Standardization of technique for the wet preservation of diseased plant specimens

Experiments were conducted during 2019-20 and 2020-21 to standardize technique of wet preservation for plant specimens without losing actual disease symptoms of the plant tissues. Succulent leaf and hardy samples in triplicate for each disease were dipped in 4-5 per cent copper sulphate (CuSO₄) solution for 4-6 hours. Finally, the samples were stored in formalin and different concentration of sulfurous acid (H₂SO₃), sterilized distilled water and tap water. Observations were recorded at monthly interval on percent bleaching and visibility of disease symptom. The succulent samples of diseased leaves stored in 0.5 per cent H₂SO₃ solution and sterilized distilled water exhibited minimum bleaching (33.33% and 16.67% respectively) with highest visibility of disease symptoms amounting of 56.67 and 36.67 per cent respectively after 6 months. However, 1.0 per cent concentration of H₂SO₃ solution was found most effective to preserve the hardy diseased leaves and stem samples which cause least bleaching (6.67%) and exhibited highest visibility of actual disease symptom (83.33%) up to 6 months.