Influence of dormancy induction treatments on western hemlock seedlings. II. Physiological and morphological response during the first growing season on a reforestation site

1991 ◽  
Vol 21 (2) ◽  
pp. 175-185 ◽  
Author(s):  
S. C. Grossnickle ◽  
J. T. Arnott ◽  
J. E. Major
Keyword(s):  
Low Temperature ◽  
Root Development ◽  
Growing Season ◽  
Western Hemlock ◽  
Root Collar Diameter ◽  
Short Day ◽  
Long Day ◽  
Collar Diameter ◽  
Root Collar ◽  
Dormancy Induction

Western hemlock (Tsugaheterophylla (Raf.) Sarg.) seedlings from four dormancy induction treatments (DIT) (i.e., long-day dry, long-day wet, short-day dry, short-day wet) were planted on a coastal reforestation site in British Columbia and monitored for physiological response and morphological development over the first growing season. Seedlings in all DIT showed a similar net photosynthetic, needle conductance, and shoot water potential response to seasonal low temperature, non droughty, and late summer drought conditions. Pressure–volume analysis at the beginning of the growing season (late February) showed short-day wet seedlings to have lower saturated and turgor loss point osmotic potentials than other DIT, while at the end of the growing season (October) there was no osmotic potential difference between DIT. At the end of the growing season, short-day wet seedlings had a much lower maximum modulus of elasticity than other DIT, indicating their shoots were still elongating. Morphological assessment 1 month after field planting showed short-day DIT seedlings had less needle damage and greater root development in response to continuous low temperature exposure. Four months after planting, long-day wet seedlings had the greatest shoot (i.e., height, root collar diameter) and root development in response to mild temperatures and high soil moisture conditions. Eight months after planting, survival was between 95 and 97% for all DIT. Long-day DIT seedlings had the greatest height and all DIT had similar root collar diameter and root development. Short-day DIT seedlings had the best shoot/soil roots ratio. Short-day wet seedlings had the least number of stem units per centimetre of new shoot development throughout the growing season. Results are discussed in reference to stock quality assessment presented in the first paper of this series.

scholarly journals Morphology, Physiology, Survival, and Field Performance of Containerized Coastal Douglas Fir Seedlings Given Different Dormancy-induction Regimes

HortScience ◽  
2006 ◽  
Vol 41 (6) ◽  
pp. 1416-1420 ◽  
Author(s):  
Joanne E. MacDonald ◽  
John N. Owens
Keyword(s):  
Seedling Survival ◽  
Dry Weight ◽  
Growing Season ◽  
Moisture Stress ◽  
Root Collar Diameter ◽  
Shoot Dry Weight ◽  
Collar Diameter ◽  
Terminal Buds ◽  
Root Collar ◽  
Dormancy Induction

The effects of different dormancy-induction regimes on first-year containerized coastal Douglas fir [Pseudotsuga menziesii (Mirb.) Franco var. menziesii] seedling morphology and physiology in the nursery, as well as seedling survival and performance after one growing season in a common garden, were investigated. In early July, three dormancy-induction regimes were applied: moderate moisture stress (MS), short day (SD), and short day with moderate moisture stress (SD+MS). In early October, seedling height, root collar diameter, and shoot dry weight were unaffected by regime, but root dry weight was reduced in seedlings from the MS and SD+MS regimes compared with the SD regime. At this time, morphogenesis was completed in all terminal buds of seedlings from both SD regimes, whereas it continued in all terminal buds of seedlings from the MS regime. Furthermore, 25% to 88% of terminal buds from the SD regimes were endodormant, but none from the MS regime were endodormant. In March, budbreak occurred at the same time in seedlings from the two SD regimes and was earlier than in seedlings from the MS regime; root growth capacity was unaffected by regime. After one growing season, there were no regime differences in seedling survival, root collar diameter, shoot dry weight, root dry weight, length of the current-year leader, or number of needles on the leader.

