Search

The study was intended to investigate the presence of phytoconstituents in the bulbs of Narcicuss tazetta, flowers of the plant Nymphaea mexicana, and roots of Indigofera heterantha. The present study provides evidence that methanolic extracts of Narcicuss tazetta, Nymphaea mexicana and Indigofera heterantha contain important compounds with marked bioactivity. Maximum phenolic content was observed in Nymphaea mexicana and maximum flavonoid content was observed in extract of Indigofera heterantha. Keywords: Phytoconstituents, Antioxidant, Nymphaea mexicana, Narcicuss tazetta, Indigofera heterantha

Nymphaea mexicana Zuccarini (Nympheaceae) (Mexican waterlily) is a rooted floating-leaved aquatic plant native to southern USA and Mexico that has become a problematic invasive alien plant in South Africa. Biological control is considered a desirable management strategy for the plant in South Africa. A good understanding of the genetic structure of invasive populations has been useful in other biological control programmes because taxonomic uncertainty about the target plant can result in natural enemies that are not adapted to the invasive populations being considered as potential agents. For N. mexicana, hybrids exist in the wild and horticultural trade, but identification is difficult, so understanding the genetic structure of populations is required to ensure that potential agents are collected off plants similar to invasive populations in South Africa. ISSR (inter-simple sequence repeats) analysis was used to determine whether invasive N. mexicana populations from South Africa were genetically similar to native range populations from USA or whether they were hybrids. Results from these analyses were matched with the morphotypes of each population based on petal colour, shape, and size. The genotypes suggested by the ISSR analyses corroborated the presence of both hybrid and pure forms of N. mexicana in South Africa. Populations of N. mexicana in the invaded range that are genetically similar to native range populations are more likely to be suitable for biological control, while other populations are likely to be hybrids formed by crossing of parents from the native range or within the horticultural trade, which may present difficulties for management using biocontrol.

Nymphaea mexicana Zuccarini (Nymphaeaceae) (Mexican waterlily) is an emergent floating-leaved aquatic plant from the southeastern USA that is invasive in South Africa. In invaded waterbodies this plant restricts water movement, increases siltation, decreases recreational activities, and can deplete water oxygen levels, which in turn negatively impacts aquatic fauna. Currently there are no chemical, mechanical, or biological control programs in place for N. mexicana in South Africa, but the sustainability of biological control makes this the most desirable option. Field surveys for potential biological control agents were conducted in the native range of N. mexicana in Florida, Louisiana, and Texas from Aug to Oct 2018. Leaves, stems, flowers, and roots of N. mexicana were searched for insect herbivores by hand and using Berlese funnels. Insects were prioritized for use as biological control agents by considering the extent and type of feeding damage, field host range, and incidence (percentage of sites in which each species was found). In total, 15 confirmed species were found feeding on N. mexicana, and some taxa were identified only to family level. Incidence coverage estimator mean, MMRuns, Chao 2 mean, and Chao 2 upper 95% CI species accumulation estimators predicted that between 2 and 5 species were missed during the surveys. Based on field observations, Bagous americanus LeConte (Coleoptera: Curculionidae), and Megamelus toddi Beamer (Hemiptera: Delphacidae) were prioritized. Host specificity trials will be conducted to determine whether these insects may be used as biological control agents of N. mexicana.

Nymphaea odorata, Nymphaeaceae, is the most widely distributed water-lily in North America. Disagreement exists on whether this morphologically variable species should be split into two species, N. odorata and N. tuberosa, or treated as one species with two subspecies. Morphological characters and markers from the inter-simple sequence repeats (ISSRs) were examined to assess taxonomic status and elucidate patterns of genetic variation among populations. This study provides evidence against treatment of N. tuberosa at species rank. The principal component analysis of 26 vegetative characters underscores immense variability, but does partially segregate populations of subsp. odorata and subsp. tuberosa. Based on analysis of variance, a new set of morphological characters is proposed to distinguish the two subspecies: mean leaf blade length-to-width ratio, petiole striping, and lobe apex shape. Results from ISSRs show high polymorphism within and among populations. Genetic variation was found largely within geographical regions (89%) rather than among regions. Principal coordinate (PCOA) analyses and minimum spanning tree (MST) analyses based on ISSRs clearly distinguished Nymphaea mexicana and N. odorata. Within N. odorata, samples of subsp. odorata appear to be a distinct entity, whereas samples largely but not completely separated from samples of subsp. tuberosa. PCOA and MST showed linkage between most samples of subsp. odorata whereas this was less evident in UPGMA.

