Data on rhizosphere pH, phosphorus uptake and wheat growth responses upon TiO2 nanoparticles application

In this study, the data sets and analyses provided the information on the characterization of titanium dioxide nanoparticles (TiO2 NPs), and their impacts on rhizosphere pH, and soil-bound phosphorus (P) availability to plants together with relevant parameters. For this purpose, wheat (Triticum aestivum L.) was cultivated in the TiO2 NPs amended soil over a period of 60 days. After harvesting, the soil and plants were analyzed to examine the rhizosphere pH, P availability in rhizosphere soil, uptake in roots and shoots, biomass produced, chlorophyll content and translocation to different plant parts monitored by SEM and EDX techniques in response to different dosages of TiO2 NPs. The strong relationship can be found among TiO2 NPs application, P availability, and plant growth.


a b s t r a c t
In this study, the data sets and analyses provided the information on the characterization of titanium dioxide nanoparticles (TiO 2 NPs), and their impacts on rhizosphere pH, and soil-bound phosphorus (P) availability to plants together with relevant parameters. For this purpose, wheat (Triticum aestivum L.) was cultivated in the TiO 2 NPs amended soil over a period of 60 days. After harvesting, the soil and plants were analyzed to examine the rhizosphere pH, P availability in rhizosphere soil, uptake in roots and shoots, biomass produced, chlorophyll content and translocation to different plant parts monitored by SEM and EDX techniques in response to different dosages of TiO

Value of the data
The data provides information of TiO 2 NPs effects on wheat over a period of 60 days for better understanding of their long-term impacts on plant growth.
The data can help to understand the relationship between TiO 2 NPs application and phytoavailability of P for farm and field level applications to ensure nutrient management.
The data suggested the scientific community to extend the exposure time and comparison with other plant species instead of very short term bioassays.
Future experiments can be compared with this data to predict the optimum concentrations of NPs for better plant development for different plant species.

Data
The datasets and analyses described the impacts of soil applied titanium dioxide nanoparticles (TiO 2 NPs) on wheat (Triticum aestivum L.) plants. Corresponding figures, graphs, and images are provided with this article.

Synthesis and characterization of TiO 2 NPs
TiO 2 general purpose reagent was obtained from Sigma Aldrich Inc. (purity 4 99%, St. Louis, MO, USA) and further processed, and calcined at 500°C to synthesize pure anatase crystal structure of TiO 2 NPs as described in Zahra et al. [1]. Scanning electron microscope (SEM, Jeol, JSM 6490A, Tokyo, Japan), energy-dispersive X-ray spectroscopy (EDX, Jeol, JED 2300), and X-ray diffraction (XRD) analyses of as-prepared TiO 2 NPs were performed as shown in    days following randomized block design where the position of the pots was altered to avoid environmental bias effects.

Analysis of soil and plants
After 60 days of TiO 2 NPs exposure, the plants were uprooted and shaken carefully to remove soil at harvesting. The loosely bound soil adhered to the roots was collected with gentle washing in distilled water (100 mL) to investigate the rhizosphere pH (Fig. 2) and P (Fig. 3) using Olsen's method [2]. The roots and shoots were cut and dried in hot air oven for 48 h at 70°C. After that, the dry biomass was recorded (Table 1) and stored for P analysis. For plant P content analysis, 100 mg of ground plant samples were added to acid mixture containing 5 mL of HNO 3 /HClO 4 (2:1). This was digested on a hot plate followed by filtration through Whatman filter paper no. 42 to get clear aliquots for P content analysis ( Table 2) using the vanado-molybdo-phosphoric acid colorimetric method [3].

Estimation of leaf chlorophyll content
A hand-held chlorophyll meter was used to measure the chlorophyll content index (CCI). The CCI readings were taken after the 30th day of NPs exposure for 16 alternate days until harvest. The everyday measurements are the mean of 32-48 readings for each treatment (Fig. 4). Following

Table 1
Effect of TiO 2 NPs treatments on plant shoot and root dry biomass of wheat. calibration Eq. (1) was used to process the raw data and convert the CCI index values to chlorophyll content expressed as m cm −2 [4].
where y ¼ Total chlorophyll content x ¼ Chlorophyllmetervalue

Microscopic analysis of plant
To investigate the uptake of TiO 2 NPs, plant samples were observed under SEM equipped with EDX to demonstrate the elemental composition of the control (0 mg kg −1 TiO 2 NPs) and treated (60 mg kg −1 TiO 2 NPs) samples of roots (Fig. 5), and shoots (Fig. 6).

Statistical analysis
The statistical significance analysis was done using Student's T-Test available in the Microsoft Excel analysis tool box. One-way ANOVA test was performed to identify statistically significant differences between the treatments. Statistix 8.1 was used to identify the least significant differences (LSD) at p o 0.05. All the data presented here supports the findings and discussion in Rafique et al. [5]. Data is the mean of four replicates 7 Standard Deviation (SD). Means followed by different letters in the same column indicate significantly significant results at p o 0.05.

Transparency document. Supporting information
Supplementary data associated with this article can be found in the online version at http://dx.doi. org/10.1016/j.dib.2018.02.002.