Drought and simulated deer herbivory reduce growth in Atlantic white cedar seedlings

Botany ◽  
2017 ◽  
Vol 95 (5) ◽  
pp. 531-538 ◽  
Author(s):  
Janet C. Steven ◽  
Amber L. Gaddis
Keyword(s):  
Water Stress ◽  
Water Availability ◽  
Plant Biomass ◽  
Belowground Biomass ◽  
Plant Size ◽  
Potential Interaction ◽  
Shoot Biomass ◽  
Natural Habitats ◽  
White Cedar ◽  
Atlantic White Cedar

White-tailed deer are overabundant in much of eastern North America and may be suppressing regeneration in some tree species. Herbivory initially reduces plant biomass, but it has the potential to stimulate compensatory growth. However, stressful environmental conditions may reduce recovery from herbivory. Seedlings of Atlantic white cedar, Chamaecyparis thyoides (L.) Britton, Sterns & Poggenb., are frequently browsed by white-tailed deer and also experience both flooded and dry soils in natural habitats. We conducted a growth chamber experiment to test for a potential interaction between simulated deer browsing and water availability treatments on seedling height, stem diameter, and above- and belowground biomass. Of the 180 study plants, half were subjected to an initial clipping treatment, and all plants were then exposed to high, intermediate, or low water availability for 90 days. We found that, over the short term, seedlings in favorable growing conditions could not compensate for lost biomass after simulated browsing. Drought reduced shoot biomass, and flooded soils reduced root but not shoot growth. Water stress and herbivory did not interact to reduce growth more than the effect of each treatment separately. In general, the effect of water stress on plant size was greater than the effect of simulated herbivory.

scholarly journals Phenotypic response to soil compaction varies among genotypes and correlates with plant size in sorghum

2022 ◽  
Author(s):  
José Correa ◽  
Johannes A. Postma ◽  
Tobias Wojciechowski
Keyword(s):  
Soil Compaction ◽  
Crop Production ◽  
Plant Biomass ◽  
Plant Size ◽  
Adaptive Plasticity ◽  
Shoot Biomass ◽  
Adaptation Mechanism ◽  
Fine Root Length ◽  
Shoot Size ◽  
Sorghum Genotypes

Abstract Aims Soil compaction is a major yield-reducing factor worldwide and imposes physico-chemical constraints to plant growth and development. Facing limitations, roots can adapt and compensate for loss of functioning through their plasticity. Being primarily a belowground challenge, tolerance to soil compaction needs to be associated with root phenotype and plasticity. It is therefore of importance to distinguish between size-related apparent and size-independent adaptive plasticity. We determined the above- and belowground plasticity of sorghum genotypes varying in overall plant size. Methods We quantified plasticity as the degree response (adaptive and apparent plasticity) to soil compaction and conducted two experiments with sorghum and two soil density levels (1.4 and 1.8 Mg m−3). First, we quantified the shoot biomass plasticity of 28 sorghum genotypes. Second, we studied the root plasticity of six genotypes varying in shoot size and tolerance to soil compaction. Results Plasticity was correlated with plant biomass with larger genotypes responding earlier and more intensely. Soil compaction affected roots more than shoots and plasticity was expressed foremost in nodal root number and fine root length. Impeded plants produced 35 and 47% less root mass and length, respectively. Conclusions Plasticity to soil compaction varies among genotypes, but less-sensitive lines are in general smaller-sized genotypes. The association between tolerance and plant biomass may pose challenges to crop production; however, vigorous genotypes with unresponsive shoots to soil compaction do exist. Maintaining shoot growth relatively stable while the root modifies its structure can be an important adaptation mechanism to soil compaction.

scholarly journals Glyphosate Resistance in Perennial Ryegrass (Lolium perenneL.) is Associated with a Fitness Penalty

Weed Science ◽  
2016 ◽  
Vol 64 (1) ◽  
pp. 71-79 ◽  
Author(s):  
Marcos Yanniccari ◽  
Martín Vila-Aiub ◽  
Carolina Istilart ◽  
Horacio Acciaresi ◽  
Ana M. Castro
Keyword(s):  
Perennial Ryegrass ◽  
Water Availability ◽  
Field Experiments ◽  
Seed Mass ◽  
Selection Effect ◽  
Glyphosate Resistance ◽  
Shoot Biomass ◽  
Seed Number ◽  
Fitness Costs ◽  
Weed Species

