The effect of pH on boron toxicity and nutrient uptake by wheat and rapeseed

Abstract

Although boron (B) is essential micronutrient, higher soil B concentrations become toxic to the plants in arid and semi-arid regions of the world. Very little is known about the pH related nutrient solubility, including transpiration-mediated B uptake by plants. The effects of high B (200 μM) and low to high pH (3.0–10.0) on B toxicity, transpiration and nutrient uptake by wheat and rapeseed were studied. Plants were grown for 5 weeks under greenhouse conditions and analyzed for elements concentrations. Regardless of high B or not, low pH favored in the higher B accumulation in roots and shoots of both plant species. However, both plant species exhibited a differential B uptake pattern in roots and shoots. Both low and high pH levels in combination with high B decreased the plant biomass, transpiration, N and Mg concentrations, whereas increased the K, Ca, S, Cu, Fe, Mn and Zn concentrations. With the increase in pH 3.0–10.0, excess B decreased the Cl concentrations in wheat and rapeseed. In conclusion, low pH and high B supply enhanced the transpiration-assisted B uptake by plants although pH alone had little effects on B concentrations. Furthermore, nutritional disorder caused by high B in conjunction with low to high pH (3.0–10.0) inhibited the plant growth and transpiration.

Keywords:

• High B
• nutrient uptake
• pH
• rapeseed
• transpiration
• wheat

Acknowledgements

We thank Chinese Academy of Sciences for funding postdoctoral fellowship to the first author under the program of President’s International Fellowship Initiative (No. 2015PB054).

Author contributions

Sajid Masood: Research conceptualization, experimentation, formal analysis and methods exploration, initial draft preparation, interpretation of the data. Xue Qiang Zhao: Research conceptualization, review and editing of the draft, funding acquisition. Ren Fang Shen: Supervision, funding acquisition. SM designed and performed the study. In addition, SM devised the manuscript. XQZ and RFS helped in experimental design and revising the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Data availability statement

All the data are available on reasonable request to corresponding author.