Responses of black spruce seedlings to simulated present versus future seedbed environments

1995 ◽  
Vol 25 (4) ◽  
pp. 545-554 ◽  
Author(s):  
Zhang Ming Wang ◽  
Martin J. Lechowicz ◽  
Catherine Potvin
Keyword(s):  
Biomass Allocation ◽  
Nitrogen Availability ◽  
Seedling Survival ◽  
Dry Mass ◽  
Future Climate ◽  
Nitrogen Use ◽  
Seedling Performance ◽  
Bud Development ◽  
The Future ◽  
Allocation Patterns

We investigated the effects of nitrogen availability and present versus future atmospheric environments (i.e., climate) on the seedling performance of 16 open-pollinated maternal families of Piceamariana (Mill.) B.S.P. over two simulated growing seasons. Diurnal and seasonal patterns of temperature, relative humidity, photoperiod, and light intensity were simulated. The simulated future climate included both elevated CO2 and seasonally appropriate increases in mean monthly temperatures. Compared with the present, the future climate increased seedling survival, total and root dry mass, rate of winter bud development, net photosynthetic rate, and water and nitrogen use efficiencies; decreased needle nitrogen content; and altered biomass allocation patterns. Greater nitrogen availability greatly improved seedling performance and changed biomass allocation patterns. Climate and nitrogen level interacted synergistically to promote seedling growth (branch number and root dry mass), survival, and bud development. The future climate increased seedling survival, rate of bud development, and nitrogen use efficiency much more in the low than in the high nitrogen regime. Seedling performance in the second season was dependent on initial seed mass, but less than in the 1st year. Some of the differences among the families and in their interactions with the climate and (or) nitrogen fertilization suggest that families selected for rapid growth under present conditions may not do well in the future, at least in terms of early establishment. Forest managers and tree breeders should take this possibility into consideration in their tree improvement and reforestation programs.

Nitrogen fixation makes biomass allocation to roots independent of soil nitrogen supply

2007 ◽  
Vol 85 (9) ◽  
pp. 787-793 ◽  
Author(s):  
John H. Markham ◽  
Corinthe Zekveld
Keyword(s):  
Nitrogen Fixation ◽  
Plant Growth ◽  
Biomass Allocation ◽  
Soil Nitrogen ◽  
Nitrogen Availability ◽  
Nitrogen Concentration ◽  
Nitrogen Fixing ◽  
Soil Nitrogen Availability ◽  
Least Squares Fit ◽  
Allocation Patterns

Biomass allocation patterns in plants are known to be affected by soil nitrogen availability. Since nitrogen availability can depress symbiotic nitrogen fixation, and nitrogen fixation can make plant growth independent of soil nitrogen availability but is energetically costly, it is unclear how allocation patterns in nitrogen-fixing species should respond to variation in soil nitrogen availability. We examined the effect of nitrogen source and concentration on the growth and allocation patterns in the nitrogen-fixing shrub Alnus viridis subsp. crispa (Aiton) Turrill. Plants were grown with either NH4+-N or NO3–-N at a range of low N concentrations, from 0 to 2 mmol·L–1, and either inoculated with Frankia or not. Plants without nodules had 25.l% lower biomass and had double the allocation to roots at all but the 2 mmol·L–1 nitrogen concentration. Even though nodulated plants increased growth with nitrogen concentration, allocation to roots as a fraction of total biomass did not vary in these plants, suggesting increased growth resulted from more efficient nitrogen acquisition. Allocation to roots was a significant predictor of plant growth in non-nodulated plants (r2 = 0.318, for linear least squares fit with log mass) but not for nodulated plants (r2 = 0.108). As nitrogen concentrations increased, allocation to nodules, specific nodule numbers, and the proportion of nitrogen fixed by the plants decreased, demonstrating a shift to soil nitrogen use.

