Abstract

At high concentrations, Aluminium (Al) can be a serious threat to agricultural production because it inhibits growth of the roots, inducing oxidative stress, callose induction, peroxidation of the cellular membrane, nutrient imbalances and ends with cell death. This finding aimed to investigate threshold toxicity level of Al on finger millet varieties. The threshold value was determined by wrapping and germinating twenty randomly selected and surface sterilized seeds in petri dishes. Thirty-six hours-old seedlings of uniform size in three replication were transferred to the nutrient solution having Al concentrations ranging from 0 to 200 µM and allowed to grow for a further 8 days. It was found that biomass production decreased in root starting from 50 µM. The finger millet plants growing displayed three distinct Al tolerance phases in roots. A high phase tolerance occurred between 0 and 50 µM, slight tolerance between 50 and 125 µM and intolerance phase above 125 µM. The conclusion was that under the defined growth conditions, Al toxicity would likely begin with an Al concentration in the solution higher than 50 µM.

Key words: Aluminium tolerance, finger millet, hydroponics, threshold, variety.

Abbreviation

ANOVA: Analysis of Variance; FW: Fresh Weight; RGI:  Root Growth Inhibition; RL: Root Length; RTRL:      Relative Total Root Length; SL: Shoot Length.