Effects of the Interactions Between Selenium and Phosphorus on the Growth and Selenium Accumulation in Rice (Oryza Sativa)

Abstract

The solution culture, paddy soil culture and the simulation experiments in the laboratory were conducted to clarify the interactions between selenium and phosphorus, and its effects on the growth and selenium accumulation in rice. Results revealed that a suitable supply of selenium could promote rice growth and excessive selenium could injure rice plant, causing lower biomass, especially in the roots. The supply of selenite could enhance the selenium contents of rice shoots and roots in solution culture and in soil culture. The selenium concentrations in roots were much higher than those in shoots supplied with the same rates of selenium and phosphorus. The interaction between selenium and phosphorus was evident. When the phosphorus supply increased to meet the needs of plant growth, phosphorus could promote absorption and accumulation of selenium in the shoots. If the phosphorus supply was excessive, phosphorus could inhibit the accumulation of selenium in the shoots at the lower selenite level (2 micromol l(-1)), but could not at the higher selenite level (10 micromol l(-1)). With the supply of phosphate increased, the selenium concentrations in the roots decreased significantly at both selenite levels. The presence of phosphate could decrease Se sorption on the soil surface and increase the selenium concentration in the soil solution. The concentrations of selenium in shoots and roots supplied with 0.08 g kg(-1) phosphorus were lower than those with no phosphorus supplied. With the increase of phosphorus added to 0.4 g kg(-1), the selenium concentration in shoots and roots increased. The effect of phosphorus on the concentration was statistically significant at all three selenium levels.

Effects of selenium on the growth and photosynthetic characteristics of flue-cured tobacco (Nicotiana tabacum L.)

“…Similarly, other studies revealed that Se promotes the growth of ryegrass [3], tea [9], rice [10], and soybean [11]. However, excess Se accumulation (>0.1% plant DW) is generally toxic to plants, except for rare Se-hyperaccumulating plants [4].…”

Effect of phosphate and sulfate fertilizers on selenium uptake by wheat (Triticum aestivum)

“…However, Mora et al (2008) showed that there was no effect of fertilizer P addition on Se uptake in white clover (Trifolium repens L.) in non-limed soil. Some other studies showed that P can reduce the uptake and accumulation of Se in plants (Liu et al 2004;Mora et al 2008). The interaction between S and Se uptake and accumulation in plants has been shown in positive and negative correlation (Cruz-Jimenez et al 2005;Cartes et al 2006;Huang et al 2008;Mackowiak and Amacher 2008;McGregor et al 2008;Stroud et al 2010).…”

“…This result conflicted with several other studies which found that the addition of P fertilizer increased Se concentration in plant tissue. For example, Liu et al (2004) found that P addition increased absorption and accumulation of Se in rice (Oryza sativa) shoots when the P supply increased. Selenium concentration in alfalfa grown in alkaline and acid conditions also increased after P fertilizer applications (Carter et al 1972).…”

Selenium speciation and bioavailability in Dutch agricultural soils: the role of soil organic matter

“…sulphate and phosphate, and organic anions, such as oxalate and citrate, influences bioavailability of Se via competition for adsorption on soil mineral surfaces and General introduction plant uptake. It has been found that addition of phosphate into soils increases Se plant uptake, due to an increase of competition between phosphate and Se (mainly selenite) for the adsorption on soil mineral surfaces, releasing the adsorbed Se into soil solution becoming available for plant uptake (Carter et al, 1972;Liu et al, 2004;Eich-Greatorex et al, 2010). Sulphate competes stronger with selenate than with selenite for plant uptake, and the competition between sulphate and selenate is stronger than that between phosphate and selenite (Hopper and Parker, 1999;Cartes et al, 2006).…”

“…shown that there is an increase of Se uptake in plants upon phosphate fertilization (Carter et al, 1972;Liu et al, 2004), which can be either due to a competition effect between phosphate and Se (mainly selenite) for the adsorption on soil mineral surfaces, releasing the adsorbed Se into soil solution (Carter et al, 1972;Liu et al, 2004;Eich-Greatorex et al, 2010) or due to the increase of root proliferation, resulting in more root-soil contact to take up Se (Carter et al, 1972). On the other hand, Se uptake by plants can be increased or decreased upon sulphate fertilization (Cartes et al, 2006;Stroud et al, 2010b), depending on the plant S status (i.e.…”