The Effect of Different Treatments on Seed Dormancy Breaking of Weed Stalked Bur Grass Tragus racemosus (L.) AlI.

پژوهش های حفاظت گیاهان ایران

Article 9, Volume 30, Issue 3 - Serial Number 33, September 2017, Pages 541-546   

Document Type: Research Article

DOI: 10.22067/jpp.v30i3.46144

Authors

Gholam reza doraki^* ; Gholam reza Zamani

University of Birjand

Abstract

Introduction: Stalked Bur Grass (Tragus racemosus L.) is an angiosperm annual plant with C4 photosynthesis pathway and stolon. It grows in hot and dry summers. This plant spreaded throughout the world from hot regions of Africa. It is regularly seen in barren lands or in between the generations with sequential initial stages with light-texture soils. Seed dormancy is in fact a physiological phenomenon which is observed in the seeds of most crops, pasture plants, medicinal herbs and weeds. Dormancy allows the plant to guarantee its germination and survival for long years and to survive through adverse environmental conditions through its spatial and temporal spread.
Materials and Methods: In order to evaluation dormancy break of Tragus racemosus L. seeds, an experiment was carried out based a Randomized Complete Block Design with four replications in research laboratory of Department of Agriculture, Birjand University during 2013. The initial experiments showed that the seeds of Stalked Bur Grass had initial dormancy and were unable to germinate at normal conditions, so that less than 5% of the seeds germinated. The studied treatments for breaking seeds dormancy included control (seeds disinfection by distilled water), wet chilling at 4°C for 1, 2, 3 and 4 weeds, treatment with H2SO4 at 97% for 20, 40, 60 and 80 seconds, treatment with KNO3 at 0.2, 0.4, 0.6 and 0.8% for 24 hours and treatment with Gibberellic acid (GA3) at 50, 100, 200 and 400 ppm. In this study, 25 seeds of Stalked Bur Grass were uniformly placed in petri dishes with the diameters of 9 cm on Watmann filter papers and were applied with 5 mL distilled water. The number of germinated seeds was counted on a daily basis for 21 days. In the end, germination percentage and rate was determined.
Results and Discussion: The results revealed that the effect of all studied levels of all treatments were significant on germination percentage and rate. The highest germination percentage (76%) was observed under wet chilling treatment at 4°C for 4 weeds and the lowest one (6%) was observed in control. The highest germination percentage under H2SO4 treatment was 41% obtained at the level of 80 seconds, under KNO3 treatment was 69% obtained at the level of 0.8%, and under GA3 treatment was 62% obtained at the level of 400 ppm. The highest germination rate (18.24 seeds per day) was observed at KNO3 treatment (0.8%) and the lowest one (0.91 seeds per day) was observed in control. In addition, the highest germination rate under H 2SO4 treatment was 15.28 seeds per day obtained at the level of 80 seconds, under wet chilling was 13.25 seeds per day obtained at the level of 3 weeks, and under GA3 treatment was 12.08 seeds per day obtained at the level of 200 ppm. Wet chilling enhances the production of such stimulants as gibberellins. On the other hand, chilling treatment may reduce ABA amount or the sensitivity of embryo to ABA which can play a role in seeds dormancy breaking. KNO3 is likely to increase the sensitivity of germinating seeds to light acting as a complement factor for phytochrome which results in higher germination of the seeds. Most researchers believe that dormancy is broken by the balance between growth inhibitors like abscisic acid and growth stimulators like gibberellins. In addition, gibberellins activate a special signaling pathway that reduces abscisic acid in seeds and in contrast, auxins and cytokinins of the seeds are increased to a level enough for inducing dormancy break.
Conclusion: In the present study, the germinated seeds were counted for 21 days. The highest germination percentage (76%) was observed under wet chilling treatment for 4 weeks and the lowest one (6%) was observed under control treatment. The highest germination rate (18.24 seeds per day) was observed under KNO3treatment (0.8%) and the lowest rate (0.91 seeds per day) was reported under control treatment. According to the results it can be concluded that the dormancy of Stalked Bur Grass seeds belongs to physiological dormancy type.