Influence of dormancy induction treatments on western hemlock seedlings. I. Seedling development and stock quality assessment

1991 ◽  
Vol 21 (2) ◽  
pp. 164-174 ◽  
Author(s):  
S. C. Grossnickle ◽  
J. T. Arnott ◽  
J. E. Major ◽  
T. J. Tschaplinski
Keyword(s):  
Water Movement ◽  
Seedling Development ◽  
Western Hemlock ◽  
Root Temperature ◽  
Turgor Loss Point ◽  
Short Day ◽  
Long Day ◽  
Osmotic Potentials ◽  
Dormancy Induction ◽  
Needle Primordia

Western hemlock (Tsugaheterophylla (Raf.) Sarg.) seedlings were grown in a greenhouse and subjected to four dormancy induction treatments (DIT) (i.e., long-day dry, long-day wet, short-day dry, and short-day wet) during midsummer. In the late summer and fall, seedling development was monitored and it was found that (1) short-day DIT caused a rapid cessation of shoot growth; (2) short-day DIT caused rapid fall development of needle primordia, while long-day DIT took until midwinter to produce the same number of needle primordia; and (3) short-day DIT seedlings had lower saturated and turgor loss point osmotic potentials and greater maximum modulus of elasticity in October than long-day DIT. Seedlings were tested with a comprehensive stock quality assessment procedure just before late winter field planting. These tests showed the following: (1) morphological parameters: short-day DIT reduced shoot to root ratios; (2) pressure–volume analysis: short-day wet seedlings had the lowest osmotic potentials at saturation and turgor loss point; (3) soluble sugar analysis: greater levels of total soluble sugars were found in non water stressed DIT compared with water stressed DIT seedlings; (4) seedling water movement: short-day DIT seedlings had the lowest resistance to water movement at low root temperature (5 °C); (5) low root temperature response: short-day compared with long-day DIT seedlings had greater photosynthesis and stomatal conductance at low root temperatures; (6) root growth capacity: seedlings from all DIT were capable of growing roots at optimum root temperature (22 °C), but short-day compared with long-day DIT had greater root growth at low root temperatures; (7) drought stress response: short-day wet seedlings had the highest photosynthesis and stomatal conductance levels as predawn shoot water potentials decreased; and (8) frost hardiness: short-day wet seedlings had the least needle damage when tested at temperatures of −15 and −18 °C.

scholarly journals Subirrigation Effects on Larch Seedling Growth, Root Morphology, and Media Chemistry

Forests ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 38 ◽  
Author(s):  
Fangfang Wan ◽  
Amy L. Ross-Davis ◽  
Wenhui Shi ◽  
Christopher Weston ◽  
Xiehai Song ◽  
...  
Keyword(s):  
Surface Area ◽  
Root Morphology ◽  
Growing Season ◽  
Root Diameter ◽  
Fertilizer Rate ◽  
Growing Media ◽  
Root Collar Diameter ◽  
Size Classes ◽  
Collar Diameter ◽  
Root Collar

Subirrigation (SI), where water is provided to container seedlings from below and rises through the growing media via capillary action, is regarded as an environmentally-responsible method of delivering water and fertilizer to nursery-grown plants, resulting in more uniform crops and improved production efficiency. While a concern around adopting this method is that a potential higher salt concentration in the upper layers of growing media under SI may inhibit root growth and result in decreased plant quality, few studies have focused on how root morphology is altered by SI. Therefore, a balanced two-factor factorial design with three rates of fertilization (50, 100, and 150 mg N seedling−1) and two irrigation methods (SI or overhead irrigation (OI)) was used to examine the growth response of Prince Rupprecht’s larch (Larix principis-rupprechtii Mayr) seedlings for one nursery season. Associated changes between rhizosphere electrical conductivity (EC) and root morphology of different root size classes were analyzed. Results show that (1) height, root-collar diameter, and root volume were similar between seedlings grown under SI and OI. However, (2) compared to seedlings receiving OI, SI-seedlings had less root mass, length, and surface area but greater average root diameter (ARD). (3) Morphological differences were evident primarily in root diameter size classes I–III (D ≤ 1.0 mm). (4) Fertilizer rate influenced root length and surface area up to 130 days after sowing but affected ARD throughout the growing season such that seedlings treated with 50 mg N had smaller ARD than seedlings treated with 100 mg N. (5) As the growing season progressed, SI-media had significantly higher EC compared to OI-media and EC increased with increasing fertilizer rate under SI but not under OI. These results indicate that SI can produce larch seedlings of similar height and root collar diameter (RCD) compared to OI, but root systems are smaller overall with fewer small-diameter roots, which may be related to high EC levels in SI-media, which is exacerbated by the use of high rates of fertilizer. Therefore, the EC in the media should be monitored and adjusted by reducing fertilizer rates under SI.

