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Title: EFFECTS OF ATMOSPHERIC CO2 ENRICHMENT ON THE GROWTH AND DEVELOPMENT OF HYMENOCALLIS (AMARYLLIDACEAE) AND THE CONCENTRATIONS OF SEVERAL ANTINEOPLASTIC AND ANTIVIRAL CONSTITUENTS OF ITS BULBS

Author
item Idso, Sherwood
item Kimball, Bruce
item PETTIT III, G - CANCER RES, ASU, TEMPE
item GARNER, L - CANCER RES, ASU, TEMPE
item PETTIT, G - CANCER RES, ASU, TEMPE
item BACKHAUS, R - ASU, TEMPE, ARIZONA

Submitted to: American Journal of Botany
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/1/1999
Publication Date: 2/15/2000
Citation: Idso, S.B., Kimball, B.A., Pettit Iii, G.R., Garner, L.C., Pettit, G.R., Backhaus, R.A. 2000. Effects of atmospheric co2 enrichment on the growth and development of hymenocallis (amaryllidaceae) and the concentrations of several antineoplastic and antiviral constituents of its bulbs. American Journal of Botany. 87:769-773.

Interpretive Summary: One aspect of the ongoing rise in the air's carbon dioxide concentration that has received scant attention is the impact it could have on the growth of medicinal plants and their production of therapeutic substances. We thus conducted a four-year study of the effects of a 75% increase in the air's CO2 content on the growth of a tropical spider lily and the concentrations of five chemical constituents of its bulbs that have been demonstrated to be effective in the battle against human melanoma; brain, colon, lung, and renal cancers; as well Japanese encephalitis and yellow, dengue, Punta Tora, and Rift Valley fevers. Our results revealed a 56% CO2-induced increase in spider lily bulb biomass and an 18% CO2-induced increase in the concentrations of the five medicinal bulb constituents. Together, these effects were responsible for an 84% increase in the amounts of therapeutic substances produced by the spider lily plants in response to othe 75% increase in the air's CO2 content, a finding that may have far- reaching implications for both the managed cultivation of these medicinal plants and the roles they play in indigenous societies that depend on natural remedies to maintain their health.

Technical Abstract: We grew two 2-year crops of tropical spider lily (Hymenocallis littoralis) plants in clear-plastic-wall open-top enclosures in the Sonoran Desert environment of central Arizona. Half of the plants were exposed to ambient air of 400 ppm atmospheric CO2 concentration, and half of them were exposed to air of 700ppm CO2. This 75% increase in the air's CO2 content resulted in a 48% increase in above-ground plant biomass and a 56% increase in below-ground (bulb) biomass. It also increased the concentrations of five bulb constituents that have been demonstrated to possess anticancer and antiviral activities. Mean concentration increases were 9% for a two-constituent (1:1) mixture of 7-deoxynarciclasine and 7-deoxy-trans-dihydronarciclasine, 10% for pancratistatin, 21% for trans-dihydronarciclasine, and 32% for narciclasine, for a mean active ingredient increase of 18%. Combined with the 56% increase in bulb biomass, these concentration increases resulted in a mean active ingredient increase of 84% for the 75% increase in the air's CO2 concentration utilized in our experiments.