Rest break in Norway spruce seedlings: test of a dynamic temperature response hypothesis

1994 ◽  
Vol 24 (3) ◽  
pp. 558-563 ◽  
Author(s):  
Heikki Hänninen ◽  
Riitta Backman
Keyword(s):  
Norway Spruce ◽  
Temperature Response ◽  
Rest Period ◽  
Simulation Models ◽  
Population Variation ◽  
Bud Burst ◽  
Dynamic Temperature ◽  
Rest Break ◽  
Chilling Period ◽  
Further Development

A hypothesis concerning a dynamic temperature response of rate of rest break was tested using a chilling experiment with three northern provenances of 2-year-old seedlings of Norway spruce (Piceaabies (L.) Karst.). According to the hypothesis, (i) within-population variation exists in the higher threshold for the rest-breaking temperature range and (ii) the higher threshold shifts towards lower temperatures as a result of chilling. The hypothesis was supported by experimental results. The results also indicated that at the beginning of the chilling period the higher threshold is a few degrees above 10 °C in the examined seedling populations. Two conventional theories about the rest period of the trees were unable to explain the observed results. The results facilitate further development of simulation models of rest break and bud burst of the trees.

scholarly journals Seasonality and competition select for variable germination behavior in perennials

2022 ◽  
Author(s):  
Hanna ten Brink ◽  
Thomas Ray Haaland ◽  
Oystein Hjorthol Opedal
Keyword(s):  
Simulation Models ◽  
Population Variation ◽  
Priority Effects ◽  
Bet Hedging ◽  
Environmental Predictability ◽  
Hedging Strategies ◽  
Unpredictable Environments ◽  
Evolutionary Simulation ◽  
Negative Frequency Dependent Selection ◽  
Germination Timing

The common occurrence of within-population variation in germination behavior and associated traits such as seed size has long fascinated evolutionary ecologists. In annuals, unpredictable environments are known to select for bet-hedging strategies causing variation in dormancy duration and germination strategies. Variation in germination timing and associated traits is also commonly observed in perennials, and often tracks gradients of environmental predictability. Although bet-hedging is thought to occur less frequently in long-lived organisms, these observations suggest a role of bet-hedging strategies in perennials occupying unpredictable environments. We use complementary numerical and evolutionary simulation models of within- and among-individual variation in germination behavior in seasonal environments to show how bet-hedging interacts with density dependence, life-history traits, and priority effects due to competitive differences among germination strategies. We reveal substantial scope for bet-hedging to produce variation in germination behavior in long-lived plants, when "false starts" to the growing season results in either competitive advantages or increased mortality risk for alternative germination strategies. Additionally, we find that two distinct germination strategies can evolve and coexist through negative frequency-dependent selection. These models extend insights from bet-hedging theory to perennials and explore how competitive communities may be affected by ongoing changes in climate and seasonality patterns.

scholarly journals Brief history and future of animal simulation models for science and application

2014 ◽  
Vol 54 (12) ◽  
pp. 1883 ◽  
Author(s):  
J. L. Black
Keyword(s):  
Animal Models ◽  
Real Time ◽  
Dynamic Models ◽  
Management Strategies ◽  
Simulation Models ◽  
Real Time Control ◽  
Livestock Farming ◽  
Animal Metabolism ◽  
The Impact ◽  
Further Development

Mathematical equations have been used to add quantitative rigour to the description of animal systems for the last 100 years. Initially, simple equations were used to describe the growth of animals or their parts and to predict nutrient requirements for different livestock species. The advent of computers led to development of complex multi-equation, dynamic models of animal metabolism and of the interaction between animals and their environment. An understanding was developed about how animal systems could be integrated in models to obtain the most realistic prediction of observations and allow accurate predictions of as yet unobserved events. Animal models have been used to illustrate how well animal systems are understood and to identify areas requiring further research. Many animal models have been developed with the aim of evaluating alternative management strategies within animal enterprises. Several important gaps in current animal models requiring further development are identified: including a more mechanistic representation of the control of feed intake; inclusion of methyl-donor requirements and simulation of the methionine cycle; plus a more mechanistic representation of disease and the impact of microbial loads under production environments. Reasons are identified why few animal models have been used for day-to-day decision making on farm. In the future, animal simulation models are envisaged to function as real-time control of systems within animal enterprises to optimise animal productivity, carcass quality, health, welfare and to maximise profit. Further development will be required for the integration of models that run real time in enterprise management systems adopting precision livestock farming technologies.

Use of sensor-determined behaviours to develop algorithms for pasture intake by individual grazing cattle

2017 ◽  
Vol 68 (12) ◽  
pp. 1091 ◽  
Author(s):  
P. L. Greenwood ◽  
D. R. Paull ◽  
J. McNally ◽  
T. Kalinowski ◽  
D. Ebert ◽  
...  
Keyword(s):  
Simulation Models ◽  
Classification Model ◽  
Pasture Management ◽  
Concentrate Supplementation ◽  
Grazing Cattle ◽  
Sensor Devices ◽  
Measurement Units ◽  
Using Data ◽  
Prediction And Simulation ◽  
Further Development

