Ethylene and ethane evolution during cold acclimation and deacclimation of ponderosa pine

1991 ◽  
Vol 21 (5) ◽  
pp. 601-605 ◽  
Author(s):  
Karen E. Burr ◽  
Stephen J. Wallner ◽  
Richard W. Tinus

Greenhouse container-grown ponderosa pine (Pinusponderosa var. scopulorum Engelm.) were cold acclimated and deacclimated in growth chambers during a 19-week regime. Seedling cold hardiness, bud dormancy, and ethylene and ethane evolution from excised needles were measured weekly. Ethylene and ethane evolution and the ethane/ethylene ratio declined from bud set to bud break and did not parallel changes in cold hardiness. Large standard errors of the ethylene evolution means made detecting statistical differences over time difficult. Significant deviations in the ethane evolution means were observed, however, and indicated a sharp decrease and recovery at the start of cold acclimation and a peak at the start of deacclimation. The ethane/ethylene ratio accentuated the declining trend from bud set to bud break and the two sharp deviations in the trend at the start of acclimation and deacclimation.

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1085c-1085
Author(s):  
Karen E. Burr ◽  
Stephen J. Wanner ◽  
Richard W. Tinus

It is not known when changes in primary direct heat stress tolerance of conifer seedlings occur in relation to other seasonally changing physiological parameters. This information should be incorporated into nursery practices and the matching of genotypes to landscape sites. Greenhouse-cultured, container-grown Douglas-fir, Engelmann spruce, and ponderosa pine. were cold acclimated and reacclimated in growth chambers over 19 weeks. Direct heat stress tolerance of needles, cold hardiness, and bud dormancy were measured weekly. Douglas-fir and Engelmann spruce heat stress tolerance increased with the development of new growth through one complete growth cycle, i.e., bud break, maturation, cold hardening, dehardening, and bud break the following growing season. Ponderosa pine differed in that new needles had intermediate tolerance, and fully cold hardy needles were the most intolerant. In none of the species did the timing of changes in heat stress tolerance coincide consistently with changes in cold hardiness or bud dormancy.


2008 ◽  
Vol 255 (11) ◽  
pp. 3672-3676 ◽  
Author(s):  
Arnulfo Aldrete ◽  
J.G. Mexal ◽  
Karen E. Burr

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 548f-549
Author(s):  
Sunghee Guak ◽  
Lailiang Cheng ◽  
Leslie H. Fuchigami

Bench-grafted `Gala'/M26 apple trees were grown in pots and fertigated weekly with 150 ppm N starting from 10 May. N supply was terminated on 21 Aug., 18 Sept., and 9 Oct. for the early, mid, and late N cut-off treatment, respectively. Half of the trees in the early N cut-off treatment were sprayed twice with 3% urea at 6-day intervals in early October. Half of the trees in the mid and late N cut-off treatment were sprayed twice with 1000 ppm ABA at 5-day intervals in early and mid-October, respectively. Early N cut-off significantly enhanced terminal bud set, defoliation, and induction of cold acclimation compared to the late N cut-off. Foliar urea increased the reserve N level in all tissues of the early N cut-off trees, almost to the level of late N cut-off trees. Soluble protein concentrations were increased by foliar urea, which accounted for about 23%, 10%, and 17% of the increase in the total N concentration in bark, wood, and roots, respectively. ABA treatment enhanced leaf senescence and N mobilization in the mid and late N cut-off trees, but did not affect terminal bud set and cold hardiness.


2010 ◽  
Vol 28 (4) ◽  
pp. 235-239
Author(s):  
Frank P. Henning ◽  
Timothy J. Smalley ◽  
Orville M. Lindstrom ◽  
John M. Ruter

Abstract Plants that maintain their leaves throughout winter may respond differently to fall fertilization than deciduous plants. The effects of fall fertilization on cold hardiness, nutrient uptake, growth and flower production of evergreen versus deciduous azaleas were studied. Rhododendron canescens (Michx.) Sweet and R. × satsuki ‘Wakaebisu’ were grown in containers, outdoors in Athens, GA, under three fall fertigation regimes applied daily as 0.5 liter (0.13 gal) solutions containing: 1) 75 mg·liter−1 N from August 1 through September 29, 2) 75 mg·liter−1 N from August 1 through November 28, and 3) 125 mg·liter−1 N from August 1 through November 28. Stem freeze resistance was analyzed monthly November through March. Growth of azaleas that received 120 days of extended fertigation (August 1 through November 28) was not increased compared to azaleas that received 60 days of extended fertigation (August 1 through September 29). Growth of the two taxa did not differ in their response to fertilization treatments. The high rate of extended fertilization 125 mg·liter−1 N (from August 1 through November 28) reduced stem freeze resistance November through February, while the moderate rate of extended fertilization (75 mg·liter−1 N from August 1 through November 28) reduced azalea freeze resistance in December. Fall fertilization regimes did not produce differences in the timing of cold acclimation, or deacclimation of R. canescens and R. × satsuki. The high rate of extended fertilization promoted early budbreak of R. × satsuki and postponed flower budbreak of R. canescens. Flower production of R. canescens was not affected by fall fertilization, but the high rate of extended fertilization increased flower production of R. × satsuki compared to plants that received the moderate rate of fertilization 75 mg·liter−1 N from August 1 through September 29.


