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

Abstract

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.