Changes in growth, photosynthetic activities, biochemical parameters and amino acid profile of Thompson Seedless grapes (Vitis vinifera L.).

The study on photosynthetic activity and biochemical parameters in Thompson Seedless grapes grafted on Dog Ridge rootstock and its impact on growth, yield and amino acid profile at various stages of berry development was conducted during the year 2012-2013. Leaf and berry samples from ten year old vines of Thompson Seedless were collected at different growth and berry developmental stages. The analysis showed difference in photosynthetic activity, biochemical parameters and amino acid status with the changes in berry development stage. Higher photosynthetic rate of 17.39 umol cm(-2) s(-1) was recorded during 3-4mm berry size and the lowest (10.08 umol cm(-2) s(-1)) was recorded during the veraison stage. The photosynthetic activity showed gradual decrease with the onset of harvest while the different biochemical parameters showed increase and decrease from one stage to another in both berry and leaves. Changes in photosynthetic activity and biochemical parameters thereby affected the growth, yield and amino acid content of the berry. Positive correlation of leaf area and photosynthetic rate was recorded during the period of study. Reducing sugar (352.25 mg g(-1)) and total carbohydrate (132.52 mg g(-1)) was more in berries as compared to leaf. Amino acid profile showed variations in different stages of berry development. Marked variations in photosynthetic as well as biochemical and amino acid content at various berry development stages was recorded and thereby its cumulative effect on the development of fruit quality.

Free amino acid profiling in grain amaranth using LC-MS/MS.

Reliable and reproducible techniques for identification and quantification of amino acids usually require derivatization. However, techniques such as LC-MS/MS may perhaps sideline the derivatization with significant accuracy. Understanding the interaction between free amino acids and several physiological processes apparently requires that the pool be studied in the seed itself. Data on free amino acid content of grain amaranth is very inadequate. The present analysis revealed a higher concentration of essential amino acids especially Threonine and Tryptophan than non essential amino acids. The study constitutes first report of use of LC-MS/MS method for analysing the free amino acid composition of amaranth grain.