Gibberellins and heterosis in poplar

1988 ◽  
Vol 66 (6) ◽  
pp. 1148-1152 ◽  
Author(s):  
Nicholas J. Bate ◽  
Stewart B. Rood ◽  
Terence J. Blake

To investigate the possible involvement of gibberellins (GAs) in heterosis of hybrid poplar, six poplar clones were studied, including two Populus deltoides clones and two interspecific hybrid clones (P. ×euramericana = P. deltoides × P. nigra) originating from crosses with each of the P. deltoides clones. In field conditions in Ontario, Canada, the interspecific hybrids were consistently taller and had greater shoot dry weights than their parental P. deltoides clones. Shoot dry weights and heights were highly correlated across the six clones, as clonal rankings for these parameters were identical. Endogenous GA-like substances were extracted, purified, chromatographed on silica gel partition columns, and quantified by the cv. Tan-ginbozu dwarf rice bioassay. Bioactive peaks were further chromatographed on reversed-phase C18 HPLC and again bio-assayed. Statistically significant differences in concentrations of total GA-like substances were observed. With one exception, the rankings for the concentrations of GA-like substances and those of GA1-like plus GA19-like substances were similar to the rankings for height growth. Gibberellins A1 and A19 have been identified from the tissue of hybrid poplar by capillary gas chromatography – selected ion monitoring (GC–SIM), and GA1 was also identified by GC–SIM in this tissue. In three of four comparisons, interspecific hybrids contained significantly higher concentrations of GA-like activity than their corresponding parental clones. Thus, a correlation was observed between the concentration of endogenous GA-like activity and hybrid vigor for height growth and shoot dry weight in poplar.

1993 ◽  
Vol 23 (5) ◽  
pp. 854-858 ◽  
Author(s):  
Albert Z. Tenga ◽  
Beverley Hale ◽  
Douglas P. Ormrod

Controlled-environment facilities were used to determine the growth response of hybrid poplar using concentrations and exposure frequencies of ozone (O3) that mimic ambient patterns. Young cuttings of Populusdeltoides × nigra were exposed to daily bell-shaped concentration profiles of O3 with four peak concentrations and two exposures per week for 1 to 4 weeks. Exposure to O3 initially stimulated height growth rate, but repeated exposure resulted in decreases in height growth rate. Stem diameter growth rate decreased with increasing O3 concentration. Leaf greenness decreased with repeated exposure. The rate of leaf production declined with increasing O3 concentration. Many leaves abscised in the higher O3 treatments, resulting ultimately in stimulation of bud break. Leaf area, leaf dry weight, and root dry weight at harvest decreased with increasing total O3 exposure regardless of number of exposures. Stem dry weight was greater after limited initial O3 exposure but was less after repeated O3 exposures. Repeated exposures to O3 were uniformly detrimental to poplar growth parameters.


2019 ◽  
Vol 68 (1) ◽  
pp. 58-66 ◽  
Author(s):  
Neil D. Nelson ◽  
Richard Meilan ◽  
William E. Berguson ◽  
Bernard G. McMahon ◽  
Meijun Cai ◽  
...  

Abstract Growth, clone rank, genotype x environment interaction, and effects of early fertilization and irrigation were evaluated for 56 hybrid poplar clones after three years’ growth on two agricultural sites in Indiana, USA. Forty-eight percent of the clones were Populus deltoides x P. nigra (DxN) crosses made with a female parent of Minnesota provenance, with the hybrids or female parent screened in Minnesota for survival, growth rate, and disease tolerance or resistance. Forty-one percent of the clones had at least one parent from provenances that are more southerly and/or have more moderate climates of provenance origin than Minnesota. Eleven percent of the clones were screened in Minnesota but were either not DXN crosses or did not have parents from Minnesota provenances in their parentage. Height growth averaged 1.78 m per year for all clones over all treatments and 2.02 m per year for the fastest- growing six clones (top 10th percentile). Tree bole volume for the fastest-growing 10 % of the clones was 70 % larger than the average of two commercial standard clones. The clonal effect was dominant in comparison to site, treatment, and interaction effects. The fertilizer, irrigation, and fertilizer x irrigation treatments tended to increase growth, but the statistical significance of the treatment effects differed by site, and the treatments explained only a small portion of the variance. Clone rank was the same on both sites, regardless of treatment, except for the fertilizer x irrigation treatment. DxN clones linked to Minnesota parentage out-performed most clones of more southerly or other more moderate climatic origins, in these tests conducted far south of Minnesota. The data provide further evidence of broad adaptability of DxN hybrids with female P. deltoides parents of Minnesota provenance, possibly eliminating the need for narrow breeding zones and reducing the number of screening tests needed at different latitudes, saving time and money. Tests are planned to further analyze and possibly extend this inference.


