Photoperiod influences dehardening of Chamaecyparisnootkatensis seedlings

1993 ◽  
Vol 23 (11) ◽  
pp. 2452-2454 ◽  
Author(s):  
B.J. Hawkins ◽  
S.E. McDonald
Keyword(s):  
Significant Influence ◽  
Electrolyte Leakage ◽  
Frost Hardiness ◽  
Controlled Environment

In early January, seedlings of yellow cypress (Chamaecyparisnootkatensis (D. Don) Spach) were placed in controlled-environment chambers under constant, increasing, and decreasing photoperiods. Seedlings from all treatments were assessed for frost hardiness at 2-week intervals using the freeze-induced electrolyte leakage method. Seedlings subject to increasing day lengths began to deharden immediately and at a greater rate than seedlings under a constant photoperiod. Seedlings in the decreasing photoperiod treatment maintained maximum hardiness for 42 days and then began to deharden spontaneously, although photoperiod continued to decrease. Once dehardening began in this treatment, it proceeded at the fastest rate of all treatments. These results indicate that photoperiod has a significant influence on the initiation and rate of dehardening in yellow cypress, and maximum hardiness cannot be maintained indefinitely.

Photoperiod and night frost influence the frost hardiness of Chamaecyparisnootkatensis clones

1993 ◽  
Vol 23 (7) ◽  
pp. 1408-1414 ◽  
Author(s):  
B.J. Hawkins
Keyword(s):  
Electrolyte Leakage ◽  
Frost Hardiness ◽  
Relative Influence ◽  
Controlled Environment ◽  
Rooted Cuttings ◽  
Subzero Temperatures ◽  
Controlled Environments

Frost hardiness in yellow cypress (Chamaecyparisnootkatensis (D. Don) Spach) was studied over the winter to determine the relative influence of photoperiod and subzero temperatures on the hardening and dehardening processes. Stecklings (rooted cuttings) of five clones from each of three provenances were grown outdoors and in two controlled-environment chambers at 10:5 °C day:night temperatures and 12- or 6-h photoperiods. Half of the plants in each photoperiod treatment were subject to a 4-h night frost, three times per week from December through to March. Frost hardiness was assessed at intervals using the freeze-induced electrolyte leakage method. Variability in frost hardiness was greater among clones within provenances than among provenances. Significant differences in hardiness among clones existed throughout the experiment; however, the ranking of clones by hardiness was not consistent. Stecklings in the 6-h photoperiod were consistently more hardy than their counterparts subjected to 12-h photoperiods. Stecklings placed outdoors had equivalent hardiness to those in the 6-h photoperiod until the advent of natural frosts in January. At this time, the outdoor trees were the most hardy. Night frost also significantly increased frost hardiness in stecklings in controlled environments. Stecklings in all treatments began to deharden between January and March. The outdoor plants dehardened most rapidly. Stecklings in the controlled environments dehardened slowly until the night-frost treatment ended, whereupon previously frozen plants dehardened more rapidly than their unfrozen counterparts.

A comparison of analytical approaches for assessing freezing damage in black spruce using electrolyte leakage methods

1996 ◽  
Vol 74 (6) ◽  
pp. 952-958 ◽  
Author(s):  
K. D. Odlum ◽  
T. J. Blake
Keyword(s):  
Critical Temperature ◽  
Electrolyte Leakage ◽  
Black Spruce ◽  
Frost Hardiness ◽  
Initial Increase ◽  
Cool Temperature ◽  
Freezing Damage ◽  
Intact Seedling ◽  
Temperature Hardening ◽  
Analytical Approaches

