Seed vigor

Fig. 6.2. Typical changes in soybean seed vigor relative to germinability during storage (Source Nafziger, 2002b).

Effects of Impact Damage and Flooding on Seed Vigor... 

A study by Wuebker et al. (2001) investigated the effect of impact damage on seed vigor with a rotating horizontal cylinder. Each revolution of the cylinder lifted 250 g of seeds with a horizontal paddle and allowed the seeds to drop within the cylinder. Impact damage was assessed visibly by an increase in seed-coat cracks and splits and... 

Ching, T.M. Biochemical aspects of seed vigor. Seed Sci. Technol. 1, 73-88 (1973)... 

Method 2. Place 0-2 g. of cupric acetate, 10 g. of ammonium nitrate, 21 2 g. of benzoin and 70 ml. of an 80 per cent, by volume acetic acid -water solution in a 250 ml. flask fitted with a reflux condenser. Heat the mixture with occasional shaking (1). When solution occurs, a vigorous evolution of nitrogen is observed. Reflux for 90 minutes, cool the solution, seed the solution with a crystal of benzil (2), and allow to stand for 1 hour. Filter at the pump and keep the mother liquor (3) wash well with water and dry (preferably in an oven at 60°). The resulting benzil has m.p. 94-95° and the m.p. is unaffected by recrystallisation from alcohol or from carbon tetrachloride (2 ml. per gram). Dilution of the mother liquor with the aqueous washings gives a further 1 Og. of benzil (4). 

It is over three centuries since cinchona bark came into use in European medicine, and no other natural drug has had so much written about it. There are the stories, sometimes legendary, of its discovery by Europeans, vigorous early discussions of its therapeutic value, the destruction of the S. American cinchona trees to meet the demand for bark, the labours of botanical explorers in collecting seed for the formation of plantations, the establishment and development of these plantations in Ceylon, India and Java, the competition between them, the gradual emergence of Java as the world s most important source of supply of cinchona bark, and the development of the manufacture of quinine sulphate in Europe, the United States and the Tropics. ... 

In our case, sprouting in an effectively aerated water medium was selected as the sprouting method of choice. In our system the sprouts are moving and circulating vigorously with the water flow. Effective aeration is necessary seeds submerged in water without aeration do not sprout and eventually die. Normal tap water or reverse osmosis purified water (RO-water) can be used. 

It is important to monitor the progress of more vigorous plants or those that self-seed in great guantity. Remove as necessary to prevent them from taking over completely. 

While annuals are grown from seed each year (see pp.196-199), perennials and bulbs, if well cared for, should give years of enjoyment. To ensure that you get the best performance from your plants, prepare the soil well, and choose the healthiest, most vigorous specimens. You may be able to find organically grown plants and bulbs, but these are not widely available yet. 

It will cost you nothing, and be fresh, too. Home-saved seed often has a high germination rate and produces vigorous seedlings. 

What to do Encourage quick, vigorous seedling growth. Sow seeds at the right time, prepare the site well, and never let plants go short of water. 

The effect of ozone injury on herbaceous plant reproduction has been mentioned earlier in this chapter and in Chapter 11. Seed production by annuals is influenced mainly by the envirorunental conditions of the current year, but perennial woody plants—particularly conifers—are erratic seed-producers. Intrinsic factors affecting cone production include age and vigor seasonal temperature and soil moisture are important environmental factors. ... 

The effects of sulfur dioxide on cone production have been described by Scheffer and Hedgcock and Pelz. Generally, the decrease in tree vigor caused by the pollutant may eliminate or lower the frequency of cone production and diminish the size, weight, and germination of seed. The effects of chronic ozone injury on conifer seed production may be similar, in that tree vigor is drastically reduced. The effects of chronic ozone injury on ponderosa and Jeffrey pine seed production are under investigation by Luck (in Kickert et al,... 

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