The net selection effect of herbicides on herbicide-resistance traits in weeds is conditioned by the fitness benefits and costs associated with resistance alleles. Fitness costs play an important evolutionary role preventing the fixation of adaptive alleles and contributing to the maintenance of genetic polymorphisms within populations. Glyphosate is widely used in world agriculture, which has led to the evolution of widespread glyphosate resistance in many weed species. The fitness of glyphosate-resistant and -susceptible perennial ryegrass plants selected from within a single population were studied in two field experiments conducted during 2011 and 2012 under different soil water availability. Glyphosate-resistant plants showed a reduction in height of 12 and 16%, leaf blade area of 16 and 33%, shoot biomass of 45 and 55%, seed number of 33 and 53%, and total seed mass of 16 and 5% compared to glyphosate-susceptible plants in 2011 and 2012, respectively. The reduction in seed number per plant resulted in a 40% fitness cost associated with the glyphosate-resistance trait in perennial ryegrass. Fitness costs of glyphosate-resistant plants were expressed under both conditions of water availability. These results could be useful for designing management strategies and exploiting the reduced glyphosate-resistant perennial ryegrass fitness in the absence of glyphosate selection.

scholarly journals How downstream sub-basins depend on upstream inflows to avoid scarcity: typology and global analysis of transboundary rivers

2018 ◽  
Vol 22 (5) ◽  
pp. 2795-2809 ◽  
Author(s):  
Hafsa Ahmed Munia ◽  
Joseph H. A. Guillaume ◽  
Naho Mirumachi ◽  
Yoshihide Wada ◽  
Matti Kummu
Keyword(s):  
Water Stress ◽  
Water Use ◽  
Water Availability ◽  
Water Scarcity ◽  
Management Practices ◽  
Global Analysis ◽  
Water Shortage ◽  
River Basins ◽  
Analytical Framework ◽  
Available Water

Abstract. Countries sharing river basins are often dependent upon water originating outside their boundaries; meaning that without that upstream water, water scarcity may occur with flow-on implications for water use and management. We develop a formalisation of this concept drawing on ideas about the transition between regimes from resilience literature, using water stress and water shortage as indicators of water scarcity. In our analytical framework, dependency occurs if water from upstream is needed to avoid scarcity. This can be diagnosed by comparing different types of water availability on which a sub-basin relies, in particular local runoff and upstream inflows. At the same time, possible upstream water withdrawals reduce available water downstream, influencing the latter water availability. By developing a framework of scarcity and dependency, we contribute to the understanding of transitions between system regimes. We apply our analytical framework to global transboundary river basins at the scale of sub-basin areas (SBAs). Our results show that 1175 million people live under water stress (42 % of the total transboundary population). Surprisingly, the majority (1150 million) of these currently suffer from stress only due to their own excessive water use and possible water from upstream does not have impact on the stress status – i.e. they are not yet dependent on upstream water to avoid stress – but could still impact on the intensity of the stress. At the same time, 386 million people (14 %) live in SBAs that can avoid stress owing to available water from upstream and have thus upstream dependency. In the case of water shortage, 306 million people (11 %) live in SBAs dependent on upstream water to avoid possible shortage. The identification of transitions between system regimes sheds light on how SBAs may be affected in the future, potentially contributing to further refined analysis of inter- and intrabasin hydro-political power relations and strategic planning of management practices in transboundary basins.

scholarly journals Modelling global water stress of the recent past: on the relative importance of trends in water demand and climate variability

2011 ◽  
Vol 15 (12) ◽  
pp. 3785-3808 ◽  
Author(s):  
Y. Wada ◽  
L. P. H. van Beek ◽  
M. F. P. Bierkens
Keyword(s):  
Water Stress ◽  
Climate Variability ◽  
Water Use ◽  
Extreme Events ◽  
Water Availability ◽  
Water Scarcity ◽  
Water Demand ◽  
Developing Economies ◽  
Blue Water ◽  
Global Population

