Effects of solution pH on the growth and chemical composition of rice plants

Alam, S. M.

doi:10.1080/01904168109362916

Cited by 29 publications

(11 citation statements)

References 36 publications

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“…The results of the present study agree with the results of other studies (Rahman et al 2009;Chun et al 1997). Alam (1981) also reported substantial reduction in rice plant biomass at pH 8.5. It is likely that the decrease in growth is the result of reduced Fe solubility, bioavailability and uptake due to the formation of Fe-oxide/hydroxide precipitates in the growing medium at high pHs under aerobic conditions (Alam 1981;Rahman et al 2009).…”

Section: Ph and Mgda Concentration Influencesupporting

confidence: 93%

“…Alam (1981) also reported substantial reduction in rice plant biomass at pH 8.5. It is likely that the decrease in growth is the result of reduced Fe solubility, bioavailability and uptake due to the formation of Fe-oxide/hydroxide precipitates in the growing medium at high pHs under aerobic conditions (Alam 1981;Rahman et al 2009). In most soils, Fe 3þ -oxides are a common source of Fe for plants, which after transformation in the rhizosphere is absorbed by plant in ionic and chelated forms via soil solution (Stein et al 2009).…”

Section: Ph and Mgda Concentration Influencementioning

confidence: 86%

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The significance of biodegradable methylglycinediacetic acid (MGDA) for iron and arsenic bioavailability and uptake in rice plant

Rahman

Maki

et al. 2012

Soil Science and Plant Nutrition

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Methylglycinediacetic acid (MGDA) is a readily biodegradable complexing agent in compliance with Organization for Economic Cooperation and Development standards. In the present study, the use of MGDA for iron (Fe) and arsenic (As) bioavailability and uptake by rice plants (Oryza sativa L.) was investigated. The highest plant biomass was observed at pH 7, and the growth of rice seedlings decreased significantly (p < 0.05) with increasing pH of the nutrient solution. This might be due to Fe deficiency to the plant at alkaline pH. When rice seedlings were grown with different concentrations of MGDA (0.1, 0.25, 0.5, 1.0, 2.5, and 5 mM), the highest plant biomass was observed at 0.25 mM MGDA, while further increases of the ligand concentration decreased the plant growth. Fe concentrations on rice root surfaces decreased gradually with increasing MGDA concentrations in the growing medium, while Fe concentrations in rice roots and shoots increased with increasing MGDA concentrations up to 0.25 mM and then decreased gradually. This indicates that the concentration of the chelating ligand influences Fe uptake in the plant. Arsenic concentrations on rice root surfaces decreased, while As concentrations in roots and shoots increased with the addition of MGDA in the growing medium, indicating that the ligand enhanced As bioavailability and uptake in rice. The mechanism behind the MGDA effect on Fe and As uptake in plant is likely to be due to that Fe exists mostly in insoluble particulate forms [e.g., ferric oxide (Fe 2 O 3), ferric hydroxide (Fe(OH) 3) and ferric oxyhydroxide (FeOOH)] at neutral or alkaline pH, and the soluble [e.g., ferric ion (Fe 3þ), iron hydroxide ion (Fe(OH) 2þ) and iron dihydroxide ion (Fe OH ð Þ þ 2)] and apparently soluble (colloidal) fractions of Fe are increased at moderate concentrations of the ligand that increases Fe bioavailability. Since arsenate [As(V)] binds to the insoluble Fe-oxides/hydroxides, the binding sites for As(V) decreases with the increase of the soluble fractions of Fe by the ligand, which slightly increased As uptake in rice plants.

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Section: Ph and Mgda Concentration Influencesupporting

confidence: 93%

Section: Ph and Mgda Concentration Influencementioning

confidence: 86%

The significance of biodegradable methylglycinediacetic acid (MGDA) for iron and arsenic bioavailability and uptake in rice plant

Rahman

Maki

et al. 2012

Soil Science and Plant Nutrition

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“…Ideal pH in hydroponic systems ranges from 5.5 to 6.0, but aquaponic solution pH is managed between 7.0 and 7.5 in an effort to balance the physiological demands of fish, plants, and nitrifying bacteria (Tyson et al, 2004). Differences in solution pH will alter plant nutrient uptake; specifically, uptake of iron and other metals will be reduced at higher pH levels commonly observed in aquaponic solution (Alam, 1981).…”

Section: Solution Chemistry and Nutrient Removalmentioning

confidence: 99%

“…Bacterial transformation of ammonia to nitrite and further to nitrate is optimized at pH 8.5, but plant nutrient uptake for many crop species is optimized near pH 6.0; thus, pH in aquaponic systems is managed near pH 7.0 to ensure sufficient rates of nitrification without jeopardizing plant uptake potential of essential nutrients in solution (Tyson et al, 2004). Higher pH values in aquaponic solution may limit the uptake efficiency of certain essential elements, like iron, which is already limited in aquaponic solution (Alam, 1981;Rakocy et al, 2006). Additional key differences exist between the chemistry of aquaponic and hydroponic solutions (e.g., dissolved organic matter and organic metabolites in aquaponic solution; Rakocy et al, 2006), but nutrient strength (EC) and pH seem to have the strongest potential for influencing physiology and yield of plants.…”

Section: Introductionmentioning

confidence: 97%

Crop physiological response to nutrient solution electrical conductivity and pH in an ebb-and-flow hydroponic system

Wortman

2015

Scientia Horticulturae

122

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“…Wheat and barley are reported to suffer a reduction in growth at pH 8.5 and 9.0 respectively (Hewitt, 1966).The effects of high salinity of the solution culture on different growth and gas exchange parameters have also been reported by different workers (Richards, 1969;Iqbal, 1992). Alam (1981) studied the effects of different pH levels in solution culture on rice growth and reported that growth was affected adversely at high pH. Optimal dry matter accumulation was noted at pH levels between 5.5 and 6.5, and maximum reduction in growth occurred at both pH 3.5 and 8.5.…”

Section: Introductionmentioning

confidence: 99%

Effects of Salinity and pH on Gas Exchange and Growth of Wheat under Hydroponic Conditions

Ahmad¹

2000

Pakistan J. of Biological Sciences

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The experiment was conducted on SARC-1 wheat in plastic pots in solution culture. Two salt-stress levels (0 mol mG 3 NaCl (control) and 100 mol mG 3 NaCl), and two pH levels (pH 5.8 and 8.5) were tested. Salt stresses were created by adding calculated amounts of commercial NaCl to the nutrient solution. pH 8.5 was created by adding 1.0 M KOH. Data provide some evidence that the effects of salinity on net photosynthesis (Pn) and growth were greater at high pH than at low pH. Percentage decreases in root, shoot weight and leaf area due to salinity were greater at high pH than at low pH. pH 8.5 in combination with 100 mol mG 3 NaCl proved very harmful for gas exchange and plant growth.

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Effects of solution pH on the growth and chemical composition of rice plants

Cited by 29 publications

References 36 publications

The significance of biodegradable methylglycinediacetic acid (MGDA) for iron and arsenic bioavailability and uptake in rice plant

The significance of biodegradable methylglycinediacetic acid (MGDA) for iron and arsenic bioavailability and uptake in rice plant

Crop physiological response to nutrient solution electrical conductivity and pH in an ebb-and-flow hydroponic system

Effects of Salinity and pH on Gas Exchange and Growth of Wheat under Hydroponic Conditions

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