Agriculture Reference
In-Depth Information
Glucose was the major product of starch degradations. Sucrose,
maltose, maltotriose, raffi nose and fructose were also detected.
Protease activity reached a maximum on the fi fth or sixth day
and closely paralleled the increase in soluble aminoN and
soluble protein (Palmiano and Juliano 1972).
The critical temperature for germination is 17ºC. Germination
and elongation decline rapidly below the critical temperature.
For germination below the critical temperature some differences
in metabolism is inferred.
Studies revealed that the changes in activity of enzymes
in the breakdown of stored phytin, lipid, and hemicelluloses
in the aleurone layer of rice seed (IR8) during the fi rst week
of the germination in the light. Enzyme activities from
degermed seed such as phytase activity increased within fi rst
day of germination. The increase in activity of most other
enzymes—Phosphomonoesterase, phosphodiesterase, esterase,
lipase, peroxidase, catalase, beta-glucosidase and alpha and
beta galactosidase closely followed the increases in protein
content. Their peak activities occurred by the 5th to the 7th
day. Some enzymes, such as beta-1, 3-glucanase and alpha-
amylase, continued to increase in activity after the 7th day.
Phytase, beta-1, 3-glucanase, and alpha amylase followed a
similar sequence of production in embryo less seed halves
incubated in 0.12 nM gibberellins GA3, but the production
of lipase was delayed (Palmiano and Juliano 1973). In a close
parallel to the developmental pattern of a-amylase activity, a
rapid increase of maltase activity occured in the endosperm
tissue of germinating rice seeds after about 4 days of seed
imbibition. Sucrose synthetase activity show that the scutellum
is the site of sucrose synthesis in germinating rice seeds, the
glucose derived from starch in endosperm is transported to
scutellum, where it is converted to sucrose (Fig. 3). Sucrose is
