The effect of sugar beet seed treatments on their vigour

Abstract

Sugar beet seeds of three varieties (Jastra, Jamira, PNMono1) were rubbed, primed, washed and primed after rubbing. All used methods of seed treatment changed pericarp characteristics such as water potential, density, moisture and content of chemicals resulting in electrical conductivity of water extract from the seeds. Seed treatments also improved the ability and rate of germination. Their efficiency was more significant in an excess and shortage of water in germination medium than in optimum water conditions. The lower the initial seed vigour, the larger the vigour improvement. Seed priming had the best effect on the course of germination. Primed seeds were most resistant to different moisture conditions during germination. The largest differences in germination ability after four days in different water conditions were 5.1 and 7.4% for primed and primed after rubbing seeds, respectively, while the difference for control ones was 26.8%. Priming also caused an increase in seed respiration intensity. Rubbing and washing removed chemicals from the pericarp, which resulted in an increase in water potential, and consequently in vigour improvement.Keywords: sugar beet; seeds; germination; vigour; treatment; priming; washing; rubbingThe introduction of monogerm sugar beet varieties and drilling to stand had a catastrophic influence on the plant population through poor establishment. Accordingly, an improvement of the course of germination and field emergence was necessary.A series of experiments was conducted to evaluate the effectiveness of different technologies of pre-sowing treatment of three sugar beet varieties differing in their ploidy level. There was also an attempt to explain the results of seed treatments. This study tries to explain how some fruit properties affect germination and field emergence.Pericarp and botanical seed characteristics determine the properties of sugar beet fruit. The pericarp consists of three layers: the two inner ones consist of thick-wall sclereids containing crystals of salts. In the presence of water they form an osmotic solution which has a low water potential. Just before radicle emergence the level of the water potential of seed pericarp is about -1.0 MPa. If this level is achieved faster, seed germination will be faster (Podlaski and Chrobak 1997) The process of rubbing removes the most porous, outer layer of parenchyma resulting in an increase in pericarp density and removal of a part of chemicals. Similar effects can be obtained by seed washing.In the last years seed companies have exerted an enormous pressure on researchers to develop new, effective technologies of seed quality improvement, especially seed priming. Priming consists in wetting seeds to the moisture level that enables early processes leading to germination but is too low for radicles to emerge. It is obvious that priming changes mostly the properties of botanical seed. In 2002 primed seeds were sown on 30% of the area under sugar beet in Great Britain. As a result an improvement of germination and ...

Optimization of Germination Inhibitors Elimination from Sugar Beet (Beta vulgaris L.) Seeds of Different Maturity Classes

“…In general, these toxic substances can be located in different parts of the fruit (pulp, juice, or coat) or seed (coat, endosperm, or embryo), depending on the species [11]. The operculum and pericarp are the candidate locations of these toxic substances in beets [13][14][15][18][19][20][21].…”

“…Phenols are chemically active and are easily oxidized [26]. The effect of these chemicals is in addition to osmotic properties, caused by salt crystals present in the pericarp [11,12,14,18,21]. Salt crystals in the pericarp can restrict the seed water and oxygen uptake [21].…”

“…The effect of these chemicals is in addition to osmotic properties, caused by salt crystals present in the pericarp [11,12,14,18,21]. Salt crystals in the pericarp can restrict the seed water and oxygen uptake [21]. However, the possibility of severe effects from the high osmotic value is low, due to the halophytic characteristic of sugar beet [12].…”

“…Botanical seed characteristics determine sugar beet seed features. The pericarp is an influential part, the structure of which varies during development [21]. There is some evidence that water absorption by seeds differs due to maturity class, and this can in turn affect the germination potential [13].…”

“…Changing the pericarp water potential and seed moisture content are two possible effects of the washing treatment. However, the initial seed quality and germination potential indicate the efficiency of treatment to assist the woody sugar beet seed in absorbing water, leaching out toxic substances and promoting physiological processes resulting in uniform and fast germination [21,27,28].…”