recovered in plant tops and released from prills. By day 84, in subirrigation, 46% of the K was still in the prills, 41% was recovered in the plant tops, and 22% was recovered in the medium. Similar results were obtained in the top-watering treatment, except that a lesser amount was recovered in the medium (9%) and a small amount (4%) was recovered in the leachate. The uptake of K by plants and release of K by the CRF were inversely proportional and linear with respect to time. Of the K released from the prills, 77% and 83% were recovered in the plant tops for subirrigation and top-watering, respectively, indicating very high fertilizer use efficiency.


1996 ◽  
Vol 26 (10) ◽  
pp. 1715-1723 ◽  
Author(s):  
R.A. Reinert ◽  
S.R. Shafer ◽  
G. Eason ◽  
S.J. Horton ◽  
M.M. Schoeneberger

Acidic rain and ozone (O3) may have serious consequences on the growth and development of loblolly pine (Pinustaeda L.), a tree species of major economic importance in the southeastern United States. In two independent studies, seedlings of open-pollinated families of loblolly pine were exposed to five concentrations of O3 (0, 80, 160, 240, or 320 nL•L−1) and three simulated rain acidities (pH 5.3, 4.3, or 3.3). Following 23 weeks of growth (12 weeks in charcoal-filtered air and 11 weeks of O3 and simulated acidic rain exposures), stem height, secondary needle dry weight, top and total seedling dry weight, and root/shoot dry weight ratio all were related negatively and linearly with O3 concentration. Stem diameter and root dry weight were also suppressed by O3. Suppression of the growth parameters ranged from 14 to 35% for the greatest O3 concentration. Acidity of simulated rain did not affect seedlings, nor did it affect seedling responses to O3. Results indicate that acid rain probably has little effect on growth of loblolly pine seedlings, but O3 can suppress growth to varying degrees depending on family.


2013 ◽  
Vol 74 (4) ◽  
pp. 307-314 ◽  
Author(s):  
Mariusz Kormanek ◽  
Jacek Banach ◽  
Michał Ryba

Abstract The paper presents research on influence of nursery soil compaction, composed of peat (90%) and perlite (10%), on the growth of seedlings of Pinus sylvestris grown in containers. Polyethylene nursery are containers used for the seedling production. These containers were filled with three different densities of the peat and perlite substrate (0.3, 0.5 and 0.7 g·cm-3). During the experiment, nursery containers were initially placed in a plastic tent for a period of two months, and then for three months further months in an open nursery field. Growth measurements for individual plants were the length of shoots and the root system, root collar diameter, root and shoot dry weight and photosynthetic rate. There was a relationship between the extent of compaction of the soil substrate and all analyzed growth parameters of seedlings. A more compact substrate adversely affected on the number of grown seedlings and their length but positively influenced the dry mass of pine seedlings.


2018 ◽  
Vol 33 (1) ◽  
pp. 196-201
Author(s):  
Robert Andrew Kerr ◽  
Lambert B. McCarty ◽  
William C. Bridges ◽  
Matthew Cutulle

AbstractGoosegrass is a weedy C4species throughout the world and a major pest in turfgrass systems. Further research is needed to characterize morphological events of goosegrass germinating in late summer to enhance long-term management programs. The objective of this study was to determine whether goosegrass germinating on August 15 will complete a life cycle before the first killing frost, typically November 15 in Clemson, SC. A biotype from Clemson, SC, was collected and a growth-chamber experiment was conducted to simulate autumn maximum and minimum temperatures. Culm, leaf, root, and raceme biomass measurements were recorded weekly, and growth curves were modeled. The inflection point (i.e., point of maximum growth) occurred for the following growth parameters: culm dry weight at 26.5 d after emergence (DAE), leaf dry weight at 26.6 DAE, number of racemes per plant at 50.7 DAE, raceme dry weight (including germinable seed) at 56.0 DAE, and root dry weight at 42.1 DAE. The completion of the life cycle occurred on October 22 (68 DAE), approximately 3 wk before the typical first killing frost in Clemson, SC. In summary, turf managers need to address goosegrass that germinates through approximately the first week of September at this location to avoid production of viable seed.


