Hello dear

I suggest to read my paper to help in interpretation the relation between chlorophyll content and abiotic stress tolerance DOI: 10.1186/s12870-016-0761-0. actually, you do not mention whether those lines with higher chlorophyll accumulation are stress tolerant. under stress conditions, plant can involve different pathways to sustain metabolism process. However, there are many factors could affect the chlorophyll measurement using SDAP such the heterogenous of chlorophyll content in different tissue, do you use the same position in tested plants. you can confirm the result by assay the chlorophyll content using 80% acetone method. also I suggest to measure the photosynthesis parameters becuase chlorophyll could reflect directly on its efficiency. 

I hope to be useful for you

Guess its simply differences in dry matter content!

Is the flowering early in plants under drought and heat stress?Have the plants put up less dry matter  under drought and heat stress?Crop plants try to complete life cycle  early under stress  conditions by keeping their moisture and nutritional requirements low.As suggested by Dr. Schnug there would be difference in dry matter production.

Dear Bacher, thank you for sharing your paper. Yes we measured the chlorophyll on specific leaf. The first leaf from spike. Would you think that chlorophyll increased under drought and heat because the flag leaf respires quickly and increases the photosynthes than under control. Then, the chlorophyll accumulates in this leaf in a higher mount under stress than control. 90% of genotypes showed an increase in chlorophyll content under stress except very few.    

Dear Ewald, could you please clarify your sentence in more detail, I would appreciate it. 

we observe an increase of the DM content under such stress situation caused by a reduction of mass production which relatively increases the concentration of minerals and biochemical compounds in a tissue.

Thank you so much for your answer. Could you please share me your study about this point? what is the title of this research if you published it? thanks again

Hello all

my respects to previous comments. I agree with prof. EWald in the increase of osmoprotectants under osmotic stress, but under adverse abiotic stress conditions, one should keep in mind the potential increase in  oxidative radicals such as NO and ROS that could degrade and cause damage to other cellular components. as we know chlorophyll localize in chloroplast where the production of ROS can be accelarated under drought stress leading to chorophyll degradation DOI: 10.1093/jxb/ert208.

according to your discription, I guess you want to identify the tolerant lines, therefore in my opinion it had better to support your observation by more parameters to make sense such as ROS content , photosynthetic efficiency, biomass, ratio N/C ....

best wishes

Thanks Bachar.. I will no bet able to measure these parameters.. but your paper is useful... As you said the main objective is to study the changes in chlorophyll under drought and heat at flowering and seedling and to identify the tolerant and susceptible genotypes

Respected sir, i measured chlorophyll content using SPAD meter in my research related to drought tolerance in pigeonpea. But the results are quite different in even in the same leaf. Its better to go through the acetone method before you conclude your results. I also opted for the second one. 

Thanks Naidu for answering. what were you results under control and drought???

I have a similar result but it is not due to differences in dry matter content. Dry weights are similar but chlorophyll content is very different under drought and I got similar results is several genotypes

Drought tolerance can mean many things and many plant processes can be affected by drought, which can also mean many things. So it is not possible to use one measure to describe a complex situation. The question is too simplified. I have dealt with the problem in different publications listed in Research Gate and suggest  reading  them and the literature given there.  Chlorophyll fluorescence is a valuable technique but only under particular conditions, such as rapid and relatively severe dehydration but may not be useful under mild drought which affects growth processes and yield without altering photosynthetic metabolism greatly and so does not alter chlorophyll fluorescence. Chlorophyll content /concentrations in leaves are not a useful indicator of early drought effects unless the water deficit is rapid and large. If a specific list of references is required I can supply later. 

Gregor Steve I think, Under drought condition, chlorophyll content of leaf is increasing due to inherent potential of plant that prevent denaturation of protein or formation of HSP (Heat Shocking Protein) in the plant. Level of chlorophyll content depends upon the treatments which have been taken in the study.