The Expression of Lea Proteins Pisum Sativum Seeds

C. KLAK 45 PAGES (7755 WORDS) Economics Thesis

AbstractSeeds of Pisum sativum cv. Greenfeast were used in all of

the experiments. In order to prevent imbibitional damage, seeds

were slowly pre-hydrated for 1 hour on damp blotting paper prior

to imbibi tion. In order to ascertain at what stage during

germination the seeds had lost their desiccation-tolerance, seeds

were imbjbed for different intervals (12, 36, 48, 60 hrs) prior

to redrying to their original moisture content at room

temperature (23° C).

SLOW DRYING OF WHOLE SEEDS.

For each imbibitional stage seeds were slowly dried back to

their original moisture content (11. 3 g H20/g dry mass) by

placing them evenly spaced in a laminar flow cabinet. Viability

and moisture content were assessed at time intervals o, 4, 10,

24, 34, 48 hrs by which time the seeds had reached their original

moisture content.

RAPID (FLASH) DRYING OF EMBRYONIC AXES.

Seeds were pre-hydrated as described above. After

imbibition the seeds were removed from the water and the lengths

of their axes were measured as a rough indicator of how far

germination had proceeded. Axes of similar length were selected

for the experiment. The rapid drying of embryonic axes followed

Pammenter et al 's (1991) method: Air was passed at room

temperature (approximately 22° C) through two fish tank air

diffuser• in parallel evenly spaced at the bottom of a plastic

box 10 cm long, 10 cm wide and 4 cm deep. Excised embryonic axes

were placed on fine-mesh nylon supported 2 cm above the air

stones and removed after the required drying time, i.e. 20, 40,

60, 120, 160, 200, 280, 320, 360, 690 minutes until the original

moisture content of the axis was reached. At each time interval,

moisture content (measured as described below for whole seeds)

and viability was assessed as described below.