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Effects of long‐term exposure to elevated CO 2 and increased nutrient supply on bracken ( Pteridium aquilinum )
Author(s) -
Caporn S. J. M.,
Brooks A. L.,
Press M. C.,
Lee J. A.
Publication year - 1999
Publication title -
functional ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.272
H-Index - 154
eISSN - 1365-2435
pISSN - 0269-8463
DOI - 10.1046/j.1365-2435.1999.00013.x
Subject(s) - pteridium aquilinum , bracken , nutrient , biology , frond , dry weight , photosynthesis , fern , botany , growing season , zoology , agronomy , ecology
1. Bracken ( Pteridium aquilinum ) is an important fern with a global distribution. Little is known of the response of this species to elevated CO 2 . We investigated the effects of high CO 2 (570 compared with 370 μmol mol –1 ) with and without an increased nutrient supply (a combined N, P, K application) on the growth and physiology of bracken, growing in containers in controlled‐environment glasshouses, over two full growing seasons. Results of growth and physiology determinations are reported for the second season. 2. Elevated CO 2 had little impact on the growth or allocation of dry mass in bracken. No significant changes were detected in dry mass of the total plant or any of the organs: rhizomes, roots and fronds. In contrast to the small effects of high CO 2 , the high nutrient treatment caused a three‐fold stimulation of total plant dry mass and an increase in the allocation of dry mass to above ground when compared with low nutrient controls. 3. Net photosynthetic rates in saturating light were increased by both high CO 2 and nutrient treatments, particularly in spring months (May and June). Growth in elevated CO 2 did not cause a down‐regulation in light‐saturated rates of photosynthesis. The increased carbon gain in the high CO 2 treatments was accompanied, in the low‐nutrient plants, by higher concentrations of carbohydrates. However, in high‐nutrient plants the CO 2 treatment did not cause an accumulation of carbohydrates. The absence of a growth response to elevated CO 2 in bracken despite significant increases in photosynthesis requires further investigation.