Gayana Botanica

Chondrilla juncea L. (Asteraceae) a new plant for the alien flora of Chile

Nicol Fuentes — 2024-06-30

Introduced species pose a potentially significant threat to local biodiversity. In this study, we report Chondrilla juncea L. (Asteraceae) as a new naturalized alien plant in Chile. We provide detailed description, photographs, coordinates sites and discussed potential impacts.

Hard bottom macroalgae communities: spatial distribution in the reef lagoon of Chinchorro Bank, Mexico

Daniel Torruco — 2024-06-30

Hard-bottom macroalgae were analyzed in 17 sites of the reef lagoon of Chinchorro Bank Biosphere Reserve. 36 species were recorded. Canistrocarpus cervicornis was the dominant species. The diversity intervals were between 1.5 and 3.31 bits·ind^-1, the most diverse area was in the southern part of the lagoon where there was a greater presence of coral substrates. The similarity of the sites obtained with the Morisita index, presents diverse and heterogeneous groups that typify specific areas within the reef lagoon, mainly those near windward. Canonical analysis shows the dependence of sites on environmental factors; However, salinity and surface temperature are restrictive for hard-bottom algae. There is a high correlation greater than 0.9 between the environmental parameters and the first three main components of the system.

Rediscovery of Argemone crassifolia G.B. Ownbey (Papaveraceae) considered extinct

Sergio T. Ibáñez — 2024-06-30

Argemone crassifolia G.B.Ownbey is a species of conservation interest for the flora of Chile, as it is known only from its type specimencollected in the Atacama Region in 1925. After almost a century since its discovery, and in the absence of current collections, it wasclassified as “extinct” by the Ministry of Environment of Chile. This work aimed to obtain a record of this species through searches in thelocality where I. M. Johnston collected the type specimen, Quebrada Cañas, within the province of Copiapo. With the informationobtained from this record, the original description is complemented, details about its ecology are provided, and a new conservation category is proposed. Finally, the possible systematic and conservation implications of this discovery are discussed.

Reproductive variation and germination capacity of Tillandsia landbeckii Phil. in the southernmost Tillandsia dune of the Atacama Desert

Andrea P. Loayza — 2024-06-30

Tillandsia landbeckii Phil. is a rootless epiphyte that grows on dunes of the Atacama Desert. There is little information on its naturalhistory, particularly concerning its reproductive ability. To better understand whether sexual reproduction can contribute torecruitment in T. landbeckii, we examined its basic reproductive traits and developed a germination protocol. We marked andcensused plants, as well as collected seeds from four localities along an inland-coast gradient of the southernmost Tillandsia dunein Chile. Seeds were tested for viability and used for germination trials using four culture mediums. Plants vary in size, capsulesize and number of seeds per capsule along the gradient, with larger plants occurring inland. Both the probability of flowering andof producing capsules increased with plant size. However, seed viability was low and did not differ across localities. Germination trialswere successful, but also yielded relatively low germination probabilities. In summary, our results revealed plant size-relatedvariation in T. landbeckii’s reproductive capacity. In spite of this variation, however, low seed viability supports previous findingsthat sexual reproduction scarcely contributes to recruitment in this population; hence propagation of this species may eventually benecessary to promote genetic diversity.

Effect of slope exposure on the structure and diversity of a submontane scrub in Northeast Mexico

Eduardo Alanís-Rodríguez — 2024-06-30

Slope exposure is one of the environmental factors that influences vegetation characteristics. Although there are studies on this aspect in various types of vegetation, up to now submontane shrublands have not been extensively studied. In this work, the effect of slope exposure on the structure and composition of plant species in a state park in northeastern Mexico where the dominant vegetation is submontane scrub was evaluated. Ten 10 x 10 m exposure sites were sampled: northeast, southwest and northwest. Total height (h), basal diameter (d_0.10) and crown diameter (k) were measured for each individual. Our hypotheses were: 1) the northwestern exposure community will have greater basal area, canopy cover, volume, absolute abundance, and specific richness due to higher humidity, 2) each slope will present dissimilarity in species composition. As results, nine families, 17 genera and 17 species of vascular plants were recorded. Fabaceae was the best represented family with six species. The species with the highest importance value index were the endemic shrub Neopringlea integrifolia in the northeast exposure (21.52 %) and the exotic tree Leucaena leucocephala in the southwest (16.17 %) and northwest (27.16 %) exposures. It is concluded that the plant community of the northwest exposure has a greater basal area, crown cover, volume, absolute abundance and specific richness. However, there was no real difference in the species composition of the three exposures.

