From the Field-Agronomy Notes
Tobacco Research Update: Phosphorus Deficiency of Tobacco
In this tobacco research update, we highlight the symptoms of phosphorus deficiency. These images are part of a project supported by the North Carolina Tobacco Foundation to develop a web-based diagnostic key for the identification of nutrient disorders of tobacco.
Being one of the three primary macroelements required for plant growth, phosphorus (P) deficiency symptoms develop quickly when P is in short supply.
Phosphorus deficiency in tobacco begins as a noticeable stunting when compared to a plant with a sufficient supply of P (Fig. 1). Additionally, a P deficient tobacco plant may be more likely to develop a darker green coloration of the upper foliage. Lower leaves will become chlorotic with a mottling of olive green leaf spots (Fig. 2). The initial symptoms appearing on the lower foliage may be attributed to the fact that P is mobile within plant tissues and is translocated from these older leaves to the young developing tissues under periods of low P.
As symptoms progress, the leaves begin to develop sunken necrotic spots over the leaf surface (Fig 3.). The lower leaves that were previously mottled in appearance are evenly chlorotic with necrotic spotting. These necrotic spots form first on the lower leaves and later on the younger foliage. With these intermediate symptoms, the upper foliage has a generally olive green appearance.
In advanced cases, the plant remains severely stunted, with the oldest leaves becoming entirely necrotic. The chlorosis and necrotic spotting works its way up the foliage with only the youngest leaves remaining green. This wide range of symptoms may be observed in the 360-degree image below (Fig. 4, click image to play video).
We would like to express our appreciation to the North Carolina Tobacco Foundation for supporting this project. We will be providing updates as symptoms progress over the course of the nutrient disorder induction phase of the experiment.
Key Contact: Dr. Matthew Vann, Department of Crop and Soil Science firstname.lastname@example.org
Contributing Authors: Josh Henry, Paul Cockson, Matthew Vann, and Brian Whipker
Funding Source: North Carolina Tobacco Foundation
Project Team: Josh Henry (NC State M.S. student in Horticultural Science), Paul Cockson (NC State B.S. student in Agroecology), Ingram McCall (Research Technician in Horticultural Science), Rhonda Conlon (Extension IT at NC State), Matthew Vann (Tobacco Extension Specialist, Dept. of Crop and Soil Science), and Brian Whipker (Professor of Floriculture and Plant Nutrition in Horticultural Science).