1984 ◽  
Vol 14 (6) ◽  
pp. 850-854 ◽  
Author(s):  
S. B. Rood ◽  
G. Daicos ◽  
T. J. Blake

Weekly applications of 0.4 mg gibberellic acid (GA) in 8 μL 95% ethanol micropipetted onto shoots of rooted cuttings increased Populuseuramericana (Dode) Guinier height growth by 54% and shoot dry weight by 25% after 21 days. Total leaf area increased by 21% as a result of more rapid leaf production and slightly larger leaf sizes. Root growth was unaffected by GA treatment. The observed GA-induced acceleration resulted from an increase in relative growth rate while mean net assimilation rate was unaffected. Owing to a substantial increase in the number and size of leaves, the leaf area ratio, representing the ratio of photosynthesizing to respiring material, increased. While direct micropipette application of GA promoted height growth and primary shoot dry weight accumulation, GA application through either foliar spray or soil drench also promoted the growth of secondary shoots. Application of GA to shoots was more effective in promoting shoot growth than application through the roots. Direct GA application also promoted the growth of P. alba L. × P. grandidentata Michx. and P. × canescens (Ait.) Smith × P. alba × P. grandidentata. Thus, GA can be used for hastening early growth of these trees under winter greenhouse conditions.


1984 ◽  
Vol 14 (1) ◽  
pp. 150-153 ◽  
Author(s):  
M. J. Mahoney ◽  
J. M. Skelly ◽  
B. I. Chevone ◽  
L. D. Moore

Six-week-old yellow poplar (Liriodendrontulipifera L.) seedlings from one half-sib family were exposed to various combinations of 0.07 ppm O3, 0.06 ppm SO2, and 0.10 ppm NO2 6 h daily for 35 consecutive days. Ozone and SO2 alone did not suppress total shoot elongation compared with control seedlings after the 5-week fumigation period, whereas the combinations of O3 + SO2, SO2 + NO2, or O3 + SO2 + NO2 significantly reduced total shoot height 51, 64, and 51%, respectively. Of the pollutant combinations, SO2 + NO2 most severely inhibited the rate of height growth with this effect initially occurring after only 2 weeks of fumigation. The dry weight of seedlings exposed to O3 + SO2, SO2 + NO2, or O3 + SO2 + NO2 were significantly less than plants exposed to no pollutants, O3, or SO2. Total shoot height growth was highly correlated with seedling dry weight (r = 0.97)


1985 ◽  
Vol 65 (4) ◽  
pp. 727-735 ◽  
Author(s):  
V. R. TIMMER

Unrooted hybrid poplar cuttings were grown in a greenhouse at varying soil pH. The soil was a loamy fine sand (pH 5.7) collected from an Ap horizon of a forest tree nursery. The pH was adjusted over a wide range by incorporating different rates of powdered lime or elemental sulfur. Lime additions failed to improve growth significantly over a 20-wk period, and excessive liming to pH 7.6 reduced shoot dry weight by 33%, probably because of decreased availability of micronutrients. Sulfur, acidifying the soil to pH 4.1, depressed growth as much as 76%. This growth inhibition was closely associated with increased Al in both foliage and soil as well as reduced foliar uptake of the other essential nutrients. Maximum height growth of clone DTAC-32 occurred between pH 6.0 and 7.0, which falls within the general guidelines for producing hardwood nursery stock. Key words: Populus, soil pH, aluminum toxicity, micronutrient deficiency


1989 ◽  
Vol 67 (7) ◽  
pp. 2168-2174 ◽  
Author(s):  
T. J. Tschaplinski ◽  
T. J. Blake