Practical and reliable measurement of pasture intake by individual animals will enable improved precision in livestock and pasture management, provide input data for prediction and simulation models, and allow animals to be ranked on grazing efficiency for genetic improvement. In this study, we assessed whether pasture intake of individual grazing cattle could be estimated from time spent exhibiting behaviours as determined from data generated by on-animal sensor devices. Variation in pasture intake was created by providing Angus steers (n = 10, mean ± s.d. liveweight 650 ± 77 kg) with differing amounts of concentrate supplementation during grazing within individual ryegrass plots (≤0.22 ha). Pasture dry matter intake (DMI) for the steers was estimated from the slope (kg DM day–1) of the regression of total pasture DM per plot on intake over an 11-day period. Pasture DM in each plot, commencing with ≤2 t DM ha–1, was determined by using repeatedly calibrated pasture height and electronic rising plate meters. The amounts of time spent grazing, ruminating, walking and resting were determined for the 10 steers by using data from collar-mounted, inertial measurement units and a previously developed, highly accurate, behaviour classification model. An initial pasture intake algorithm was established for time spent grazing: pasture DMI (kg day–1) = –4.13 + 2.325 × hours spent grazing (P = 0.010, r2 = 0.53, RSD = 1.65 kg DM day–1). Intake algorithms require further development, validation and refinement under varying pasture conditions by using sensor devices to determine specific pasture intake behaviours coupled with established methods for measuring pasture characteristics and grazing intake and selectivity.

scholarly journals Anatomy and morphology in developing vegetative buds on detached Norway spruce branches in controlled conditions before bud burst

2009 ◽  
Vol 29 (11) ◽  
pp. 1457-1465 ◽  
Author(s):  
S. Sutinen ◽  
J. Partanen ◽  
A. Vihera-Aarnio ◽  
R. Hakkinen
Keyword(s):  
Norway Spruce ◽  
Bud Burst ◽  
Controlled Conditions ◽  
Vegetative Buds

Effects of climatic change on trees from cool and temperate regions: an ecophysiological approach to modelling of bud burst phenology

1995 ◽  
Vol 73 (2) ◽  
pp. 183-199 ◽  
Author(s):  
Heikki Hänninen
Keyword(s):  
Air Temperature ◽  
Elevated Temperatures ◽  
Day Treatment ◽  
Strong Support ◽  
Frost Damage ◽  
Minor Effect ◽  
Bud Burst ◽  
Natural Conditions ◽  
Short Day ◽  
Rest Break

A framework is presented for modelling bud burst phenology of trees from the cool and temperate regions. Three ecophysiological aspects affecting the timing of bud burst are considered: (i) effects of environmental factors on the rest status of the bud, (ii) effect of rest status on the ability for bud burst, and (iii) direct effect of air temperature on the rate of development towards bud burst. Any model for bud burst phenology can be presented within the framework with three submodels, each of them addressing one of the corresponding three ecophysiological aspects. A total of 96 hypothetical models were synthesized by combining submodels presented in the literature. The models were tested in two experiments with saplings of Pinus sylvestris L. growing in experimental chambers at their natural site in eastern Finland. In the first experiment, air temperature and (or) concentration of atmospheric CO2 was elevated. Elevation of the air temperature hastened bud burst, whereas elevation of the concentration of CO2 did not affect it. Several models accurately predicted the timing of bud burst for natural conditions but too early for bud burst at the elevated temperatures. This finding suggests that (i) the risk of a premature bud burst with subsequent frost damage, as a result of climatic warming, was overestimated in a recent simulation study, and (ii) bud burst observations in natural conditions alone are not sufficient for the testing of these mechanistic models. Several models did predict the timing of bud burst accurately for all treatments, but none of them obtained sufficiently strong support from the findings to stand out as superior or uniquely correct. In the second experiment a photoperiod submodel for rest break was tested by exposing the saplings to short-day conditions. The short-day treatment had only a minor effect on the timing of bud burst. These results demonstrated the importance of the concept of model realism: the accuracy of a model can be lost in new conditions (e.g., global warming), unless the model correctly addresses the essential ecophysiological aspects of the regulation of timing of bud burst. Key words: annual cycle of development, chilling, dormancy, field test, photoperiod, rest break.

Bud burst in Norway spruce (Picea abies): preliminary evidence for age-specific rest patterns

Trees ◽  
2004 ◽  
Vol 19 (1) ◽  
pp. 66-72 ◽  
Author(s):  
Jouni Partanen ◽  
Heikki H�nninen ◽  
Risto H�kkinen
Keyword(s):  
Picea Abies ◽  
Norway Spruce ◽  
Preliminary Evidence ◽  
Bud Burst

Does the temperature response of rest break of woody plants change during the development?

1988 ◽  
Vol 18 (2) ◽  
pp. 269-271 ◽  
Author(s):  
Heikki Hänninen ◽  
Paavo Pelkonen
Keyword(s):  
Ambient Temperature ◽  
Preliminary Data ◽  
Woody Plants ◽  
Temperature Response ◽  
Breaking Effect ◽  
Temperature Conditions ◽  
Rest Break ◽  
Breaking Mechanism

Preliminary data concerning rest break of buds of 2-year-old seedlings of Pinussylvestris L. and Piceaabies (L.) Karst suggested that (i) an ambient, temperature of 12 °C has a slight rest breaking effect, and (ii) the ability of the rest breaking mechanism to respond to 12 °C is gradually lost when the seedlings are first chilled near 0 °C. This change in the response is interpreted to represent the acclimation of the seedlings to prevailing temperature conditions. A very long forcing period is required to obtain the pattern found by us.

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