Conservation of Vriesea flammea L.B.Sm., an endemic Brazilian bromeliad: effects of nutrients and carbon source on plant development

Demographic structure across all known populations of the rheophyte Dyckia brevifolia Baker (Bromeliaceae) in the Itajaí-Açu River, Southern Brazil

Understanding the distribution and demographic structure of populations is essential for species conservation. In Brazil, the rheophyte group has been greatly affected by the construction of hydroelectric dams. All know populations of Dyckia brevifolia Baker along Itajaí-Açu River were studied. The plants were classified as seedlings, immature or reproductive rosettes. In addition, the number of dead rosettes, except for seedlings, was determined in five populations of D. brevifolia. The total number of rosettes per population ranged from 273 to 7,185, totaling 30,443 rosettes, and 1,789 seedlings (5.9%). Only 2.4% of rosettes occurred isolated and 97.6% occurred clumped into 2,254 clumps. The number of rosettes per clump ranged from two to 339 rosettes. The percentage of reproductive rosettes per population ranged from 7.8 to 26.7%. The correlation between the number of clumps or between the total number of rosettes and the area of occupation was significant and positive (r = 0.82; P < 0.05). The production of offshoots (1-4) occurred on immature and reproductive rosettes. Dyckia brevifolia has herbivory by Hydrochaeris hydrochaeris (capybara). These rosettes die or often resprout, emitting from 1 to 20 shoots. The populations did not present a pattern of distribution of rosettes in the diametric classes, but in all populations a decrease in the number of rosettes can be observed in the classes with the largest diameter. The small area of occupation (9,185 m2) showed high environmental specificity and vulnerable to habitat loss and environmental changes. Therefore, the maintenance these sites is essential for the long-term conservation of D. brevifolia.

Brassavola tuberculata Hook.: in vitro growth and ex vitro establishment as a function of the micropropagation system and sucrose

This study examines the in vitro growth and ex vitro establishment of Brassavola tuberculata in relation to the micropropagation system and sucrose concentration employed in the in vitro culture. A completely randomized experimental design was utilized, employing a 2 x 5 factorial arrangement. The experimental period began with seedlings cultivated in vitro for 180 days, which were subsequently transferred to Murashige and Skoog culture media containing sucrose concentrations of 0, 15, 30, 45, or 60 g L-1. The cultures were subjected to two micropropagation systems: conventional and gas exchange. After 90 days of in vitro cultivation, the plants were evaluated, transplanted into a substrate, and placed in a screened nursery for ex vitro cultivation. After 300 days of ex vitro cultivation, the survival and initial characteristics of the plants were assessed. The micropropagation system allowing gas exchange and sucrose concentrations up to 30 g L-1 enhanced the shoot and root growth of in vitro propagated plants. No noticeable anatomical differences were observed after 90 days of in vitro culture among the different sucrose concentrations and micropropagation systems used. In the ex vitro establishment, irrespective of sucrose concentration, the micropropagation system facilitating gas exchange positively influenced all evaluated characteristics.