The relationship between the rooting patterns of five poplar hybrids and stem carbohydrate dynamics was investigated to determine if the availability or metabolism of carbohydrates was limiting early root production of cuttings. Differences in early root production (i.e., number, length, and dry weight) after 17 days paralleled the subsequent differences in accumulation of aboveground biomass that were observed when two Populus balsamifera L. × deltoides Bartr. (Jackii 4 and Jackii 7) and three Populus deltoides Bartr. × nigra L. (DN 2, DN 22, and DN 15) hybrids were compared. Total root length and dry weight of Jackii 4 was four times that of Jackii 7. Both DN 2 and DN 22 had a total root length twice that of DN 15. Rooting characteristics may be useful criteria for selection of productive clones. Carbohydrate analysis of stem cuttings suggested that hybrids differing in biomass production displayed different patterns of carbohydrate utilization. The concentrations of glucose and myoinositol declined more in faster growing hybrids (Jackii 4, DN 2, DN 22) than in slower growing hybrids (Jackii 7, DN 15). The results suggest that faster growing hybrids consume monosaccharides in growth processes, whereas the slower growing hybrids convert monosaccharides into alternative storage forms and use less in growth processes. The initial myoinositol concentration in stem cuttings of poplar hybrids was correlated (r2 = 0.95) with root dry weight produced after 17 days, but the initial starch concentration was unrelated to later root biomass production. The results suggest that initial myoinositol concentration in cuttings may be used in early selection for rooting performance.


1982 ◽  
Vol 9 (2) ◽  
pp. 68-72 ◽  
Author(s):  
D. L. Ketring ◽  
W. R. Jordan ◽  
O. D. Smith ◽  
C. E. Simpson

Abstract The shape and extent of root systems influence the rate and pattern of nutrient and water uptake from the soil. In dicotyledons such as peanut (Arachis hypogaea L.), the primary root and its laterals constitute the main root system. Rooting trait differences in some crops have been associated with drought tolerance. Our objective in this study was to determine if variation in root length and number occurs among peanut genotypes. In one test, shoot and root growth of 23 genotypes (12 spanish and 11 virginia types) were compared in the greenhouse at 55 days after planting using clear acrylic tubes 7.5 cm in diameter and 2.2 m in length. Shoot dry weight, leaf area, tap root length, and root number at 1 m depth ranged for spanish-type entries from 1.23 to 2.65 g, 214 to 409 cm2, 95.0 to 186.8 cm, and 1.0 to 3.1, respectively. Similarly, ranges for virginia-type entries were 1.35 to 3.23 g, 135 to 460 cm2, 122.4 to 192.6 cm, and 1.0 to 7.1. Correlations between shoot and root parameters indicated strong positive association between aerial and subterranean growth. However, the relationship of leaf area to root length was stronger for virginia- than for spanish-type entries. Root length and numbers were highly correlated for spanish, but not for virginia entries. In other tests that included two each of virginia-, spanish-, and valencia-type entries, similar results were found for plants at 34 and 47 days after planting. Significant differences in both root (length and numbers) and shoot growth (dry weight and leaf area) were found among the genotypes tested. Inherent differences in root growth rate were evident at early stages of seedling growth. The results from this sample of peanut germplasm indicate that there is considerable diversity in root growth and there is high shoot/root growth association.


2006 ◽  
Vol 24 (1) ◽  
pp. 18-22
Author(s):  
Donna C. Fare

Abstract Two studies were conducted to determine container size and liner (young bare root trees) trunk diameter effects on growth of Acer rubrum L. ‘Franksred’, Red Sunset™ red maple. In experiment 1, maples liners with initial mean trunk diameters of 12.2 mm (0.5 in), 15.9 mm (0.6 in), and 22.3 mm (0.9 in) were potted in 26.5 liter (#7), 37.8 liter (#10), and 56.8 liter (#15) containers and grown for 18 months (2 growing seasons). Height and trunk diameter growth at the end of each growing season were affected by both the initial liner trunk diameter and container size. During year 1, liners with an initial trunk diameter of 12.2 mm (0.5 in) increased 28 and 70% more in height growth compared to liners initially 15.9 mm (0.6 in) and 22.3 mm (0.9) in trunk diameter, respectively. Twenty three percent more height growth occurred with maples in 37.8 liter (#10) and 56.8 liter (#15) containers compared to those in 26.5 liter (#7) containers. Trunk diameter growth increased 50% more with 12.2 mm (0.5 in) liners compared to 22.3 mm (0.9 in) liners. A 25% increase in trunk diameter growth occurred with liners potted in 56.8 liter (#15) compared to 26.5 liter (#7) containers. At the end of the second growing season, final tree size was similar with liners that were initially 12.2 mm (0.5 in) and 15.9 mm (0.6 in) liners in trunk diameter to those initially 22.3 mm (0.9 in) when potted into 37.8 liter (#10) and 56.8 liter (#15) containers. In experiment 2, maple liners with trunk diameters 17.5 mm (0.7 in), 20.5 mm (0.8 in), and 29.0 mm (1.1 in) were potted in container sizes 26.5 liter (#7), 37.8 liter (#10), and 56.8 liter (#15) and grown for 18 months (2 growing seasons). Liners grown in 56.8 liter (#15) containers had 92% more height growth and 48% more trunk diameter growth than with liners in 26.5 liter (#7) containers. At termination, the shoot dry weight was 41% larger with maples in 56.8 liter (#15) containers compared to those grown in 26.5 liter (#7) containers.


