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United States Department of Agriculture

Agricultural Research Service

Research Project: Physiological Characterization of Salt Tolerant Alfalfa Germplasm

Location: Forage and Range Research

2011 Annual Report


1a.Objectives (from AD-416)
Characterize the physiological mechanism(s) of salinity tolerance in selected alfalfa lines by identifying how the plants cope with saline soils.


1b.Approach (from AD-416)
Three major salinity tolerance mechanisms in plants have been identified; salt secretion, exclusion and sequestration. It is hypothesized that salt-tolerant alfalfa may utilize one or more of these mechanisms. Detailed physiological analysis will be conducted to determine which mechanism(s) confer salinity tolerance to experimental lines of alfalfa. Alfalfas with contrasting salinity tolerance will be analyzed for salt gland formation, deposit of salt crystal on tissue surface, salt contents in different tissues and distribution of salt at the cellular and sub-cellular level. In addition, assays for oxidative stress and detoxification will also be performed.


3.Progress Report

The main objective of this project is to determine the physiological mechanisms of salt tolerant alfalfa germplasm. Four populations of alfalfas selected for salt tolerance in the greenhouse are the subject of this research. In anticipation of conducting the work field trials were established in the spring of FY 2009 near Castle Dale, Utah under saline conditions and near Milville, Utah under non-saline conditions. The first year morphological data was used to select plants for additional physiological and molecular characterization.

During FY-2011: The selected genotypes were cloned in the field and subjected to replicated salinity treatments in the greenhouse, in Logan, UT. Salt and control treated plants were monitored for physiological performance by measuring, stem elongation, branch number, leaf size and number, chlorophyll, Relative Water Content, organic solute, and electrolyte leakage over a 4 week treatment period. Measurements were taken by a Graduate Student recruited to the project at SDSU. Training on physiological techniques in alfalfa was conducted at SDSU prior to the students visit to Logan. Statistical analysis of the physiological data was completed at SDSU.

Monitoring Methods: • Email correspondents with SDSU collaborator. • Conference calls with SDSU Plant Physiologist to discuss research goals, techniques, and graduate student research objectives. • Graduate student from SDSU visited Logan to conduct 4 weeks of physiological measurements. • Periodic project status meetings


Last Modified: 8/27/2014
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