1977 ◽  
Vol 7 (4) ◽  
pp. 614-620 ◽  
Author(s):  
Eric Young ◽  
James W. Hanover

Blue spruce (Piceapungens Engelm.) seedlings grown in a nursery for 1 to 5 years and seedlings grown from seed in a greenhouse under continuous light for 2 to 6 months were studied to determine (1) time to bud set on transfer to short days, (2) time to bud-break on subsequent transfer to long days, and (3) the anatomy of the dormant shoot apex. Seasonal development of the shoot apex of a single 50-year-old blue spruce was also monitored.Time to but set on transfer to short days decreased after long periods under continuous light. Time to budbreak on subsequent transfer to long days increased with increasing age in nursery- and greenhouse-grown seedlings. The dormant shoot apex became more highly differentiated as the nursery-grown seedlings aged from 1 to 3 years, then showed no significant difference after 3 years of age.The 50-year-old blue spruce initiated many new needles in the current bud before bud scale formation, which began in mid-May. Needle primordia initiation in the new bud began in late June and slowed down in late August. Apical dome diameter increased and decreased concurrently with the increase and decrease in rate of needle primordia initiation.


2000 ◽  
Vol 77 (11) ◽  
pp. 1648-1654
Author(s):  
Laura A Hyatt ◽  
Ann S Evans ◽  
Carol C Baskin

Patterns of germination over time were investigated in a short-lived desert perennial species, Lesquerella fendleri (Gray) S. Wats. Field-collected seeds were either buried in the field in cloth bags or stored in a glass jar under laboratory conditions. Regular germination tests were conducted under a range of alternating temperatures (buried seeds) or under differing water regimes (laboratory-stored seeds). Testing revealed Lesquerella fendleri to have an annual dormancy-nondormancy cycle, which was manifest regardless of seed storage conditions, suggesting that cycles may be partially endogenously regulated. Increasing seed germinability in field-stored seeds (maximum of 30% in year 1 and 95% in year 2) leads to the formation of a seed bank for at least 1 year and enhances the possibility of spreading germination events through time. This allows parent plants to maximize fitness in randomly fluctuating environments. The existence of two seedling flushes in the field and single germinability peaks in growth chambers suggests that dormancy cycling may support the formation of a metapopulation with subpopulations which are, although physically intermingled, genetically distinct.


Forests ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 834
Author(s):  
Harold S. J. Zald ◽  
Becky K. Kerns ◽  
Michelle A. Day

Fire exclusion has dramatically altered historically fire adapted forests across western North America. In response, forest managers reduce forest fuels with mechanical thinning and/or prescribed burning to alter fire behavior, with additional objectives of restoring forest composition, structure, and ecosystem processes. There has been extensive research on the effects of fuel reduction and restoration treatments on trees, fuels, regeneration, and fire behavior; but less is known about how these treatments influence understory vegetation, which contains the majority of vascular plant diversity in many dry conifer forests. Of particular interest is how understory vegetation may respond to the season and interval of prescribed burning. The season and interval of prescribed burning is often determined by operational constraints rather than historical fire regimes, potentially resulting in fire conditions and burn intervals to which native plants are poorly adapted. In this study, we examined how understory vegetation has responded to season and interval of prescribed burning in ponderosa pine (Pinus ponderosa) forests in the Blue Mountains of northeastern Oregon, USA. Using over a decade (2002–2015) of understory vegetation data collected in stands with different intervals (5 versus 15 year) and seasons (spring versus fall) of prescribed burning, we quantified how season and interval of prescribed burning has influenced understory vegetation compositional trajectories and indicator species over time. Season of prescribed burning resulted in different understory communities and distinct trajectories of understory composition over time, but interval of burning did not. Indicator species analysis suggests fall burning is facilitating early seral species, with native annual forbs displaying ephemeral responses to frequent burning, while invasive cheatgrass (Bromus tectorum) increased in abundance and frequency across all treatments over time. These findings indicate that understory vegetation in these ecosystems are sensitive to seasonality of burning, but the responses are subtle. Our findings suggest season and interval of prescribed burning used in this study do not result in large changes in understory vegetation community composition, a key consideration as land managers increase the pace and scale of prescribed fire in these forests.


2020 ◽  
Author(s):  
Kensuke Kimura ◽  
Daisuke Yasutake ◽  
Takahiro Oki ◽  
Koichiro Yoshida ◽  
Masaharu Kitano

Abstract Background and Aims Most perennial plants memorize cold stress for a certain period and retrieve the memories for cold acclimation and deacclimation, which leads to seasonal changes in cold-hardiness. Therefore, a model for evaluating cold stress memories is required for predicting cold-hardiness and for future frost risk assessments under warming climates. In this study we develop a new dynamic model of cold-hardiness by introducing a function imitating past temperature memory in the processes of cold acclimation and deacclimation. Methods We formulated the past temperature memory for plants using thermal time weighted by a forgetting function, and thereby proposed a dynamic model of cold-hardiness. We used the buds of tea plants (Camellia sinensis) from two cultivars, ‘Yabukita’ and ‘Yutakamidori’, to calibrate and validate this model based on 10 years of observed cold-hardiness data. Key Results The model captured more than 90 % of the observed variation in cold-hardiness and predicted accurate values for both cultivars, with root mean square errors of ~1.0 °C. The optimized forgetting function indicated that the tea buds memorized both short-term (recent days) and long-term (previous months) temperatures. The memories can drive short-term processes such as increasing/decreasing the content of carbohydrates, proteins and antioxidants in the buds, as well as long-term processes such as determining the bud phenological stage, both of which vary with cold-hardiness. Conclusions The use of a forgetting function is an effective means of understanding temperature memories in plants and will aid in developing reliable predictions of cold-hardiness for various plant species under global climate warming.


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