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Growth response of cotton to CO 2 enrichment in differing light environments
Author(s) -
Rufty Thomas W.,
Thomas Richard B.,
Cure Jennifer D.,
Cure William W.
Publication year - 1994
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1994.tb02980.x
Subject(s) - photosynthesis , horticulture , dry weight , botany , incandescent light bulb , light intensity , shoot , biology , zoology , chemistry , physics , optics
Experiments were conducted to examine the growth responses of cotton ( Gossypium hirsutum L. cv. Coker 315) to CO 2 enrichment under different light regimes. Plants were exposed to 350 or 700 μl l −1 CO 2 and six light treatments differing in photosynthetic period length (8 or 16 h) and in photosynthetic photon flux density (PPFD) for 32 days of vegetative growth. Higher PPFD (1 100 μmol m −2 s −1 ) was provided by a combination of high intensity discharge and incandescent lamps (HID), and lower PPFD (550 μmol m −2 s −1 ) was provided by fluorescent and incandescent lamps (F) or HID and incandescent lamps with shade cloth (HID s ). Growth was generally much slower with the 8‐h photosynthetic periods, but the growth stimulation by CO 2 enrichment was larger than with 16‐h photosynthetic periods. After 28 to 32 days of treatment, the growth enhancement with CO 2 enrichment was 152 and 78% for 8‐ and 16‐h photosynthetic periods, respectively, under HID; 100 and 77% in F, and 77 and 56% in HID s . The higher PPFD of HID positively influenced the CO 2 effect only at the slower growth rate in the 8‐h light period. The stimulation of leaf area expansion by CO 2 enrichment was also greater with the 8‐h photosynthetic period for all light sources. These results, and others on net assimilation rate, shoot to root dry weight ratios and specific leaf weights, suggest that the growth response to CO 2 enrichment with the longer photosynthetic period was depressed by limiting factors, perhaps nutritional, in the growth environment. The results also show that extensive variability in CO 2 response can occur under light intensities which are often used in growth chamber experiments.