To compare different methods of quantifying shoot frost damage during controlled plant freezing tests, frost hardening of black spruce (Picea mariana (Mill.) BSP) seedlings exposed to three temperature hardening regimes over 16 weeks was assessed using electrolyte leakage and intact seedling methods. Electrolyte leakage was expressed as index of injury and was quantified either as the temperature needed to induce an index of injury of 5% (DT5) or as the critical temperature (CT), the mildest temperature at which damage was first detected statistically. Damage to intact shoots was expressed as percent shoot browning and was quantified as the temperature at which 50% of needle tissue on the shoots was damaged (sLT50) or as the temperature at which 50% of terminal buds were killed (bLT50). Seedling response to hardening temperature varied, depending on the method used to quantify frost hardiness. When expressed as critical temperature, hardening continued over the 16 weeks at a constant rate with no differences detected between treatments. Intact seedling shoot damage, sLT50 and bLT50, described a hardening process in which there was a large initial increase in hardening in the first 8 weeks, with less hardening occurring during the subsequent 8 weeks. Also, significant temperature effects were detected, with the greatest hardening occurring in a cool temperature (4 °C), the least in a warm temperature (20 °C), and an intermediate amount in a moderate temperature (10 °C). When quantified as DT5, the pattern of hardening was somewhat intermediate to the other two. Methods of determining frost hardiness were highly correlated, with the strongest correlation being between sLT50 and bLT50 (r2 = 0.903). Both electrolyte leakage methods, DT5 and CT, were linearly related to one another (r2 = 0.666) and were more sensitive than the intact seedling methods, since they both detected damage at warmer temperatures. DT5 was better correlated to intact measures of hardiness than was CT. Keywords: black spruce, index of injury, frost hardiness, critical temperature, damaging temperature, LT50.

Effect of population, environment, and maturation on the frost hardiness of yellow-cedar (Chamaecyparisnootkatensis)

1994 ◽  
Vol 24 (5) ◽  
pp. 945-953 ◽  
Author(s):  
B.J. Hawkins ◽  
J. Russell ◽  
R. Shortt
Keyword(s):  
Air Temperature ◽  
Electrolyte Leakage ◽  
High Elevation ◽  
Genetic Component ◽  
Frost Hardiness ◽  
Diverse Populations ◽  
Rooted Cuttings ◽  
Stock Types

Three 2-year-old experimental plantations of yellow-cedar (Chamaecyparisnootkatensis (D. Don) Spach.) seedlings and stecklings (rooted cuttings) from 4- and 12-year-old hedges were analyzed periodically for frost hardiness between September 1991 and May 1992. The plantations were at different elevations and latitudes, and seedlings and stecklings of three geographically diverse populations were represented. Frost hardiness was assessed using the freeze-induced electrolyte leakage method on upper, primary branches. Air temperature at the low elevation sites was monitored. Frost hardiness of all plants increased from September to the end of January, and then decreased. Plants grown at high elevation were consistently more hardy than those grown at low elevation; however, no obvious differences in hardiness between the two latitudes were evident. Seedlings and stecklings of parents from certain families and populations developed greater hardiness than stock of parents from other areas, showing that frost hardiness of yellow-cedar plants has a genetic component. The three stock types did not show any consistent, significant differences in hardiness; however, stecklings from 12- and 4-year-old hedges were, on average, slightly more hardy than seedlings.

scholarly journals Physiological disturbances promoted by ozone in five cultivars of Phaseolus vulgaris L.

2009 ◽  
Vol 21 (4) ◽  
pp. 319-329 ◽  
Author(s):  
Cláudia C. Clebsch ◽  
Armando M. Divan Junior ◽  
Paulo L. Oliveira ◽  
Márcio Nicolau
Keyword(s):  
Phaseolus Vulgaris ◽  
Tropospheric Ozone ◽  
Electrolyte Leakage ◽  
Ambient Air ◽  
Controlled Environment ◽  
Phaseolus Vulgaris L ◽  
Crop Species ◽  
Net Assimilation ◽  
Conclusive Data

Bean seedlings of Fepagro 26, Guapo Brilhante, Iraí, Macotaço and US Pinto 111 cultivars were submitted to treatments with or without addition of ozone to the ambient air, in order to evaluate the effects of exposure on photosynthesis, relative electrolyte leakage, foliar abscission and biomass of the seedlings. Exposure to ozone caused significant decreases in the net assimilation of all cultivars except Iraí. It also caused a significant increase in electrolyte leakage from the Pinto cultivar, but only when AOT40 was the highest. It also produced significant anticipation in the time of foliar abscission in the Pinto, Fepagro and Guapo cultivars. The variability observed in the biomass measurements reflected the limitations to perform long-term controlled-environment studies, one of the major challengers yet to be overcome in order to obtain more conclusive data on damages induced on crop species resulting from tropospheric ozone enrichment.