Keywords

Germination percentage; Gibberellic acid; Moist chilling; Potassium nitrate; Sulfuric acid

References

1- Adkins S.W., Bellairs S.M., and Loch D.S. 2002. Seed dormancy mechanisms in warm season grass species. Euphytica, 126: 13-20.

2- Charkhchian M.M., Akbarinia A., and Abtahi F. 2009. A contribution to the flora of Alamut area, Qazvin ,Iran. Pajouhesh and Sazandegi, 81: 111-125. (in Persian with English abstract).

3- Chiwocha S.D.S., Culter A.J., Abrams A.J., Ambrose S.J., Yang J., Ross A.R.S., and Kermode A.R. 2005. The ert1- 2 mutation in arabidopsis thaliana affects the abscisic acid, auxin, cytokinin and gibberellin metabolic pathways during maintenance of seed dormancy, moist chilling and germination. The Plant Journal, 42:35-45.

4- Ehyaee H.R., and Khajeh Hosseini M. 2012. Assessment of seed germination and dormancy of thirty seeds lots of. Iranian Journal of Field Crops Research, 9(4): 651-658. (in Persian with English abstract).

5- Ghasemi Pirbalouti A., Golparvar A.R., Riyahi Dehkordi M., and Navid A.R. 2007. The effect of different treatments on seeds dormancy and germination of five species of medicinal plants of Chahar Mahal & Bakhteyari province. Pajouhesh and Sazandegi, 74: 185-192. (in Persian with English abstract).

6- Hitchcock A.S. 1950. Manual of the grasses of the United States. 2nded. U.S. Department of Agriculture Miscellaneous Publication No. 200. USDA, Washington, USA. 1051 p.

7- International Seed Testing Association. 1979. The germination test. Seed Science and Technology, 4: 23-28.

8- Kalapos T., Boogaard R.V.D., and Lambers H. 1996. Effect of soil drying on growth, biomass allocation and leaf gas exchange of two annual grass species. Plant and Soil, 185:137-149.

9- Karam N.S., and AL-Salem M.M. 2001. Breaking dormancy in arbutus andrachne L. seeds by tratification and gibberelic acid. Seed Science and Technology, 29: 51-56.

10- Kargar M., Hosseini M., and Rashed Mohassel M.H. 2013. Effects of different treatments on breaking of dormancy and seed germination of littleseed Canarygrass (Phalaris minor Retz.). Journal of Plant Protection. 27(1): 128-134. (in Persian with English abstract).

11- Khajeh-Hossini M., Lomhololt A., and Matthews S. 2009. Mean germination in the laboratory estimates the relative vigour and fild performance of commertial seeds lots of maize (Zea mays L.). Seed Science and Technology, 37: 446-456.

12- Li W., McDonald M.B., Bennett M.A., and Kwong F.Y. 2005. Hydropriming of differing sized impatiens "Expo wine" seeds. Seed Science and Technology, 33: 639-646.

13- Meusei H., Jager E., and Weinert E. 1965. Vergleichende Chorologie der Zentraleuroptiischen Flora. Band I. VEB Gustav Fischer Verlag, Jena, Germany, 583 p.

14- Naba'ee M., Roshandel P., and Mohammad Khani A. 2013. The effects of plant growth regulators on breaking seed dormancy in silybum marianum L. Journal of Cell and Tissue. 4(1): 45-54. (in Persian with English abstract).

15- Nichols M.A., and Heydecker W. 1968. Two approaches to the study of germination data. Proccedings of the International Seed Testing Association, 33:531-540.

16- Nicolas C., Nicolas G., and Rodriguez D. 1996. Antagonistic effects on abscisic acid and gibberellic acid on the breaking of dormancy of Fagus sylvatica seeds. Physiologia Plantarum, 96: 244-250.

17- Pouresmail M., and Sharifi M. 2003. Dormancy-breaking in Bunium persicum seeds by stratification and some cytokinines. Medicinal and Aromatic Plant Research, 19(2): 183-193. (in Persian with English abstract).

18- Schmitz N., Xia J.H., and Kerrmode A.R. 2001. Dormancy of yellow Cedar seeds is terminated by gibberllic acid in combination with fluridone or with osmotic priming and moist chilling. Seed Science and Technology, 29: 331-346.

19- Tajbakhsh M. 1996. SEED (Study, Control and Certification). Ahrar Publications, Tabriz.