the effect of folic acid on seed reserve partitioning and early vigor of wheat seedlings

in order to study the effect of folic acid on seed reserves partitioning and early vigor of seedlings of kavir wheat cultivar, an experiment was conducted in a completely randomized design with 0, 12.5, 25, 50, 100 and 200 mm of folic acid. results of this study indicated that dry weight of seeds decreased in a same pattern in all treatments and about 6-8% of total seed was structural section. variation in the seedling dry weight in control and folic acid treatments was similar but decreasing of seedling dry weight in control and folic acid treatments continued 10.46 and 7.93-8.53 days after soaking, respectively. then, dry weight of seedlings were increased because of reaching to autotrophic stage. it is worth mentioning that acid folic could shorten the time required to reach the onset of autotrophic stage (beginning of seedling dry weight increase) and the complete autotrophic stage (time of seedling dry weight to reach the initial weight of seed). seedling, shoot and root dry weight changing trends were similar in all treatments. however, folic acid application increased the rate of dry weight accumulation in each of the aforementioned plant parts. also, decrease of seed dry weight was similar between control and folic acid treatments, but folic acid application increased the rate of seed reserves consumption in comparison with control.  results showed that seed reserves conversion efficiency to seedling structure in studied treatments were variable in the range of 20-62.96%. the minimum and maximum conversion efficiency belongs to 400 and 25 µm folic acid treatments. the differences between treatments could be due to partitioning manner of seed reserves to growth and/or maintenance respiration. growth and maintenance respiration of the studied treatments were variable in the ranges of 12.12-63.26% and 36.7-87.9%. it can be concluded that folic acid application increases seedling vigor by increasing conversion efficiency and growth respiration of wheat seedling.