Abstract
Root system architecture depends on nutrient availability. A symptom of iron (Fe) toxicity in plants is stunted root growth, yet little is known about the effects of excess Fe on lateral root (LR) development. To better understand how nutrient signals are integrated into root developmental programs, we investigated the morphological response of Arabidopsis thaliana root systems to Fe by testing homogeneous supply and localized Fe supply treatment.
Keywords: Arabidopsis, Fe toxicity, Lateral root, Localized iron supply, Homogeneous iron supply
Background
A localized supply of nutrients regulates lateral root elongation and/or lateral root density in Arabidopsis thaliana. Lateral root formation is affected by nutrients at different developmental stages (e.g., initiation versus elongation) and in a nutrient-specific manner (Li et al., 2011; Giehl et al., 2012). Iron toxicity as a syndrome in plants is typically associated with an excessive amount of the ferrous form (the Fe2+ ion) in the soil (Vigani, 2012). Iron toxicity symptoms vary with cultivars and are characterized by a reddish-brown, purple bronzing, yellow, or orange discoloration of the lower leaves and a stunted root growth. The presence of the Fe2+ ion is increased by low pH and anoxic conditions, and there is an increasing presence in vertically lower strata (Becker and Asch, 2005; Li et al., 2016). We describe a detailed pipeline used for localized iron supply in Arabidopsis grown in vitro which we validated in Arabidopsis (Li et al., 2015a; 2015b and 2016).
Materials and Reagents
Equipment
Procedure
Data analysis
After treatment count the number of lateral root initiation events under a dissecting microscope. The developmental stage of each lateral root primordia (LRP) is classified according to Zhang et al. (1999) into the following stages: stage A, up to three cell layers; stage B, unemerged, more than three cell layers; stage C, emerged LRs, less than 0.5 mm in length; and stage D, LRs, greater than 0.5 mm. The emerged but not activated LRP are still referred to as LRP, and only mature LRs (exceeding 0.5 mm in length) are denoted as LRs (Figure 4C). The number of lateral root initiation events is stage A + B + C + D (Figure 4D).
Notes
Recipes
Acknowledgments
This work was supported by the National Natural Science Foundation of China (31430095) and the Chinese Academy of Sciences Innovation Program (CAS ISSASIP1604). This protocol was adapted from Li et al., 2015a.
References
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