RESPIRATION LEVEL OF SUGAR BEET SEEDS AS A ONE OF METHODS OF VIGOUR ESTIMATION

Mgr. ing. Aleksandra Orzeszko-Rywka, dr. Malgorzata Rochalska

Department of Plant Breeding and Seed Science

Warsaw Agricultural University

Summary

The effect of 7 different methods of sugar beet seed treatment on vigour an seed quality was examined. All applied methods increased germination ability and germination speed. However only treatments influencing true sugar beet seed inside pericarp caused an increase of respiration level.

Streszczenie

Badano wpływ różnych sposobów poprawy jakości materiału siewnego na wigor nasion buraka cukrowego. Stwierdzono, że wszystkie stosowane metody poprawiają zdolność kiełkowania i przyśpieszają kiełkowanie nasion. Natomiast oddychanie nasion zwiększają jedynie metody mające wpływ na zawarte w owocni właściwe nasienie buraka cukrowego.

Introduction

Treatments improving sugar beet seeds quality can be divided into two groups. First one consists on changing of the structure of pericarp. Here belong rubbing and washing of the seeds. To the second group of methods belong conditioning and magnetic field treatment which influence directly the true seed inside the pericarp. There are also methods combining elements from both groups like rubbing with conditioning or with magnetic field treatment.

Level of respiration of seeds and its changes at the beginning of the germination can be a good indicator of seed vigour.

Material and methods

Sugar beet seeds of 3 varieties were taken from Sugar Beet Breeding Station in Kutno. Varieties PN Mono 1 and Jastra were diploid and Jamira was triploid. The most numerous seed fraction ( 3,5-4 mm seed diameter) was used in the examination. Seed samples were prepared in different ways: rubbed, washed, conditioned, treated with low frequency magnetic field (16Hz), rubbed in combination with conditioning, rubbed in combination with magnetic field treatment and conditioned in combination with magnetic field treatment.

Seed respiration was measured with LICOR - 6200, an appliance produced by LICOR Company, Nebraska USA. Respiration was measured during three subsequent days in the beginning of seed germination in optimum water content in germination medium (65%, according to Polish Norm PN-79/R-65950) and temperature 20° C. Results of seed respiration are shown as an average from 3 varieties. Some differences in respiration level among varieties were observed.

Moreover, seed vigour was estimated in more traditional way. All the combinations were examined regarding their germination ability (%) and rate of germination of one seed (Piepers coefficient - number of days) after 4 days of germination under optimal conditions. The germination tests were done by both authors separately. Because of differences in the values they results are shown in separate tables.

Results

Tab.1 Respiration of seeds during first 3 days of germination

The lowest respiration values for all combinations were observed on 1st day of experiment. Average level of the respiration was increasing during 3 days of experiment. But two combinations: conditioned seeds and conditioned + treated with magnetic field seeds reached maximum on 2nd day of germination. Two others: rubbed + conditioned and rubbed + treated with magnetic field showed very slight increase between 2nd and 3rd day of experiment. Seeds of these four combinations started their germination earlier. Results of germination tests are shown in tab.2 and tab.3.

Tab. 2 Germination ability and Piepers coefficient after 4 days of germination (A.Orzeszko-Rywka)

Tab. 3 Germination ability and Piepers coefficient after 4 days of germination (M.Rochalska)

Four combinations showing the earliest maximum of respiration level had higher speed of germination of one seed (lower level of Piepers coefficient). Other treatments like washing or rubbing influencing structure of pericarp, but not the seed itself, improved germination ability and its speed but didnt influence the level of respiration.

Conclusions

· All examined methods of seed treatment increased seed vigour measured in traditional way (germination ability, Piepers coefficient).

· Best results were obtained for conditioned and conditioned + treated with magnetic field seeds.

· Only methods influencing directly seed inside the pericarp (conditioning, conditioning + 16 Hz treatment, rubbing + conditioning, rubbing + 16 Hz treatment) increased significantly seed vigour measured by means of respiration level.

· Magnetic field treatment influenced level of respiration in a different way in each variety. The differences cancelled each other in average.

· Some hypothesis link loss of seed vigour with a damage of cell membrane. It is possible that non-mechanical methods of seed treatment act on the membrane level.

· Methods of pre-sowing sugar beet seed treatment can be divided into 2 main categories:

1. Methods of mechanical changing of pericarp structure (rubbing, washing)

1. Methods influencing seed (or embryo) physiology (conditioning, magnetic field treatment)

Mechanisms of these 2 groups of methods must be considered separately.

References

1. Alexander, M., P., Doijode, S., D.,1995 Electromagnetic field - a novel tool to increase germination and seedling vigour of onion and rice seeds with low viability. Plant Genetic-Resources Newsletter 104, 1995, 1-5.

1. Orzeszko A., 1996 Metody umożliwiające wcześniejszy siew nasion i poprawę wschodów polowych buraków cukrowych. Hodowla Roślin i Nasiennictwo. Biuletyn branżowy 2 s.12-16

2. Podlaski S., Chrobak Z., 1997 Fizyczne podstawy kiełkowania nasion buraków cukrowych, Biul. IHAR Nr 202, s 55-61

3. Priestley, D.,A., 1986 Seed ageing. Constock Publ. Ass., London