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| | Taisma, María Angélica and Herrera, Ana Drought under natural conditions affects leaf properties, induces cam and promotes reproduction in plants of talinum triangulare Talinum triangulare is a perennial, deciduous shrub commonly found in tropical seasonally-dry environments. In this study an integrative assessment of the responses of this species to drought is provided. Water availability was manipulated under natural conditions and seasonal changes followed in a range of leaf characteristics and reproductive output. The leaf responses measured included rolling, paraheliotropic movements, increase in reflectance and induction of Crassulacean acid metabolism (CAM). Plants growing in a seasonally dry location and subjected to the natural rain regime were studied for approximately one year; 30 plants of this population were frequently watered. Nocturnal acid accumulation and leaf rolling, angle and reflectance were higher throughout the year, except during the rainy season, in plants receiving the natural water supply than in watered plants. The former had a higher production of flowers and fruits than experimentally watered plants. No significant differences between the two groups of plants were found in the frequency of pollinator visits. Leaf angle, rolling and reflectance, and the ratio reproductive mass/leaf mass showed positive correlations with night-time acid accumulation (r2=0.83, 0.64, 0.59 and 0.64, respectively). The reproductive mass/leaf mass ratio was positively correlated with leaf rolling (r2=0.51) and leaf reflectance (r2=0.79) but not with leaf angle. Results suggest that drought causes the increase in leaf angle, rolling and reflectance, as well as CAM activity, and serves as a cue for the increase in fecundity in plants of T. triangulare growing in the field.. INCI, May 2003, vol.28, no.5, p.292-297. ISSN 0378-1844
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