Disentanglement of the secrets of aluminium in acidophilic tea plant (Camellia sinensis L.) influenced by organic and inorganic amendments.

Field experiment was carried out for four years in mature tea (Camellia sinensis L.) growing plot to investigate the impacts of different doses of inorganic and organic fertilizers on aluminium (Al) distribution pattern in soil and different parts of tea plant, leaf pigment concentration, gas exchange parameters, as well as the yield of tea. Results indicated that application of 6 × 103 kg compost ha-1 significantly increased the dry matter yields of tea. Pluckable shoot of tea plant were markedly stimulated in the presence of Al irrespective of treatment imposed. Furthermore, Al induced growth stimulation in tea plant was facilitated by higher photosynthesis rate as well as gas exchange parameters. For the present experiment, Tea Research Association Heavy Metal Contamination Index (TRAHMCI) decreases with increase the fertilizer dose and all the experimental soils were found non-polluted with respect to Al. Localization of Al in the root apex predominantly accumulated in the cortex. The translocation of Al from root to shoot was driven by the gradient in hydrostatic pressure and water potential. In all tea infusions influenced by different treatments, Al concentrations were within the maximum permissible limit of Al in drinking water by Provisional Tolerable Weekly Intake (PTWI) established by the Joint FAO/WHO Expert Committee on Food Additives (JECFA, 2 mg kg-1 bw-1) and the tolerable weekly intake (TWI) established by EFSA (European Food Safety Authority, 1 mg kg-1 bw-1). Application of stepwise multiple regression model indicates that around 75% of the variability in the yield of the crop can be expressed by the selected parameters under study. The Hierarchical cluster analysis reveals that two homogenous groups of treatment can be formed based on all the studied parameters.

Paradigm shift of contamination risk of six heavy metals in tea (Camellia sinensis L.) growing soil: A new approach influenced by inorganic and organic amendments.

The present study provides several contamination and ecological risk indices for selected metals (Cd, Cr, Cu, Mn, Ni and Zn) in tea (Camellia sinensis L.; cv. S.3A/3) growing soil influenced by lower to higher doses of inorganic and organic amendments. While ecological risk indices were applied, it was observed that same treatment showed different risk levels but contamination risk status did not vary significantly. All the indices showed significant correlation with heavy metals' concentration in young shoots of tea plants. As the indices characterized experimental soils with different extents of contamination, it would be important to standardize the indices with long term experiments followed by generation of new index. Therefore, we formulated a new contamination index named as Tea Research Association Heavy Metal Contamination Index (TRAHMCI) for tea growing soils. TRAHMCI is based on the probable change of metal status in soil with progress of growth of tea plant. This could be useful to negate discrepancies arised from use of various existing metal contamination indices in tea growing soils amended with different doses of fertilizers. TRAHMCI was formulated based on individual contamination factor using statistical technique and applied to the present dataset which provided a more holistic understanding of overall tea growing soil behavior. The limitation of the developed TRAHMCI index is that, the index had not been validated for other crops in our study not to claim its effective use for crops other than tea. As already mentioned, this new index had been formulated by taking tea as the test crop with above mentioned six heavy metal contents in young shoot and made tea.

Comparative Assessment of Copper, Iron, and Zinc Contents in Selected Indian (Assam) and South African (Thohoyandou) Tea (Camellia sinensis L.) Samples and Their Infusion: A Quest for Health Risks to Consumer.

The current study aims to assess the infusion pattern of three important micronutrients namely copper (Cu), iron (Fe), and zinc (Zn) contents from black tea samples produced in Assam (India) and Thohoyandou (South Africa). Average daily intakes and hazardous quotient were reported for these micronutrients. Total content for Cu, Fe, and Zn varied from 2.25 to 48.82 mg kg-1, 14.75 to 148.18 mg kg-1, and 28.48 to 106.68 mg kg-1, respectively. The average contents of each of the three micronutrients were higher in tea leaves samples collected from South Africa than those from India while the contents in tea infusions in Indian samples were higher than in South African tea samples. Results of this study revealed that the consumption of 600 mL tea infusion produced from 24 g of made tea per day may be beneficial to human in terms of these micronutrients content. Application of nonparametric tests revealed that most of the data sets do not satisfy the normality assumptions. Hence, the use of both parametric and nonparametric statistical analysis that subsequently revealed significant differences in elemental contents among Indian and South African tea.