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Comparison of two measures of PSI electron transport in winter rye

The number of P700 (the reaction centre of Photosystem I) converted to P700+, in winter rye, was determined by measuring the absorbance change at 820nm . It was found, with a single turnover flash, that thylakoids isolated from cold grown plants have a 50% greater number of P700 oxidized than thylakoids isolated from warm grown plants. Incubation of thylakoids in the dark at 35 C did not change the number of P700 oxidized. The conversion of P700 to P700+ with a single flash can be compared to a steady state rate of electron transport using a Clark electrode. The results for P700 oxidation using the absorbance change at 820 nm measure effects within the PSI complex whereas the results obtained from a Clark electrode measures steady state electron transport between the cytochrome blf complex and the PSI complex. In contrast to the results for P700 oxidation it was shown, using a Clark electrode, that both thylakoids from cold grown plants and thylakoids incubated at in the dark 35 C exhibited 50% higher rates of electron transport than thylakoids from warm grown plants. The correlation between the higher rate of steady state PSI electron transport observed in thylakoids isolated from cold grown winter rye and number of active PSI reaction centres localizes the site of the increase to the PSI reaction centre. In contrast the lack of correlation after incubation at 35 C indicates the increase in the rate of light saturated electron transport in thylakoids isolated from cold grown plants and thylakoids incubated in the dark at 35 C occur by different mechanisms.

Daniel Shannon fonds, 1816-1822

Lt. Daniel Shannon fl. 1777-1822, was the only son of Susan Drake, granddaughter of Rev. Thomas Drake, eldest brother of Sir Francis Drake, and Captain Daniel Shannon of the Royal Navy. He married Elizabeth Garvey, daughter of Alexander Garvey and Catharine Borden of New Jersey. Lt. Shannon was a Regular in the British Army and on February 12, 1777 he joined the Royal Standard, 5th New Jersey Volunteers. After being arrested and sentenced to hang for spying he was pardoned through the efforts of his mother Susan Drake Shannon who pleaded his case with the Governor. He served under General Cornwallis at the surrender in Virginia in 1781. In 1783 he moved to New Brunswick, Canada where he was reduced to a half-pay ensign in the 2nd Regiment of the Lincoln Militia. He was granted 500 acres of land on the St. Johns River, and on April 1, 1786 his daughter Catharine was born there. The family returned to the United States, residing in Pennsylvania, for a short time. In 1800 Lt. Shannon, with his mother and family, returned to Canada and settled in Stamford Township where he bought 200 acres of land on the Niagara River near the whirlpool. He later served in the Secret Service during the War of 1812 and was stationed at a lookout point on the Niagara River below the falls. In 1806 Shannon’s daughter, Catharine, married Thomas Lundy, fourth son of William Lundy of Stamford Township.