scholarly journals Influence of nitrogen fertilisation on biometric features of two-year-old seedlings of pedunculate oak subjected for root pruning

2017 ◽  
Vol 59 (4) ◽  
pp. 281-286
Author(s):  
Maria Hauke-Kowalska ◽  
Winicjusz Kasprzyk
Keyword(s):  
Growing Season ◽  
Root Pruning ◽  
Pedunculate Oak ◽  
Seedling Morphology ◽  
Significance Level ◽  
Root Collar Diameter ◽  
Nitrogen Fertilisation ◽  
Second Growth ◽  
Collar Diameter ◽  
Root Collar

AbstractPruning is one of the important cultural treatments that have potential to influence hardwood seedling morphology. The aim of the study was to compare the growth of pedunculate oak seedlings, performed pruning roots, in the second growing season, fertilised full and reduced dose of nitrogen.A total of 24 experimental plots, each with an the area of 0.04 ha, were designated. The roots pruning were made at the end of February 2014 using root pruning machine EGEDAL. The fertilisation, for all seedlings, was performed using ammonium nitrate in an amount of 25 kg ha−1of nitrogen. The second fertilisation was performed only for variants 2 and 4. For these variants, urea was used in an amount of 25 kg ha−1. At the end of the growing season, the root collar diameter and the height of seedlings were measured.A dose of nitrogen affects the height of pruned seedlings. The effect of the full dose of nitrogen on the height of the pruned seedlings was a statistically significant (p≤ 0.05). There was no statistical difference in the height of the seedlings without pruning, fertilised with different dose of nitrogen.Analysis of root collar diameter showed the significant differences between the variants. The Tukey test, at the significance level ofp≤ 0.05, showed a significant impact on the root collar diameter of pruned seedlings but no proven effect of nitrogen fertilisation. To conclude, we found that it is reasonable to reduce the doses of nitrogen fertilisation to half of recommended amount (25 kg ha−1) if the root system is not pruned during the second growth year. Seedlings that has received pruning should be fertilised using the recommended doses of nitrogen.

scholarly journals Responses of the Physiological and Biochemical Characteristics of Alfalfa Roots with Different Root Collar Diameters to Low Temperatures Under Simulated Winter Irrigation

2021 ◽  
Author(s):  
Aimin Zhu ◽  
Qingxin Zhang ◽  
Xiaoyan Du ◽  
Xianguo Wang ◽  
Yuxia Zhang ◽  
...  
Keyword(s):  
Low Temperature ◽  
Temperature Stress ◽  
Low Temperature Stress ◽  
Sod Activity ◽  
Root Collar Diameter ◽  
Carbon And Nitrogen ◽  
Collar Diameter ◽  
Alfalfa Root ◽  
Physiological And Biochemical ◽  
Root Collar

