Individual versus Combinatorial Effects of Silicon, Phosphate, and Iron Deficiency on the Growth of Lowland and Upland Rice Varieties

Abstract

Mineral nutrient homeostasis is essential for plant growth and development. Recent research has demonstrated that the occurrence of interactions among the mechanisms regulating the homeostasis of different nutrients in plants is a general rule rather than an exception. Therefore, it is important to understand how plants regulate the homeostasis of these elements and how multiple mineral nutrient signals are wired to influence plant growth. Silicon (Si) is not directly involved in plant metabolism but it is an essential element for a high and sustainable production of crops, especially rice, because of its high content in the total shoot dry weight. Although some mechanisms underlying the role of Si in plants responses to both abiotic and biotic stresses have been proposed, the involvement of Si in regulating plant growth in conditions where the availability of essential macro- and micronutrients changes remains poorly investigated. In this study, the existence of an interaction between Si, phosphate (Pi), and iron (Fe) availability was examined in lowland (Suphanburi 1, SPR1) and upland (Kum Hom Chiang Mai University, KH CMU) rice varieties. The effect of Si and/or Fe deficiency on plant growth, Pi accumulation, Pi transporter expression (OsPHO1;2), and Pi root-to-shoot translocation in these two rice varieties grown under individual or combinatorial nutrient stress conditions were determined. The phenotypic, physiological, and molecular data of this study revealed an interesting tripartite Pi-Fe-Si homeostasis interaction that influences plant growth in contrasting manners in the two rice varieties. These results not only reveal the involvement of Si in modulating rice growth through an interaction with essential micro- and macronutrients, but, more importantly, they opens new research avenues to uncover the molecular basis of Pi-Fe-Si signaling crosstalk in plants.

Silicon Compensates Phosphorus Deficit-Induced Growth Inhibition by Improving Photosynthetic Capacity, Antioxidant Potential, and Nutrient Homeostasis in Tomato

“…While deficit P supply decreased concentrations of different essential elements, such as K, Na, Ca, Mg, Fe, Mn, and Zn (Table 4), exogenous Si supply increased their concentration under low P conditions with a few exceptions. Among essential micronutrients, Fe is a key component of numerous proteins and enzymes and its deficiency impairs a number of metabolic processes in plants [19,20]. In cucumber, exogenous Si application alleviates Fe deficiency by regulating the expression of genes involved in Fe acquisition [20].…”

“…Despite a large number of reports on the role of exogenous Si in relieving oxidative stress under abiotic stresses, such as drought, salinity, and high temperature, few reports have described the potential association between Si-induced amelioration of oxidative stress and improvement of macronutrient utilization efficiency [19]. In the present study, we showed that exogenous Si application not only alleviated LP-induced oxidative stress but also increased acquisition of most essential nutrients ( Figure 6), leading to potential improvement in nutrient utilization efficiency under low P supply.…”

“…For example, seed priming with Si alleviates arsenic (As) stress in rice by improving antioxidant capacity and osmoregulatory substances (proline), which greatly reduced oxidative stress [16]. Not only As but also Si have been shown to increase plant growth in soils that are contaminated with multiple heavy metals, such as Cd, Zn, Cu, and Pb, wherein stimulation of enzymatic and nonenzymatic antioxidants and sequestration of metals into vacuoles and cell walls might function as important internal mechanisms [11].Recently, the role of Si in mitigating nutrient imbalance has received great attention due to rising deficiency of essential elements in soils worldwide [19]. Studies revealed that Si plays a dual role in deficiency and abundance (toxicity) of an essential element.…”

“…Recently, the role of Si in mitigating nutrient imbalance has received great attention due to rising deficiency of essential elements in soils worldwide [19]. Studies revealed that Si plays a dual role in deficiency and abundance (toxicity) of an essential element.…”

Can Aluminum Tolerant Wheat Cultivar Perform Better under Phosphate Deficient Conditions?

“…It has been reported that Pi deficiency leads to an increase of Fe content and alterations of other mineral elements [ 44 , 45 , 46 , 47 ]. In agreement with these reports, the contents of Fe were shown increased under Pi deficiency in the roots of both cultivars, particularly in the Scout 66, in which more than two fold-changes of Fe content were determined between Pi deficiency and Pi sufficiency.…”