Sida Species Research Articles

Phylogenetic Relationships and Classification of the Sida Generic Alliance (Malvaceae) Based on nrDNA ITS Evidence

Phylogenetic relationships among members of the subtribe Abutilinae and particularly the taxa in the Sida generic alliance are currently poorly understood. The internal transcribed spacers of nuclear ribosomal DNA (ITS1 1 ITS2) from 58 species (51 new sequences) of Malvaceae were sequenced. The ITS data show that species from sects. Cordifoliae, Ellipticifoliae, Muticae, Sida, Spinosae ,a ndStenidae fall within a well-supported Sida core clade. This clade, which also includes the genus Dendrosida, groups species with a basic chromosome number of seven. Several species are placed outside of the Sida core, confirming preliminary suggestions of the paraphyly of this group based on morphological and cytogenetic evidence. Other sections, such as sect. Nelavagae, are monophyletic and sister to the Sida core, whereas sect. Malachroideae is placed outside of the Sida core in an unresolved position. Meximalva and Sidastrum as well as an Australian group of Sida species form a well-supported clade. Sida hookeriana and S. hermaphrodita are placed in a clade and associated with Sidasodes, removed from the Sida core, indicating a position much closer to subtribe Malvineae than previously suggested. Molecular evidence does not provide clear limits to the Sida generic alliance as currently circumscribed.

Differential Fluorescent Chromosome Banding of Four Sida spp. (Malvaceae).

Three Sida spp. viz. S. acuta, S. rhombifolia var. rhomboidea, S. cordata and a putative hybrid between S. acuta and S. rhombifolia var. rhomboidea were cytogenetically investigated to elucidate their characteristic karyotypes. S. acuta and S. rhombifolia var. rhomboidea possessed 2n=28 and 2n=14 chromosomes, respectively. In S. cordata, 2n=32 and in the putative hybrid, 2n=28 chromosomes were observed. The total length of 2n chromosome complements in S. acuta and S. rhombifolia var. rhomboidea were 55.6 μm, and 35.7 μm, respectively. In S. cordata, total length of 2n chromosome complement was 47.4 μm and in the putative hybrid, 96.7 μm. Except the putative hybrid, all species had only metacentric chromosomes. On the other hand, the putative hybrid had 6 sub-metacentric (6 sm) and 22 metacentric (22 m) chromosomes. Four CMA-positive bands were found in S. acuta, S. cordata and the putative hybrid, whereas, 2 such bands occurred in S. rhombifolia var. rhomboidea. These banded regions were DAPI-negative, indicating their absolute GC-rich nature. Both DAPI-positive (9) and negative (4) bands were found in S. cordata. An analysis of these data indicates that each Sida species possesses a distinct karyotype. The different 2n chromosome number, centromeric formula, length of total chromosome complements and fluorescent banding pattern unequivocally indicate a separate taxonomic rank of the putative hybrid.

Economic Yield Response of Peanut (Arachis hypogaea) to Postemergence Herbicides

Field experiments were conducted in 1988 and 1989 to evaluate timing of POST herbicide application in peanut for annual broadleaf weed control, peanut yield, and net returns. Bentazon tank-mixtures with either acifluorfen or paraquat controlled common lambsquarters, prickly sida, and morningglory species equally when applied either at ground-cracking (GC) or 2 wk after ground-cracking (2WGC). Paraquat controlled common lambsquarters least (32 to 33%). Bentazon plus acifluorfen plus BCH 81508S controlled 82% common lambsquarters at 2WGC compared with 66% control from bentazon plus acifluorfen plus a crop oil concentrate. Lactofen controlled 86% common lambsquarters when applied at GC compared to 34% at 2WGC. All applications applied at 4 wk after GC (4WGC) controlled essentially no annual broadleaf weeds. Higher yields and net returns were generally obtained with earlier herbicide applications. Bentazon tank-mixtures with acifluorfen provided equivalent peanut yields and net returns for GC and 2WGC applications.

Studies on medicinal plants of Sri Lanka. III. Pharmacologically important alkaloids of some sida species.

The major alkaloid of Sida acuta was shown to be cryptolepine which has antimicrobial activity against Proteus vulgaris. Thirty one samples of leaf, stem, root and seed of six Sida species collected from different localities in Sri Lanka were screened for the pharmacologically important alkaloids, cryptolepine, ephedrine, and vasicine. Medicinal applications of S. acuta and S. cordifolia have been related to dieir constituent alkaloids.