The genus Ipomoea (Convolvulaceae) in the Mata da Pimenteira State Park, semiarid region of Brazil

The Mata da Pimenteira State Park (MPSP) is an important remnant of caatinga vegetation in the semiarid region of Pernambuco state, Brazil. The park holds great biodiversity, but relatively few taxonomic studies have been undertaken in the area. We present a taxonomic study of Ipomoea in the MPSP based on field observations and collections deposited in the Herbarium of the Semiarid of Brazil - UAST / UFRPE (HESBRA). The species were identified based on the specialized literature, comparisons with type images available online, and protologues. Fourteen species of Ipomoea were identified - more than three times the previously known number. Two Ipomoea species recorded in the MPSP are endemic to Brazil (I. bahiensis and I. brasiliana), three others are exclusive to the Caatinga domain (I. marcellia, I. rosea, and I. tenera), and the remaining are widely distributed in South America. The habit, type and shape of leaf blade and sepals, corolla size and shapes, and presence or absence of subapical rostrum on the external sepals were the most relevant distinctive characteristics. An identification key, descriptions, comments on distribution and diagnostic characteristics, and phenological data of the species are presented.

Ipomoea lanifolia sp. nov. (Convolvulaceae), a new species endemic to the Ibiapaba plateau in northeastern Brazil

A new species of Ipomoea, thus far endemic to Caatinga domain, is described. The species occurs in a “carrasco” physiognomy - a shrubby vegetation on sandy soils characterized by the presence of cacti and bromeliads. The new species can be recognized by a combination of morphological characters, including a leaf blade with a lanate abaxial surface with long hairs, and sepals lanceolate, acuminate, tomentose, and smooth. A complete description, diagnosis, an identification key for Ipomoea species from the Ibiapaba plateau, illustrations, conservation assessments, a distribution map, and taxonomic comments are provided.

Detection of swainsonine and calystegines in Convolvulaceae species from the semiarid region of Pernambuco

ABSTRACT: Numerous plant species worldwide including some Ipomoea (Convolvulaceae) and Sida (Malvaceae) species in Brazil cause lysosomal storage disease in herbivores and are known to contain swainsonine and calystegines as the main toxic compounds. The aim of this work was to determine swainsonine and calystegines concentrations in species of Convolvulaceae from the semiarid region of Pernambuco. Seven municipalities in the Moxotó region were visited and nine species were collected and screened for the presence of swainsonine and calystegines using an HPLC-APCI-MS method. The presence and concentration of these alkaloids within the same and in different species were very variable. Seven species are newly reported here containing swainsonine and/or calystegines. Ipomoea subincana contained just swainsonine. Ipomoea megapotamica, I. rosea and Jacquemontia corymbulosa contained swainsonine and calystegines. Ipomoea sericosepala, I. brasiliana, I. nil, I. bahiensis and I. incarnata contained just calystegines. The discovery of six Ipomoea species and one Jacquemontia species containing toxic polyhydroxy alkaloids reinforces the importance of this group of poisonous plants to ruminants and horses in the semiarid region of Pernambuco. Epidemiological surveys should be conducted to investigate the occurrence of lysosomal storage disease associated to these new species.

Evolution of Natural Resistance to Glyphosate in Morning Glory Populations

ABSTRACT Tolerance, also referred to as natural resistance, is a feature that exists in the plant even before herbicide application in an area. I. grandifolia, I. indivisa and I. purpurea are among the tolerant species most commonly found over fields in southern Brazil. We hypothesized that the intensive use of glyphosate results in increasing levels of tolerance to glyphosate, and in pronounced response variability in populations of the same Ipomoea species. This study aimed at identifying tolerance variations to glyphosate among I. grandifolia, I.indivisa and I. purpurea morning glory species and among populations of these species. In crops over Paraná and Santa Catarina states (Brazil) 31 biotypes were collected (20I. grandifolia, 7I.indivisa and 4I. purpurea), on which were applied 0, 216, 432, 864, 1,296, 1,728 and 2,160 g a.e. ha-1 of glyphosate and the dose required to reduce 50% of dry matter (GR50) was determined. Biotypes of all tested Ipomoea species showed variability of glyphosate tolerance. Tolerance factors had greater amplitude among biotypes of I. gradifolia and I. indivisa species (between 1.7 and 33.6 and between 3.3 and 34.2, respectively) than in I. purpurea (between 3.7 and 4.9). Especially within I. gradifolia e I. indivisa species, some biotypes required a much higher dose than the recommended one to control the wild biotype, indicating progress in the level of glyphosate tolerance; this proves the initial hypothesis of this work.