How the future climate may modulate the non-breeding distribution of a Vulnerable gadfly petrel

2018 ◽  
Vol 599 ◽  
pp. 253-266
Author(s):  
L Krüger ◽  
JM Pereira ◽  
I Ramírez ◽  
JA Ramos ◽  
VH Paiva
Keyword(s):  
Future Climate ◽  
Breeding Distribution ◽  
The Future

scholarly journals Adaptation Mechanism of Roots to Low and High Nitrogen Revealed by Proteomic Analysis

Rice ◽  
2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Wei Xin ◽  
Lina Zhang ◽  
Jiping Gao ◽  
Wenzhong Zhang ◽  
Jun Yi ◽  
...  
Keyword(s):  
Root Growth ◽  
Nitrogen Use Efficiency ◽  
Root Morphology ◽  
Nitrogen Availability ◽  
Rice Root ◽  
Global Changes ◽  
High Nitrogen ◽  
Nitrogen Use ◽  
Rice Roots ◽  
Use Efficiency

Abstract Background Nitrogen-based nutrients are the main factors affecting rice growth and development. Root systems play an important role in helping plants to obtain nutrients from the soil. Root morphology and physiology are often closely related to above-ground plant organs performance. Therefore, it is important to understand the regulatory effects of nitrogen (N) on rice root growth to improve nitrogen use efficiency. Results In this study, changes in the rice root traits under low N (13.33 ppm), normal N (40 ppm) and high N (120 ppm) conditions were performed through root morphology analysis. These results show that, compared with normal N conditions, root growth is promoted under low N conditions, and inhibited under high N conditions. To understand the molecular mechanism underlying the rice root response to low and high N conditions, comparative proteomics analysis was performed using a tandem mass tag (TMT)-based approach, and differentially abundant proteins (DAPs) were further characterized. Compared with normal N conditions, a total of 291 and 211 DAPs were identified under low and high N conditions, respectively. The abundance of proteins involved in cell differentiation, cell wall modification, phenylpropanoid biosynthesis, and protein synthesis was differentially altered, which was an important reason for changes in root morphology. Furthermore, although both low and high N can cause nitrogen stress, rice roots revealed obvious differences in adaptation to low and high N. Conclusions These results provide insights into global changes in the response of rice roots to nitrogen availability and may facilitate the development of rice cultivars with high nitrogen use efficiency through root-based genetic improvements.

scholarly journals How will future climate depending agronomic management impact the yield risk of wheat cropping systems? A regional case study of Eastern Denmark

2021 ◽  
pp. 1-16
Author(s):  
J. Macholdt ◽  
J. Glerup Gyldengren ◽  
E. Diamantopoulos ◽  
M. E. Styczen
Keyword(s):  
Climate Change ◽  
Crop Production ◽  
Cropping Systems ◽  
Future Climate ◽  
Catch Crops ◽  
Agronomic Management ◽  
The Future ◽  
Yield Risk ◽  
Management Factors ◽  
The Impact

Abstract One of the major challenges in agriculture is how climate change influences crop production, for different environmental (soil type, topography, groundwater depth, etc.) and agronomic management conditions. Through systems modelling, this study aims to quantify the impact of future climate on yield risk of winter wheat for two common soil types of Eastern Denmark. The agro-ecosystem model DAISY was used to simulate arable, conventional cropping systems (CSs) and the study focused on the three main management factors: cropping sequence, usage of catch crops and cereal straw management. For the case region of Eastern Denmark, the future yield risk of wheat does not necessarily increase under climate change mainly due to lower water stress in the projections; rather, it depends on appropriate management and each CS design. Major management factors affecting the yield risk of wheat were N supply and the amount of organic material added during rotations. If a CS is characterized by straw removal and no catch crop within the rotation, an increased wheat yield risk must be expected in the future. In contrast, more favourable CSs, including catch crops and straw incorporation, maintain their capacity and result in a decreasing yield risk over time. Higher soil organic matter content, higher net nitrogen mineralization rate and higher soil organic nitrogen content were the main underlying causes for these positive effects. Furthermore, the simulation results showed better N recycling and reduced nitrate leaching for the more favourable CSs, which provide benefits for environment-friendly and sustainable crop production.

