EIACP Centre on Plants and Pollution

Role of Plants in CO₂ Sequestration

Introduction

Source: https://cargocollective.com/AndrewPenn/Nano-Particles-Nano-Robotics

Carbon sequestration means capturing carbon dioxide (CO₂) from the atmosphere or capturing anthropogenic (human) CO₂ from large-scale stationary sources like power plants before it is released to the atmosphere. Once captured, the CO₂ gas (or the carbon portion of the CO₂) is put into long-term storage. CO₂ sequestration has the potential to significantly reduce the level of carbon that occurs in the atmosphere as CO₂ and to reduce the release of CO₂ to the atmosphere from major stationary human sources, including power plants and refineries. There are two major types of CO₂ sequestration: terrestrial and geologic.

Terrestrial

Terrestrial (or biologic) sequestration means using plants to capture CO₂ from the atmosphere and then storing it as carbon in the stems and roots of the plants as well as in the soil.

Geologic

Geologic sequestration is the method of storage that is generally considered for carbon capture and storage (CCS) projects. CCS is the practice of capturing CO₂ at anthropogenic sources before it is released to the atmosphere and then transporting the CO₂ gas to a site where it can be put into long-term storage. (Pacala & Socolow 2004).

Source: Pacala, S., and Socolow, R., 2004, Stabilization wedges-solving the climate problem for the next 50 years with current technologies: Science, v. 305, p. 968-972.

Possible functional role of root exudate components in the rhizosphere¹⁰

Component	Rhizosphere function
Phenolics	Nutrient source
	Chemo-attractant signals to microbes
	Microbial growth promoters
	Nod gene inducers in rhizobia
	Nod gene inhibiters in rhizobia
	Resistance inducers against phytoalexins
	Act as chelaters
	Phytoalexin against soil pathogens
Organic acids	Nutrient source
	Chemo-attractant signals to microbes
	Chelaters of poorly soluble mineral nutrients
	Acidifiers of soils
	Detoxifiers of Al
	Nod gene inducers
Amino acids and phytosiderophores	Nutrient source
	Chemo-attractant signals to microbes
	Chelaters of poorly soluble mineral nutrients
Vitamins	Promoters of plant and microbial growth
	Nutrient source
Purines	Nutrient source
Enzymes	Catalysts for phosphorus release from organic molecules
	Biocatalyst for organic matter transformation in soil
Root border cells	Produce signals that control mitosis
	Produce signals controlling gene expression
	Stimulate microbial growth
	Release chemo-attractants
	Synthesize defence molecules for the rhizosphere
	Act as decoys that keep root cap infection-free
	Release mucilage and proteins
Sugars	Nutrient source
	Promoters of microbial growth

Source: http://www.iisc.ernet.in/~currsci/oct102016/885.pdf

Participation of Plant

Source: storiented.blogspot.com

Plants are the main source of the soil organic carbon, either from the decomposition of aerial plant parts or underground plant parts, e.g. roots in the form of root death, root exudates and root respiration. About 40% of the photosynthates synthesized in the plant parts is lost through the root system into the rhizosphere within an hour and the rate of loss is influenced by several factors, e.g. plant age, different biotic and abiotic stresses, etc. The rhizospheric environment of the plant is different compared to bulk soil with respect to physical, chemical and biological properties. Thus the aim of this article is to provide an insight on the contribution of plant roots for transfer of carbon from atmosphere to rhizosphere and further their significance in sustainable agriculture (Kumar et al., 2006).

Carbon sequestered into the soil

Source: clu-in.org

At disturbed sites, the natural processes of soil and plant cycling, respiration, and terrestrial carbon sequestration have been significantly reduced if not ceased entirely. When carbon-rich soil amendments are applied to these sites, the amendments help to jumpstart soil and plant life cycles. Soil amendments provide a high concentration of carbon to carbon-devoid land, so that it is transformed to a favorable environment for soil activity and plant growth. In addition to carbon storage in soils, the now established growth of trees and plants assimilates CO₂ from the atmosphere for photosynthesis. Plants also cycle CO₂ through their roots into the soil where it is used for soil microbial respiration and stored (i.e. sequestered). These processes lead to the reduction of greenhouse gases in the atmosphere. There is both a one-time carbon load at the time of soil amendment application, and an annual terrestrial carbon sequestration rate in the new functioning ecosystem until the carbon reaches saturation. There is also the additional benefit of carbon emission avoidance from reusing organic materials that may have been destined for a landfill and emit CO₂ and CH₄.

Forests Are Truly a Green Way to Reduce CO₂

Increasing the carbon sequestration capacity of New York's forests can be started now. DEC is working on policies and programs to encourage wider use of these strategies to increase forest carbon sequestration:

• Promote stewardship of Private Forest Land.
• Reduce unnecessary deforestation.
• Add, especially in urban areas.
• Increase the use of sustainable forest management.

The costs are comparatively low, and there are minimal environmental impacts. But the biggest advantage of increasing forests for carbon sequestration capacity is that there are so many environmental benefits from forests that it would be worth increasing them anyway - even if they weren't so effective at sequestering carbon.

Although forests alone can't sequester all of the excess carbon added by burning fossil fuels, they can make a difference, especially if we help and encourage them. Wisely managed forests can sequester carbon and also provide a sustainable source of fuel and lumber, help clean our air and water, preserve wildlife habitat, provide recreation opportunities and preserve the beauty of trees in their natural home for generations to come.

Source: http://www.dec.ny.gov/lands/47481.html