The different ratio of chlorophyll "a" to chlorophyll "b" is a plant feature and depends on which family the species belongs to.

Best regards!

I agree with you. 

Dear Ibrahim, the chl a/b ratio could be an indicator of excess energy. Please see: Ogbaga, C.C., Stepien, P., Johnson, G.N., 2014. Sorghum (Sorghum bicolor) varieties adopt strongly contrasting strategies in response to drought. Physiol. Plant. doi:10.1111/ppl.12196

Dear Ibrahim:

The ratio betwen chl a and b it depend of grade of radiation that the plant receive, plants in the shadows could have a ratio below 1 and in the sun this ratio increase.

Interesting discussion..

 Cholophyll b traps the light energy and pass on to chlorophyll a.  Chlorophyll b’s main function is to collect energy from the blue spectra but an important secondary function is to regulate the light harvesting antenna size. Chlorophyll beta is found only in peripheral light-harvesting complexes (LHCs) and in nearly equal amounts between Chl a and Chl b. Then chlorophyll a also occupies the reaction center of the antenna array and  is required for assembly of these complexes around it...

In some literature, I have found that age of the leaves have also a significant impact on ratio of Chl a and b. I also would like to know, is it true??

Yes..it could be possible..

under severe stress conditions or during senescences processes it may be occurred. but in normal, chloorophyll b didnot exceed over chlorophyll a

Yes it happened only in leaves at ripening stage of fruit.

Yes i also found higher Chl b content than chl a while i  examine in paddy plants under stress environments.

Usually chlorophyll b is observed higher than chlorophyll a under certain stressed conditions only..

In Citrus root stocks grown in lathhouse i found that chlorophyll a content exceeded chlorophyll b even when plants irrigated with saline water .