ISSN:
1432-0703
Source:
Springer Online Journal Archives 1860-2000
Topics:
Energy, Environment Protection, Nuclear Power Engineering
,
Medicine
Notes:
Abstract Two-yr-oldPinus strobus seedling shoots were exposed to pH 5.6, 4.6, 3.6, and 2.6 mists, nightly during a 24-wk period coinciding with the growing season. Throughout the misting period, seedlings were well-fertilized and mist water was excluded from the soil of each seedling in order to render inconsequential the higher nutritional content (NO3 − and SO4 2−) of the more acidified mists. Foliar necrosis appeared in all plants exposed to acidity levels below pH 5.6. Injury magnitude and quantity was pH-dependent, ranging from no injury of the pH 5.6 needles to more than 50% injury of needle tissue from the pH 2.6 group. No significant differences were observed in the macroscopic growth of seedlings between the four different treatment groups. This was determined through measurements of both the seasonal increase in seedling heights and the fascicle lengths at the end of the season. In addition, no statistically significant differences were found at the microscopic level after the measurement of whole-needle transectional areas of healthy-appearing, green needle segments. Areas of component regions in these transections also did not yield statistical differences. These microscopic results combined with the fascicle length measurements lead to the conclusion that needle elongation progressed in a normal, unaffected manner despite needle injury.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01056214
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