The changes of chlorophyll_protein complexes and photosynthetic activities of chloroplast isolated from lotus ( Nelumbo nucifera Gaertn.) seeds germinating under illumination were studied. SDS PAGE analysis of c...The changes of chlorophyll_protein complexes and photosynthetic activities of chloroplast isolated from lotus ( Nelumbo nucifera Gaertn.) seeds germinating under illumination were studied. SDS PAGE analysis of chlorophyll_protein complexes showed that there was only the light harvesting chlorophyll a/b protein complex from PSⅡ (LHCⅡ) precursor in chloroplast from lotus seeds germinated for 2 to 6 days, while LHC Ⅱ 1, and the chlorophyll_protein complex of PSⅠ (CPⅠ) appeared on the 8th day of germination and PSⅡ reaction center complex appeared later. Studies on the polypeptides composition of the chloroplast revealed the following results: 1) Small amount of the 27 kD polypeptide was synthesized in invisible light; 2) The 30 kD polypeptide existed previously in the plumules of the dry seeds; 3) The amount of the 30 kD polypeptide was more than any other polypeptides before germination and decreased gradually throughout germination, while the 27 kD polypeptide changed in the opposite way; 4) In the process of germination, measurement of the electron transport rate and the fluorescence induction kinetics at room temperature showed that PSⅡ activities and efficiency of primary light energy transformation were only experimentally measurable after 7 days of germination and gradually increased afterwards. At the same time, the chl a/b ratio rose from the lower value to normal; 5) The changes of chloroplast membrane components and its functions are concomitant in concert with that of the ultrastructure of chloroplast membranes during germination, as shown in our earlier work . The results have proved again that a different developmental pathway of chloroplast is likely to exist in the lotus plumules, which might provide an important clue for N. nucifera in having an unique position in the phylogeny of the angiosperm.展开更多
Ethylene was tested as a sprout inhibitor on potatoes intended for processing over the 2006-2007 and the 2007-2008 storage seasons. Russet Burbank, Shepody, Innovator, FL-1867, and FL-1833 were loaded into the Univers...Ethylene was tested as a sprout inhibitor on potatoes intended for processing over the 2006-2007 and the 2007-2008 storage seasons. Russet Burbank, Shepody, Innovator, FL-1867, and FL-1833 were loaded into the University of Maine potato research facility in October of 2006. Ethylene gas was metered into the storage until a concentration of 0.1 ppm was reached and then held for one week. At weekly intervals, the ethylene concentration was increased to 0.3 ppm, 0.6 ppm, 12 ppm, 5.0 ppm and 102 ppm. Subsequently, the concentration was maintained at 10.0 ppm for the duration of the storage season. Control potatoes received chlorpropham （CIPC） for sprout control. The trial was repeated in the 2007-2008 storage season. The Agtron readings were performed on the processed potatoes at the end of the storage season. There was no difference in the US color grade between the CIPC-treated and ethylene-treated tubers within any tested variety in either storage season. Sprout inhibition of the ethylene-treated potatoes was acceptable for normal storage length of the potato varieties tested. Ethylene may have promise as an alternate to CIPC for sprout control in potato storages.展开更多
文摘The changes of chlorophyll_protein complexes and photosynthetic activities of chloroplast isolated from lotus ( Nelumbo nucifera Gaertn.) seeds germinating under illumination were studied. SDS PAGE analysis of chlorophyll_protein complexes showed that there was only the light harvesting chlorophyll a/b protein complex from PSⅡ (LHCⅡ) precursor in chloroplast from lotus seeds germinated for 2 to 6 days, while LHC Ⅱ 1, and the chlorophyll_protein complex of PSⅠ (CPⅠ) appeared on the 8th day of germination and PSⅡ reaction center complex appeared later. Studies on the polypeptides composition of the chloroplast revealed the following results: 1) Small amount of the 27 kD polypeptide was synthesized in invisible light; 2) The 30 kD polypeptide existed previously in the plumules of the dry seeds; 3) The amount of the 30 kD polypeptide was more than any other polypeptides before germination and decreased gradually throughout germination, while the 27 kD polypeptide changed in the opposite way; 4) In the process of germination, measurement of the electron transport rate and the fluorescence induction kinetics at room temperature showed that PSⅡ activities and efficiency of primary light energy transformation were only experimentally measurable after 7 days of germination and gradually increased afterwards. At the same time, the chl a/b ratio rose from the lower value to normal; 5) The changes of chloroplast membrane components and its functions are concomitant in concert with that of the ultrastructure of chloroplast membranes during germination, as shown in our earlier work . The results have proved again that a different developmental pathway of chloroplast is likely to exist in the lotus plumules, which might provide an important clue for N. nucifera in having an unique position in the phylogeny of the angiosperm.
文摘Ethylene was tested as a sprout inhibitor on potatoes intended for processing over the 2006-2007 and the 2007-2008 storage seasons. Russet Burbank, Shepody, Innovator, FL-1867, and FL-1833 were loaded into the University of Maine potato research facility in October of 2006. Ethylene gas was metered into the storage until a concentration of 0.1 ppm was reached and then held for one week. At weekly intervals, the ethylene concentration was increased to 0.3 ppm, 0.6 ppm, 12 ppm, 5.0 ppm and 102 ppm. Subsequently, the concentration was maintained at 10.0 ppm for the duration of the storage season. Control potatoes received chlorpropham （CIPC） for sprout control. The trial was repeated in the 2007-2008 storage season. The Agtron readings were performed on the processed potatoes at the end of the storage season. There was no difference in the US color grade between the CIPC-treated and ethylene-treated tubers within any tested variety in either storage season. Sprout inhibition of the ethylene-treated potatoes was acceptable for normal storage length of the potato varieties tested. Ethylene may have promise as an alternate to CIPC for sprout control in potato storages.