scholarly journals A simulation study on the effect of climate change on crop water use and chill unit accumulation

2017 ◽  
Vol 113 (7/8) ◽  
Author(s):  
Abiodun A. Ogundeji ◽  
Henry Jordaan
Keyword(s):  
Climate Change ◽  
Water Resources ◽  
Water Use ◽  
Irrigation System ◽  
Future Climate ◽  
Crop Water ◽  
Crop Water Use ◽  
Chill Unit ◽  
The Future ◽  
The Impact

Climate change and its impact on already scarce water resources are of global importance, but even more so for water scarce countries. Apart from the effect of climate change on water supply, the chill unit requirement of deciduous fruit crops is also expected to be affected. Although research on crop water use has been undertaken, researchers have not taken the future climate into consideration. They also have focused on increasing temperatures but failed to relate temperature to chill unit accumulation, especially in South Africa. With a view of helping farmers to adapt to climate change, in this study we provide information that will assist farmers in their decision-making process for adaptation and in the selection of appropriate cultivars of deciduous fruits. Crop water use and chill unit requirements are modelled for the present and future climate. Results show that, irrespective of the irrigation system employed, climate change has led to increases in crop water use. Water use with the drip irrigation system was lower than with sprinkler irrigation as a result of efficiency differences in the irrigation technologies. It was also confirmed that the accumulated chill units will decrease in the future as a consequence of climate change. In order to remain in production, farmers need to adapt to climate change stress by putting in place water resources and crop management plans. Thus, producers must be furnished with a variety of adaptation or management strategies to overcome the impact of climate change.

scholarly journals Regionalization of Climate Change Simulations over the Eastern Mediterranean

2009 ◽  
Vol 22 (8) ◽  
pp. 1944-1961 ◽  
Author(s):  
Bariş Önol ◽  
Fredrick H. M. Semazzi
Keyword(s):  
Climate Change ◽  
Regional Climate Model ◽  
Temperature Increase ◽  
Climate Model ◽  
Eastern Mediterranean ◽  
Regional Climate ◽  
Future Climate ◽  
Climate Change Projections ◽  
Model Simulations ◽  
The Future

Abstract In this study, the potential role of global warming in modulating the future climate over the eastern Mediterranean (EM) region has been investigated. The primary vehicle of this investigation is the Abdus Salam International Centre for Theoretical Physics Regional Climate Model version 3 (ICTP-RegCM3), which was used to downscale the present and future climate scenario simulations generated by the NASA’s finite-volume GCM (fvGCM). The present-day (1961–90; RF) simulations and the future climate change projections (2071–2100; A2) are based on the Intergovernmental Panel on Climate Change (IPCC) greenhouse gas (GHG) emissions. During the Northern Hemispheric winter season, the general increase in precipitation over the northern sector of the EM region is present both in the fvGCM and RegCM3 model simulations. The regional model simulations reveal a significant increase (10%–50%) in winter precipitation over the Carpathian Mountains and along the east coast of the Black Sea, over the Kackar Mountains, and over the Caucasus Mountains. The large decrease in precipitation over the southeastern Turkey region that recharges the Euphrates and Tigris River basins could become a major source of concern for the countries downstream of this region. The model results also indicate that the autumn rains, which are primarily confined over Turkey for the current climate, will expand into Syria and Iraq in the future, which is consistent with the corresponding changes in the circulation pattern. The climate change over EM tends to manifest itself in terms of the modulation of North Atlantic Oscillation. During summer, temperature increase is as large as 7°C over the Balkan countries while changes for the rest of the region are in the range of 3°–4°C. Overall the temperature increase in summer is much greater than the corresponding changes during winter. Presentation of the climate change projections in terms of individual country averages is highly advantageous for the practical interpretation of the results. The consistence of the country averages for the RF RegCM3 projections with the corresponding averaged station data is compelling evidence of the added value of regional climate model downscaling.

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