**5. Methodology**

**4. Global changes and plants: a perspective of stoichiometric scaling**

nutrient composition of the ecosystem and increase the risk of extinction of species.

There is strong evidence on the relationship between atmospheric CO2

plant stoichiometry. It is expected that the increases of atmospheric CO2

plant photosynthesis and, perhaps, growth and overall production.

the resources available in the soil, particularly N [62].

**4.1. Atmospheric CO2**

156 Plant Ecology - Traditional Approaches to Recent Trends

Atmospheric CO2

higher levels of CO2

**4.2. Global warming**

carbon [62].

diverted to increase production [68].

and increases in plant size [69].

In general, a higher concentration of CO2

Global changes can affect the stoichiometry of plants and of the ecosystem through changes in C:P and C:N ratios, which can alter food quality, affect the nutrient cycle, impoverish the

As a result, there is potential for C sequestration in plant biomass as atmospheric CO2 increases [61]. However, the length of plant growth in any location is probably influenced by

will influence the C:N:P ratios of the entire plant and, ultimately, photosynthetic capacity [65]. At the molecular level, rubisco, a key photosynthetic enzyme, operates more efficiently at

ing the need for gene expression of the enzyme to compensate for the losses to photorespira‐ tion [67]. The resources (for example, N) which are not used to produce rubisco can then be

Global warming will likely influence plant stoichiometry, plant species, community primary

However, these effects will be moderated by drought. For example, in the long term, warming with increasing drought conditions in the Amazon can induce massive changes in biomass

However, restrictions on the use of nutrients [45] and changes in development and the way plants share resources across the types of tissue [70] suggest changes in C concentrations on a large scale; they will also be accompanied by absolute changes in levels of soil nutrients.

The majority of terrestrial ecosystems has historically been adapted to a natural limitation of key nutrients [71]. Combustion of fossil fuels, use of fertilizers, agricultural production of legumes [72], deforestation and changes in land [73] allowed for a large‐scale duplication of input of biologically available N in ecosystems around the world. The anthropogenic effects

production through impacts on phenology and plant growth conditions [61].

**4.3. Varying increases in supplementation with N and P**

fixation tends to increase the root/plant ratio [63] and leaf area [64], which

emissions (intracellular levels), especially in C3 plants [66], by minimiz‐

should result in a greater C:N ratio in plant biomass

concentration and

will stimulate the

Data from the published literature on the ecological response to global change were collected: C:N:P stoichiometry changes in plant environmental adaptations. The information on the cli‐ matic effect of latitude was obtained from information on variation in N:P (molar ratio) in foliage (open triangles) and litter (solid diamonds) as a function of latitude [23].

Regarding the light climatic factor, data were selected and collected on differences in the exposure of plants to sunlight that can affect plant stoichiometry. This study was based on the work of Valladares et al. [26].

Regarding the dry climatic factor, the information collection was made considering that the effects of the water deficit differed between ecosystems and species, based on scientific stud‐ ies [30–35].

For the climate heating factor, information on the effect of temperature, respiratory responses to heating and on cold ecosystems the effects of heating on the C:N ratios [38–41] were addressed.

The variations in the C:N:P ratios in plants were plotted from the collection of information on growth rate and N:P stoichiometry in plants that were based primarily on works of [42, 43], and plant stoichiometry in the information collected mainly from the work of [49, 50, 55, 58].

Finally, global and plant changes: a perspective of stoichiometric design, atmospheric CO2 was studied; Global warming and variable increases in N and P supplementation, from the collection of relevant information, based on published scientific articles on the subject.
