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Root Absorption and Xylem Translocation:
Root Absorption and Xylem Translocation Introduction
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Plant roots and below ground shoots have few barriers to herbicide absorption; however, interactions with soil particles and soil organic matter have significant impacts on the amount of herbicide available for plant absorption. Plant roots and below ground shoots (hypocotyls or coleoptiles) are lipophilic by nature and do not have thick, waxy cuticles like leaves. Lipophilic and hydrophilic herbicides reach the root surface by bulk transport in soil water; however, there are a few examples of herbicides that reach the root as a vapor or gas. Soil-applied herbicides can translocate to the shoot or remain in the root system. Soil-applied herbicides translocate to the shoot in the xylem and tend to accumulate in mature leaves that transpire the most water. The lipophilic/hydrophilic nature of the herbicide will determine if the herbicide translocates to the shoot.
At the completion of this lesson, learners will understand the following principles: - Soil characteristics such as % clay, % organic, and pH influence herbicide availability.
- Chemical characteristics of the herbicide influence root absorption.
- Chemical characteristics of the herbicide also influence herbicide anslocation to the shoot.
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