Abstract. During the past decades, human water use has more than doubled, yet available freshwater resources are finite. As a result, water scarcity has been prevalent in various regions of the world. Here, we present the first global assessment of past development of water stress considering not only climate variability but also growing water demand, desalinated water use and non-renewable groundwater abstraction over the period 1960–2001 at a spatial resolution of 0.5°. Agricultural water demand is estimated based on past extents of irrigated areas and livestock densities. We approximate past economic development based on GDP, energy and household consumption and electricity production, which are subsequently used together with population numbers to estimate industrial and domestic water demand. Climate variability is expressed by simulated blue water availability defined by freshwater in rivers, lakes, wetlands and reservoirs by means of the global hydrological model PCR-GLOBWB. We thus define blue water stress by comparing blue water availability with corresponding net total blue water demand by means of the commonly used, Water Scarcity Index. The results show a drastic increase in the global population living under water-stressed conditions (i.e. moderate to high water stress) due to growing water demand, primarily for irrigation, which has more than doubled from 1708/818 to 3708/1832 km3 yr−1 (gross/net) over the period 1960–2000. We estimate that 800 million people or 27% of the global population were living under water-stressed conditions for 1960. This number is eventually increased to 2.6 billion or 43% for 2000. Our results indicate that increased water demand is a decisive factor for heightened water stress in various regions such as India and North China, enhancing the intensity of water stress up to 200%, while climate variability is often a main determinant of extreme events. However, our results also suggest that in several emerging and developing economies (e.g. India, Turkey, Romania and Cuba) some of past extreme events were anthropogenically driven due to increased water demand rather than being climate-induced.

scholarly journals Unexpected relationships between δ13C and wine grape performance in organic farming

OENO One ◽  
2013 ◽  
Vol 47 (4) ◽  
pp. 269 ◽  
Author(s):  
Edoardo Antonio Costantino Costantini ◽  
Alessandro Agnelli ◽  
Pierluigi Bucelli ◽  
Aldo Ciambotti ◽  
Valentina Dell’Oro ◽  
...  
Keyword(s):  
Water Stress ◽  
Water Potential ◽  
Soil Water ◽  
Organic Farming ◽  
Water Availability ◽  
Stress Conditions ◽  
Soil Water Availability ◽  
Wine Grape ◽  
Stem Water Potential ◽  
Stem Water

<p style="text-align: justify;"><strong>Aim</strong>: To evaluate the relationship between carbon isotope ratio (δ<sup>13</sup>C) and wine grape viticultural and oenological performance in organic farming.</p><p style="text-align: justify;"><strong>Methods and results</strong>: The study was carried out for four years in the Chianti Classico wine production district (Central Italy), on five non irrigated vineyards conducted in organic farming. The reference variety was Sangiovese. Eleven sites were chosen for vine monitoring and grape sampling. The performance parameters were alcohol and must sugar content, sugar accumulation rate, mean berry weight, and extractable polyphenols. δ<sup>13</sup>C, stem water potential, and soil water availability were also monitored. Finally, soil nitrogen as well as yeast available nitrogen in the must were measured. δ<sup>13</sup>C was directly related to stem water potential and soil water deficit, and indicated a range of water stress conditions from none and moderate to strong. However, its relationship with viticultural and oenological results was contrary to expectation, that is, performance linearly increased along with soil moisture. On the other hand, the worst performance was obtained where both water and nitrogen were more limiting.</p><p style="text-align: justify;"><strong>Conclusions</strong>: The unexpected relationship between δ<sup>13</sup>C and Sangiovese performance was caused by low nitrogen availability. The studied sites all had low-fertility soils with poor or very poor nitrogen content. Therefore, in the plots where soil humidity was relatively higher, nitrogen plant uptake was favoured, and Sangiovese performance improved. Macronutrient being the main limiting factor, the performance was not lower in the plots where soil water availability was relatively larger. Therefore, the best viticultural result was obtained with no water stress conditions, at low rather than at intermediate δ<sup>13</sup>C values.</p><p style="text-align: justify;"><strong>Significance and impact of the study</strong>: Water nutrition is crucial for wine grape performance. δ<sup>13</sup>C is a method used to assess vine water status during the growing season and to estimate vine performance. A good performance is expected at moderate stress and intermediate δ<sup>13</sup>C values. A better knowledge of the interaction between water and nutrient scarcity is needed, as it can affect the use of δ<sup>13</sup>C to predict vine performance.</p>

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