Effect of Photoperiod, Night Temperature, and Frost Incidence on Development of Frost Hardiness in Pinus radiata

1982 ◽  
Vol 9 (3) ◽  
pp. 333 ◽  
Author(s):  
DH Greer ◽  
IJ Warrington
Keyword(s):  
Pinus Radiata ◽  
Frost Hardiness ◽  
Late Winter ◽  
Controlled Environment ◽  
Night Temperature ◽  
Specific Effects ◽  
Critical Photoperiod ◽  
Simulated Climate ◽  
Temperature Hardening

The role of photoperiod, night temperature, and frequency and severity of frosts on the development of frost hardiness in seedlings of Pinus radiata was studied using controlled environment treatments. In one experiment the specific effects of 9 and 14 h photoperiods and 5 and 15°C night temperatures were examined. In a second experiment, seedlings were sequentially hardened under two simulated early autumn to late winter climates, with the photoperiod and day/night temperatures progressively altered at 11 and 21 day intervals respectively. In addition, half of the seedlings raised in each simulated climate were exposed concurrently to a conditioning frost regime. Frost hardiness of the seedlings in each sequence was determined at regular intervals using a series of evaluation frosts. Frosts of between -3 and -5°C were the most effective factor in controlling the development of frost hardiness. Night temperatures as low as 1°C were also effective but not those above 5°C. A minimum photoperiod requirement of less than 11 h for up to 42 days exposure was required for low-temperature hardening. There appeared to be a response lag in the development of frost hardiness once the critical photoperiod and inductive night temperatures had been imposed. Differences between nursery sites in frost hardiness of seedling stock were attributed to differences in their environments, particularly the incidence of frosts. The final maximum frost hardiness varied between the treatments from - 7.5 to -19°C indicating that Pinus radiata has a greater potential to develop frost hardiness than was previously thought from field observations.

Inbreeding effects on the spring frost hardiness of coastal Douglas-fir

1996 ◽  
Vol 26 (6) ◽  
pp. 1049-1054 ◽  
Author(s):  
R.L. Shortt ◽  
B.J. Hawkins ◽  
J.H. Woods
Keyword(s):  
Electrolyte Leakage ◽  
Common Ancestor ◽  
Visual Assessment ◽  
Douglas Fir ◽  
Assessment Methods ◽  
Frost Hardiness ◽  
Spring Frost ◽  
Consistent Relationship ◽  
The Common ◽  
Inbreeding Level

An experiment was designed to investigate the effect of inbreeding on frost hardiness of coastal Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco var. menziesii). Frost hardiness of branch samples from 19 families of Douglas-fir (four inbreeding levels within five common ancestor groups) was assessed using freeze-induced electrolyte leakage and visual assessment methods in February and April 1993. Frost hardiness of clones of the common ancestors was assessed again in February 1994 using the freeze-induced electrolyte leakage method. There was a significant correlation between the results of the two methods of frost hardiness assessment. Neither method showed a consistent relationship between frost hardiness and inbreeding level, and within-family variability in hardiness was high. Significant differences in hardiness among the common ancestor groups were evident.

scholarly journals The study of multivariance in realization of the plum graft and rootstock combinations adaptivity systems to the changing conditions of environment in the Krasnodar region with the use of digital technologies

2021 ◽  
Vol 34 ◽  
pp. 01002
Author(s):  
Irina Dragavtseva ◽  
Anna Kuznetsova ◽  
Igor Savin ◽  
Anna Klyukina
Keyword(s):  
Significant Influence ◽  
Digital Technologies ◽  
Climatic Conditions ◽  
Frost Hardiness ◽  
Efficient Allocation ◽  
Flower Buds ◽  
Yielding Capacity ◽  
Krasnodar Region ◽  
Plum Varieties ◽  
Climate Fluctuation

The study of rootstocks group, providing the average vigor of growth for the grafted fruit plants, discovered their significant influence on the frost hardiness of the “graft-rootstock” system. The adaptivity of the plum varieties in the different graft and rootstock combinations was studied according to the “frost hardiness” criterion in the stages of the winter and spring development of the flower buds. The computer maps of the plum efficient allocation were created on the studied rootstocks, permitting to lay down the plantings with the lesser risks in the terms of climate fluctuation. It was established, that in the south of Russia the climatic conditions to cultivate Stanley variety on PK SK 1 rootstock, as compared with the rootstock of cherry plum seedling, mostly often used in industrial plantings of plum are mostly favorable. The conducted research contributes to isolation and allocation of the most adaptive graft and rootstock combinations based on their frost hardiness and, consequently, regularity of fruit-bearing and yielding capacity.

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