High relative air humidity influences mineral accumulation and growth in iron deficient soybean plants.

Mariana Roriz,Susana M. P. Carvalho,Marta W. Vasconcelos

doi:10.3389/fpls.2014.00726

Mariana Roriz, Susana M. P. Carvalho + Show 1 more

Open Access

https://doi.org/10.3389/fpls.2014.00726

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Abstract

Iron (Fe) deficiency chlorosis (IDC) in soybean results in severe yield losses. Cultivar selection is the most commonly used strategy to avoid IDC but there is a clear interaction between genotype and the environment; therefore, the search for quick and reliable tools to control this nutrient deficiency is essential. Several studies showed that relative humidity (RH) may influence the long distance transport of mineral elements and the nutrient status of plants. Thus, we decided to analyze the response of an “Fe-efficient” (EF) and an “Fe-inefficient” (INF) soybean accession grown under Fe-sufficient and deficient conditions under low (60%) and high (90%) RH, evaluating morphological, and physiological parameters. Furthermore, the mineral content of different plant organs was analyzed. Our results showed beneficial effects of high RH in alleviating IDC symptoms as seen by increased SPAD values, higher plant dry weight (DW), increased plant height, root length, and leaf area. This positive effect of RH in reducing IDC symptoms was more pronounced in the EF accession. Also, Fe content in the different plant organs of the EF accession grown under deficient conditions increased with RH. The lower partitioning of Fe to roots and stems of the EF accessions relative to dry matter also supported our hypothesis, suggesting a greater capacity of this accession in Fe translocation to the aerial parts under Fe deficient conditions, when grown under high RH.

Highlights

Humans and plants need essential micronutrients for the proper functioning of cellular processes (O’Rourke et al, 2009)
CHARACTERIZATION OF MORPHOLOGICAL AND PHYSIOLOGICAL PARAMETERS The impact of Fe deficiency was more pronounced in plants of the EF accession grown at 60% relative humidity (RH) which developed the typical Iron deficiency chlorosis (IDC) symptoms: stunted growth and a decreasing chlorophyll concentration trend (SPAD values 32% lower) relative to plants grown under high RH (Figures 1, 2)
In the EF plants grown under Fe deficient conditions, we found that the increase in RH resulted in significantly increased plant height (25%), root length (33%), plant dry weight (DW) (42%), and leaf area (39%) but it had no significant effect on the root:shoot ratio (Table 1)

Summary

Introduction

Humans and plants need essential micronutrients for the proper functioning of cellular processes (O’Rourke et al, 2009). Iron deficiency chlorosis (IDC) is a common symptom caused by lack of available Fe, occurring worldwide. It is characterized by a significant decrease in chlorophyll leaf content (Vasconcelos and Grusak, 2014), reduced leaf area and total plant dry weight (DW) (Zaharieva et al, 2004; Rabhi et al, 2007; Zocchi et al, 2007), resulting in diminished yield and crop quality (Vasconcelos and Grusak, 2014). The Fe concentration in seeds and other plant organs is reduced in plants affected by IDC (Grusak, 1999). There are different susceptibilities to Fe deficiency between cultivars of the same species, and environmental conditions and genetically determined factors affect cultivar

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