1991 ◽  
Vol 21 (8) ◽  
pp. 1288-1291 ◽  
Author(s):  
Christian P. Andersen ◽  
William E. Hogsett ◽  
Rose Wessling ◽  
Milton Plocher

Storage carbohydrates are extremely important for new shoot and root development following dormancy or during periods of high stress. The hypothesis that ozone decreases carbohydrate storage and decreases new root growth during the year following exposure was investigated. Ponderosa pine seedlings (Pinusponderosa Dougl. ex Laws.) exposed to ozone in 1989 were harvested prior to shoot elongation (nongrowing seedlings) and following a root growth test (growing seedlings) in the spring of 1990 to evaluate starch and soluble sugar concentrations. Seedlings exposed to the highest ozone level had 34% less lateral root biomass and 65% less new root biomass the following spring. Exposure to 122 and 169 ppm-h (sum of hourly means, 24 h/day, over the exposure period) during the 1989 growing season resulted in significant decreases of carbohydrate pools examined in both nongrowing and growing seedlings the following spring. Starch concentrations were most affected: at the highest ozone level, there were decreases of 43 and 44% in coarse and fine roots, respectively, of nongrowing seedlings, and 50, 65, and 62% in coarse, fine, and new roots, respectively, of growing seedlings. The results suggest that (i) ponderosa pine seedlings exposed to 122 and 169 ppm-h ozone for one season have significantly less root starch reserves available just prior to and during bud break the following year and (ii) spring root growth is decreased following ozone exposure. The carry-over effects of ozone stress may be important in long-lived perennial species that are annually subjected to ozone.


HortScience ◽  
1996 ◽  
Vol 31 (5) ◽  
pp. 744d-744
Author(s):  
Doug Findley ◽  
Gary J. Keever ◽  
Arthur H. Chappelka ◽  
Charles H. Gilliam ◽  
D. Joseph Eakes

Five cultivars of buddleia, Buddleia davidii, were exposed to subambient, ambient, and twice-ambient levels of ozone in open-top chambers for 8 weeks during 1995. Plants were evaluated for foliar injury, growth index, and inflorescence characteristics during and following the exposure period. Destructive harvests were conducted at the end of the exposure period to determine the dry weight of both above- and below-ground plant components. All cultivars showed signs of visible injury in the twice-ambient treatment at both 3 and 8 weeks after treatment initiation (WAT). At 3 WAT, `Pink Delight' was the most severely injured, followed by `Opera'. The other three cultivars had similar lower levels of foliar injury. Reductions in growth index as well as dry weight were found for all cultivars in the twice-ambient treatment. The number of developing floral buds and inflorescences was reduced in the twice-ambient treatment for all cultivars. Differences among the cultivars was due to normal differences in growth habit and not due to elevated ozone levels. These data indicate that Buddleia cultivars are sensitive to levels of ozone similar to those found in urban areas of the southeastern United States.


2020 ◽  
Vol 13 (2) ◽  
pp. 83-92 ◽  
Author(s):  
A. Adam

SummaryEnhancement of the resistance level in plants by rhizobacteria has been proven in several pathosystems. This study investigated the ability of four rhizobacteria strains (Pseudomonas putida BTP1 and Bacillus subtilis Bs2500, Bs2504 and Bs2508) to promote the growth in three barley genotypes and protect them against Cochliobolus sativus. Our results demonstrated that all tested rhizobacteria strains had a protective effect on barley genotypes Arabi Abiad, Banteng and WI2291. However, P. putida BTP1 and B. subtilis Bs2508 strains were the most effective as they reduced disease incidence by 53 and 38% (mean effect), respectively. On the other hand, there were significant differences among the rhizobacteria-treated genotypes on plant growth parameters, such as wet weight, dry weight, plant height and number of leaves. Pseudomonas putida BTP1 strain was the most effective as it significantly increased plant growth by 15-32%. In addition, the susceptible genotypes Arabi Abiad and WI2291 were the most responsive to rhizobacteria. This means that these genotypes have a high potential for increase of their resistance against the pathogen and enhancement of plant growth after the application of rhizobacteria. Consequently, barley seed treatment with the tested rhizobacteria could be considered as an effective biocontrol method against C. sativus.


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