In a benedict's test..?

Question

Just the change of colour from light blue to greenish blue should mean positive result for Benedict's test or is the red precipitate necessary for the test to be positive?

Because, when I performed Benedict's test on various developmental stages of barley seeds, I didn't get the red precipitate for the germinating barley seeds and dormant barley seeds (I only got it for whole barley seedlings). I did get the change of colour from light blue to greenish blue for germinating, dormant and whole seedlings (only whole seedlings plus the red precipitate).

Thank you! I appreciate your help.

Answer 1

With Benedict's test the colour you get is related to the amount of reducing sugar present - a greenish blue is a positive result but indicates a relatively low amount - as the colour gets more intense then a red colour will be obtained.  What your results indicate is that reducing sugars are present at all stages you tested with the most being present in whole seedlings.

Answer 2

benedict test is to detect amt of reducin sugar. in dormant seed there is no accumulated sugar so no colour but gradually on germination due to photosynthesis seed acccumulate the sugar which is seen in positive test