HortScience ◽  
1990 ◽  
Vol 25 (12) ◽  
pp. 1609-1612
Author(s):  
Luther Waters ◽  
Bonnie L. Blanchette ◽  
Rhoda L. Burrows ◽  
David Bedford

High levels of sphagnum peat in the growing medium promoted growth of asparagus (Asparagus officinalis L. cv. Viking 2K) in a greenhouse study. Application of NH4NO3 > 1 g/pot (84 kg·ha-1 equivalent) was detrimental to root growth. High N rates and high organic matter levels decreased fibrous root development. Shoot dry weight was highly correlated with fleshy root number, root dry weight, and shoot vigor.


Forests ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 672 ◽  
Author(s):  
Ronald S. Zalesny ◽  
Craig M. Stange ◽  
Bruce A. Birr

Salt-affected soils in the Northern Great Plains, USA, can impact the long-term survival and growth of trees recommended for agroforestry systems, with Russian olive (Elaeagnus angustifolia L.) being one of few options that survives on these sites. Similarly, hybrid poplars have been used for phytotechnologies on high-salinity soils throughout the world. The objective of this study was to test the survival, height growth, and phytoextraction potential of eight hybrid poplar clones (Populus deltoides Bartr. ex Marsh. × P. nigra L. ‘Robusta’, ‘DN17’, ‘DN182’, ‘DN5’; P. deltoides × P. maximowiczii A. Henry ‘NC14104’, ‘NC14106’; P. nigra × P. maximowiczii ‘NM2’, ‘NM6’) versus Russian olive grown on soils categorized according to initial salinity levels: low (0.1 to 3.9 dS m−1), medium (4.0 to 5.9 dS m−1), and high (6.0 to 10.0 dS m−1). Seven trees per genotype were grown in each salinity treatment at a spacing of 3 × 3 m for four years in Burleigh County, North Dakota. Survival and height were determined following the first four growing seasons, and leaf phytoextraction potential of Al, Ca, Cd, Fe, K, Mg, Mn, Na, and Zn was measured for one-year-old trees. Soil salinity decreased over time, reflecting the phytoextraction potential of the trees. Russian olive did not survive as well as expected, having lower overall survival than three of the hybrid poplar clones (‘DN17’, ‘DN5’, ‘NM6’). At the end of three years when trees were removed per a landowner maintenance agreement, 86%, 71%, and 43% of the Russian olive trees were alive in the low-, medium-, and high-salinity soils, respectively. At this time, ‘NM2’ was the only hybrid poplar clone with similar survival to Russian olive in the high-salinity soils. Russian olive had greater Na, Cd, and Fe leaf concentrations than the hybrid poplar clones, but it also had the worst uptake of Ca and Mg of all genotypes. For hybrid poplar, the P. deltoides × P. nigra genomic group had the broadest clonal variability among all traits, with ‘Robusta’ and ‘DN182’ exhibiting great potential for establishment on high-salinity soils. ‘Robusta’ and ‘DN17’ are the same genotype but they came from different nursery sources (i.e., hence their different nomenclature), and they did not differ for height nor leaf phytoextraction. Populus deltoides × P. maximowiczii clones were not suitable for the soil conditions and silvicultural applications (e.g., tree shelters) of the current study, while P. nigra × P. maximowiczii clones exhibited the most stable performance across all years and salinity treatments. Both ‘NM2’ and ‘NM6’ had superior fourth-year survival and height, as well as average or above average phytoextraction of all elements tested.


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