Abstract Background: Due to the frequent occurrence of extremely low temperatures in northern China, the problem of alfalfa mortality during overwintering requires urgent solutions to support the development of large-scale alfalfa production in the region. Understanding the effects of winter irrigation and the alfalfa root collar diameter on physiological and biochemical cold resistance mechanisms in alfalfa will be of great significance to finding such solutions.Methods: In this study, alfalfa roots with different root collar diameters (3.50±0.10 mm, 5.25±0.10 mm, 7.00±0.10 mm) were subjected to simulated winter irrigation (0 ml, 20 ml, 40 ml) and different low-temperature stress treatments (4°C, -10°C, -15°C, -20°C) in the laboratory. The relationships between alfalfa root collar activity, relative conductivity and the nonstructural carbon and nitrogen contents and antioxidant enzyme activity in the collar were explored.Results: Low-temperature stress was the most important factor causing significant changes in the physiological and biochemical indexes of the alfalfa root collar, followed by the root collar diameter. Low-temperature stress and the root collar diameter had significant effects on nonstructural carbon and nitrogen levels and enzyme activity (except POD activity) in alfalfa root collars, and winter irrigation had extremely significant effects on the nonstructural nitrogen contents of alfalfa root collars. The larger the diameter of the root collar was, the higher the soluble protein content and the stronger the SOD activity. Simulated winter irrigation increased the C/N ratio in the alfalfa root collars. The increases in nonstructural carbon content, C/N ratio and SOD activity in alfalfa root collars helped improve alfalfa cold resistance.Conclusions: Alfalfa resists low-temperature stress by adjusting the proportions of nonstructural carbon and nitrogen as well as the SOD activity in the root collar. Therefore, fertilization, early sowing and other management measures should be adopted to ensure healthy alfalfa growth and thereby increase the root collar diameter of alfalfa grown in cold regions in northern China. Moreover, timely supplementary irrigation to reach soil saturation in winter can play an important role in improving cold resistance in alfalfa.

Morphological Effects of Root Pruning and Wrenching White Spruce Transplants

1988 ◽  
Vol 5 (4) ◽  
pp. 245-247
Author(s):  
Lisa J. Buse ◽  
Robert J. Day
Keyword(s):  
Growing Season ◽  
White Spruce ◽  
Shoot Elongation ◽  
Diameter Growth ◽  
Root Pruning ◽  
Fibrous Root ◽  
Root Collar Diameter ◽  
Collar Diameter ◽  
Root Collar

Abstract The principal objective of this research was to evaluate the effect of root pruning followed by wrenching on the morphological quality of 2 + 2 white spruce transplant stock during the final year on the nursery. In 1984, white spruce transplants were root pruned: (1) before shoot elongation; (2) during elongation; and (3) after elongation, followed by root wrenching at 28-day intervals until September (4, 3, and 2 times, respectively). In 1985, similar stock was root pruned before shoot elongation and (1) root wrenched at 21-day intervals (4 times), and (2) root wrenched periodically (twice). In both years, height and root collar diameter growth were monitored throughout the season. In the fall, morphological quality was assessed and bud samples were collected to determine the effects of root conditioning on primordia development. Root conditioning modified the morphology of stock in both years by reducing height and root collar diameter and inducing the development of a compact fibrous root system. Early season root pruning followed by wrenching at regular intervals throughout the growing season had the most effect on shoot and root morphology. Differences in results between years were attributed to environment. North. J. Appl. For. 5:245-247, December 1988.

scholarly journals Growth of bare root Pinus taeda, L. seedlings cultivated under five densities in nursery

2007 ◽  
Vol 64 (1) ◽  
pp. 23-29
Author(s):  
José Geraldo de Araújo Carneiro ◽  
Deborah Guerra Barroso ◽  
Luis Maurício da Silva Soares
Keyword(s):  
Pinus Taeda ◽  
Dry Matter ◽  
Root Systems ◽  
Root Collar Diameter ◽  
Plant Densities ◽  
Collar Diameter ◽  
Bare Root ◽  
Pinus Taeda L ◽  
Root Collar ◽  
Dry Matter Weight

