CRANBERRY STATION. 167 



floodings are about the longest in the year. In clear weather they allow 

 photosjTithesis to go on about fifteen hours of the twenty-four, the oxj'^gen 

 in the water thus being replenished three-fifths of the time. 



From what is known about the efifect of temperature with other species, ' 

 a rise of 18° F. must more than double the rate of respiration in the new 

 growth of cranberry. Therefore a combination of very cloudy weather 

 with a high water temperature seems especially dangerous in the flooding 

 of actively growing vines; for, while the stopping of photosynthesis allows 

 the oxygen in the water to become much reduced, the high temperature 

 greatly increases the need of the plants for oxygen. This was the weather 

 combination of June 17. As already stated, the day was darkly cloudy. 

 It was also warm for a cloudj^ day, the temperature at the station bog 

 reaching 77° F.; also, as the 14th, 15th and 16th had been warm days 

 with warm nights, the water must have become quite warm before it was 

 put on the bog. That warm water is not notably harmful in cranberry 

 flooding in clear weather is explained bj' the fact that a rise in tempera- 

 ture, with light abundant, increases the rate of photosynthesis almost as 

 much as that of respiration. ^ 



Water Injuries to Cranberry Buds. 



When, in flooding, cranberry blossom buds are hurt by drowning (lack 

 of oxygen) they usually are either entirely killed, the whole bud turning 

 bro"ftTi and never opening, or they are injured only on one side, in which 

 case the point of the bud soon bends toward the hurt side, and one or two 

 lobes of the corolla commonly turn brown. When but one side of the bud 

 is hurt it usually opens to form an imperfect blossom, but rarelj^ develops 

 a berry. ^ When this drowning injury occurs it is severest in the deepest 

 water and on the sides of the ditches. 



Another bud injury was observed in 1919 in connection with the flood- 

 ing of three bogs located near together. The berries on these bogs are 

 Early Black, and the water for flooding them all has the same source. All 

 three bogs were flooded before sunrise June 12. The water was let off the 

 two lower ones on the night of June 13, the flooding having lasted about 

 forty-two hours and both days having been clear. The night of June 13 

 was cold, the temperature at near-by bogs falling to 33° F. The water on 

 the upper bog was held until the night of June 14, the flooding period being 

 about seventj^-two hours. 



These bogs were examined a few days later. Most of the buds on the 

 two lower ones showed a pecuhar injury, their tips having turned dark 

 red or blackish and having opened somewhat. In this condition they had 



1 Van't Hoff: Studies in Chemical Dynamics, trans, by Ewan, 1896, p. 126. Kuijper: Rec. 

 Trav. Bot. Nderl., 7: 131-239, 1910. Gore: U. S. Dept. Agr., Bur. of Chem., Bui. No. 142, 1911, 

 pp. 5-28. 



2 Matthaei; Phil. Trans. Roy. Soc, B, 197: 47-105, 1905. 



» As might t)e expected, for the pistil respires faster than any other part of the flower. Maige : 

 Ann. Sci. Nat., Bot., Ser. 9, 14: 1-62, 1911. 