Seed germination strategies of 10 species of native herbaceous plants of the sclerophyllous shrubland in central Chile

Javier A. Figueroa — 2024-06-30

The relative importance of light and the effect of cold for germination of 10 herbaceous plants native to the shrubland of central Chile was explored. The seeds of each species were assigned to: (1) seeds germinated for three months under white light, no cold was applied, (2) seeds germinated for three months under white light, cold stratification (5 °C) was applied for three months before being sown, (3) seeds germinated in darkness for 30 days, and (4) seeds germinated in light for 30 days. (1) and (2) sown at the same time. Similarly, (2) and (3). Both were compared with Student’s t tests. Five germination variables were evaluated with Principal Component Analysis (PCA). Five species achieved significantly higher germination under light than in darkness. Four species presented significantly higher germination in seeds exposed to cold. The first two dimensions of the PCA explained 79.36 % of the variance, with the first dimension explaining 44.72 %. The first dimension was associated with the light-dependent variable. The second was associated with the cold-dependent variable. The results show that the 10 herbs present some degree of light-dependent germination. However, cold dependence was of negative value for two species. Both variables are inversely correlated, supporting the hypothesis of two potential strategies: (1) associated with the variation of light in space and (2) associated with the variation of temperature in time.

Reproductive phenology of Pilgerodendron uviferum (D. Don) Florin on Chiloé Island, Chile

Nicole Galindo — 2024-06-30

Pilgerodendron uviferum is a conifer species of high ecological importance, which after several centuries of extensive burning and indiscriminate felling presents conservation problems. The lack of knowledge about critical aspects of their reproductive cycle represents currently an important gap to support forest restoration projects, particularly in optimal seed collection times and the possible interruption of pollination and/or seed dispersal mechanisms. In this work, we study the reproductive phenology of P. uviferum on Chiloé Island during three years, with the aim of identifying their reproductive stages and occurrence over time. The male and female reproductive structures of P. uviferum were quantified in each summer, autumn, winter and spring season, classifying them according to their state and phenophase. P. uviferum has a reproductive cycle limited to a ca. 1 year. In male and female trees, it is observed that more than 50 % of the branches present differentiation of the reproductive buds, of which more than 75 % manage to disperse the pollen and 80 % of the female cones are pollinated. However, seed dispersal is considerably low, being zero the first year. The reproductive success largely depends on female trees, since male trees showed a regular pattern of cone production. The reduction in viable seed harvest is one of the most important ecological problems in conifers and has implications for seed production for restoration programs.

Symbiotic and asymbiotic germination in vitro of Chloraea longipetala (Orchidaceae), an endemic orchid from Chile

Orlando Jeldes-Cajas — 2024-06-30

Chile has about 72 species of terrestrial orchids, most of them endemic. Some are threatened due to habitat loss, fires and herbivores damage and many have potential as ornamental plants or cut flowers. In vitro plant germination could be a key strategy for the long-term conservation and propagation of these species. In vitro asymbiotic and symbiotic, germination and subsequent embryo development in the orchid Chloraea longipetala were evaluated using five different culture media, aiming to provide efficient protocols for its propagation. For asymbiotic germination, we used water agar (AW), banana culture medium (CMB), tomato culture medium (CMT), oatmeal agar (OMA) and Malmgren terrestrial orchid medium (MM). For symbiotic germination, just AW and OMA were used. In addition, seed viability was estimated and reached 86.6 %. After four weeks, in all media except AW, the germination stage (embryo emerges from seed coat) was reached, for asymbiotic germination. However, there were no significant differences in the germination percentage among all five media, not exceeding 10 % in any treatment. After eight weeks, only seeds in MM reached the protocorm stage. On the other hand, symbiotic germination resulted in a significantly higher germination percentage (40 %), and embryos reached the rhizoid stage. For C. longipetala, unlike other Chilean species, the presence of orchidiod fungi seems to be necessary for successful and efficient germination and embryo development. This information is key for future propagation initiatives, for conservation, restoration or commercial applications as ornamental plants.