Seedlings compete for nutrients, water and light. The available area for each seedling affects their behavior related to requirements for these resources. This experiment evaluated the influence of five plant densities on the growth of bare root Pinus taeda, L. seedlings in a nursery after outplanting. The analyzed characteristics were: height (H), root collar diameter (D), H/D ratio, and dry matter weight. Higher densities stimulated H growth and the lowest densities increased D average and dry matter weight and lowered the H/D ratio. Seedlings were distributed by H, D and H/D classes. Higher densities had a larger number of seedlings in larger H classes. Larger numbers of seedlings with larger D and lower H/D ratios were found in lower densities. Ten months after outplanting the seedlings grown in lower densities had higher survival percentages and growth. Some saplings of standardized heights were uprooted with the objective of studying their root systems. The lowest densities stimulated higher numbers of first and second order roots as well as fresh and dry matter weights of thin roots with mycorrhizae presence. In both parts of the experiment, the density of 278 seedlings m-2 yielded equivalent averages as compared to the lowest densities.

scholarly journals Growth Regulators Affect the Growth and Biochemical Activity of Curcuma longa Plants Grown in vitro

2019 ◽  
Vol 11 (10) ◽  
pp. 277 ◽  
Author(s):  
Meire Pereira de Souza Ferrari ◽  
Mayara dos Santos Queiroz ◽  
Matheus Marquezini de Andrade ◽  
Jessica Rezende Trettel ◽  
Hélida Mara Magalhães
Keyword(s):  
Antioxidant Activity ◽  
Enzymatic Activity ◽  
Growth Regulators ◽  
Curcuma Longa ◽  
Ms Medium ◽  
Biochemical Activity ◽  
Root Collar Diameter ◽  
Collar Diameter ◽  
Root Collar

This study aimed to evaluate the in vitro growth and biochemical activity of Curcuma longa explants using different MS medium formulations and growth regulators. In all the experiments, plants were grown in MS medium supplemented with agar (6.5 g L-1) and pH adjusted to 5.8. In the first assay, the MS culture medium at 70% strength, supplemented with 30 g L-1 of sucrose, and without the addition of activated carbon, resulted in the highest number of shoots. The sucrose concentration of 60 g L-1, combined with the addition of actived charcoalin half-strength MS medium, resulted in the increased root dry mass, root collar diameter, and relative chlorophyll index. In the second assay, the highest root collar diameter and dry matter of shoots and roots were found in the MS medium supplemented with 4.44 BAP, 0.46 KIN, and 1.08 NAA. The MS medium with 8.88 BAP, 0.92 KIN, and 2.16 μM NAA resulted in the highest number of shoots (7.75), number of leaves (35), and shoot length (88.57 mm). The antioxidant activity was significantly higher in the treatments that resulted in better plantlets growth performance, demonstrating that the antioxidant activity is related to other factors such as a possible role of growth regulators on the elicitation of compounds in plants. Superoxide dismutase had a high enzymatic activity in both assays, whereas the enzymatic activity of catalase and ascorbate peroxidase was dependent on the culture media used.

scholarly journals Relationship between morphological and physiological attributes of hop hornbeam seedlings

2013 ◽  
pp. 39-50 ◽  
Author(s):  
Vladan Ivetic ◽  
Zoran Davorija ◽  
Dragica Vilotic
Keyword(s):  
Potassium Concentration ◽  
Growing Season ◽  
Dry Mass ◽  
Seedling Quality ◽  
Strong Positive Correlation ◽  
Strong Correlations ◽  
Morphological Attributes ◽  
Collar Diameter ◽  
Root Collar ◽  
Ostrya Carpinifolia

Most commonly used morphological attributes were correlated with nutrient concentration in order to standardize quality assessment of two-year-old hop hornbeam (Ostrya carpinifolia Scop.) seedlings. Diameter has proven to be the best single morphological indicator of seedling quality given its strong positive correlation with all other observed morphological attributes. Seedling dry mass (shoot and root dry mass) and Dickson Quality Index can be considered the most comprehensive indicators of hop hornbeam seedling quality. However, the measuring of mass is destructive and requires a certain amount of time. The absence of strong correlations between physiological and morphological attributes of two-year old seedlings of hop hornbeam suggests the need for further research. The only significant correlation between physiological and morphological attributes (weak and positive) was recorded between the potassium concentration in root and root collar diameter after the second growing season.

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