Shahed University

Determination of optimum concentration and time of pre-treatment with plant growth regulators on germination indices of Catharanthus roseus seed

Heshmat Omidi | M ababaf | H Bakhshandeh

Date :  2020/04/26
Publish in :    پژوهش هاي بذر ايران

Keywords :Catharanthus roseus, Priming, Jasmonic acid, Salicylic acid,

Abstract :
Extended abstract Introduction: Catharanthus roseus is regarded as a medicinal ornamental plant. This plant has anti-cancer, anti-hypertensive, anti-diabetes, and antimicrobial properties. Catharanthus has a fairly long vegetative period due to its slow initial growth. The long growth period of the plant is considered as one of the limitations of its cultivation on larger scale. By using plant growth regulators such as salicylic acid (SA) in the imbibition phase and pre-treatment, increase in seed activity and the seedling growth of many crops is observable. Also, Jasmoninc acid (JA) plant growth regulator play an important role in seed germination and plant growth. Regarding the long growth period of this plant, the small size of the seed, and poor establishment in the field with semi-heavy and heavy textured soils, the present study aimed to evaluate the effect of seed priming with SA and JA in different concentrations and periods of time on improving Catharanthus roseus seed germination indices. Materials and Methods: The studies were conducted in order to determinate optimum concentration and time of plant growth regulators to seed priming separatly, in a factorial experiment based on completely randomized design (CRD) with three replications at the Laboratory of Seed Science and Technology of Shahed University, Tehran, in 2017. Treatments included five different concentrations of SA (0, 0.01, 0.1, 0.5, and 1 mM), concentrations of JA (0, 1, 10, and 100 µM) and five periods of time (0, 6, 12, 24, and 48 hours). At the end of the experiment (10 days) traits such as germination percentage, germination rate, mean germination time, mean daily germination, germination value, seed length vigor index, seed weight vigor index, seedling dry weight, shoot dry weight, radicle dry weight, radicle length, shoot length, and seedling length were measured. Results: The results indicated that SA, JA and time were significant on germination percentage, germination speed, mean germination time, mean daily germination, germination value, seedling length, seedling length vigor index, seedling weight vigor index, and radicle dry weight. The best time for pre-treatment with SA was 24 and 48 hours. Among the applied concentrations of SA, 0.5 and 1 mM concentrations showed the best results. In addition, the best time and concentration for pre-treatment with JA was 12 and 24 hours and 10 µM. Conclusions: The results of this study showed that using of SA and JA for seed priming improved seed germination components. In addition to the pre-treatment concentrations of SA and JA, duration of seed the contact with growth regulators is important. It was observed that there was a significant difference among the different priming times, therefore, it can be stated that seed pre-treatment time is one of the important factors of seed priming and determination of proper priming time prevented negative effect of pretreatment on germination and seedling growth in primed seeds.