Sequence data from the nuclear internal transcribed spacer (ITS) and the plastid trnL-trnF regions were used to assess relationships among populations of N. odorata across its North American range, and to evaluate whether subsp. odorata and subsp. tuberosa form distinct taxonomic units. Nymphaea mexicana was included because of suspected hybridization with N. odorata. The trnL-trnF region provided a single informative site in N. odorata. In contrast, the ITS region was more variable. Phylogenetic analysis of ITS data supports the monophyly of the two species. Within N. odorata, two clades were resolved largely representing subsp. odorata and subsp. tuberosa, although a few individuals appeared outside the respective clades. Polymorphic sites were detected in ITS, indicating possible hybridization between the subspecies. The geographic location of these hybrids suggests a possible hybrid zone. Overall, molecular evidence supports the segregation of subsp. odorata and subsp. tuberosa, with limited gene flow between them.

Mature pollen grains ofNymphaea mexicana have a verrucate proximal surface, a psilate distal surface and an anazonasulculus (encircling-sulcate aperture). The developmental events of microspores and tapetal cells were observed with TEM and SEM. Radially oriented substructural elements are seen in the microspore surface coating ofNymphaea mexicana from the early tetrad stage through the whole exine development. These elements, being the structural units of the microspore surface matrix (glycocalyx), are associated with sporopollenin precursor accumulation. In young free microspores, radially oriented elements are observed at both proximal and distal poles as a “palisade” between the endexine and plasmalemma.—Several points are discussed: (1) the initial and mature forms of exine substructure elements; (2) the significance of exine substructure for realisation of morphogenetic processes; (3) the ways by which verrucate and psilate sculpture patterns are developed.

Nymphaea mexicana Zucc. is an aquatic plant species which belongs to the family Nymphaea and is commonly known as the yellow water lily. The aim of this work was to study the in vitro anti-inflammatory effects of phenolic compounds isolated from the flowers of Nymphaea mexicana Zucc. Seven phenolic compounds including vanillic acid (1), 4-methoxy-3,5-dihydroxybenzoic acid (2), (2R,3R)-3,7-dihydroxyflavanone (3), naringenin (4), kaempferol 3-O-(3-O-acetyl-α-L-rhamnopyranoside) (5), kaempferol 3-O-(2-O-acetyl-α-L-rhamnopyranoside) (6), and quercetin 3-(3′′-acetylrhamnoside) (7) were isolated from the flowers of Nymphaea mexicana Zucc. These results revealed that compound 4 has the most prominent inhibitory effect on the LPS-stimulated nitric oxide (NO), monocyte chemotactic protein-1 (MCP-1), and tumor necrosis factor-alpha (TNF-α) production in RAW 264.7 macrophages. In addition, compound 4 also inhibited LPS-mediated induction of protein expressions of inducible nitric oxide synthase (iNOS), cyclooxygenase 2 (COX-2), and phospho-ERK in RAW 264.7 macrophages. Thus, compound 4 from the flowers of Nymphaea mexicana Zucc. may provide a potential therapeutic approach for inflammation-associated disorders.

Surface waxes from eight species of aquatic angiosperms were extracted. Four species have submerged leaves ( Cabomba caroliniana Gray, Egeria densa Planch., Eriocaulon aquatile Koern. and Mayaca fluviatilis Aubl.), three have emergent leaves ( Eichhornia crassipes (Mart.) Solms, Myriophyllum aquaticum (Vell.) Verdc. and Pistia stratiotes L.) and one has floating leaves ( Nymphaea mexicana Zucc.). In all cases the yield of waxes was low and ranged among the species from 1.1 to 16.1 μg cm −2 . The alkanes were separated from the waxes through column chromatography and identified by means of gas chromatography. The carbon chains of the alkanes of the species with submerged leaves are, on average, shorter than those of the species with air-exposed leaves. The distribution of alkanes of the latter species is similar to the alkane profiles of foliar waxes of terrestrial plants.

Nymphaea mexicana Zuccarini, a species from southern USA and Mexico, is reported for the first time from the Iberian Peninsula. A brief description of the site and taxonomical characteristics are given.

The floral biology of Nymphaea mexicana Zuccarini has been investigated. Anthesis is diurnal with flowers opening and closing for two consecutive days. Flowers on the first day of anthesis are functionally female with the stigmatic papillae secreting a small quantity of fluid. Total dissolved solids of the stigmatic fluid range from 3 to 4%; glucose and fructose are in equal concentrations and a large number of free amino acids are present. Flowers are primarily visited by Dialictus bees, flies and beetles. These insects typically land on the wet stigmatic surface where the secretion loosens pollen from the insects' body. On the second day of anthesis, the anthers dehisce and the stigmatic fluid disappears. This latter phenomenon is associated with a loss of stigmatic receptivity. Since protogyny is complete, flowers are obligatorily entomophilous. After anthesis, the flower closes and submerges. The perianth and androecium abscise and decompose as the fruit matures. The fruit yields large trichomic seeds. The phylogenetic position of N. mexicana within the genus is discussed.

The yellow waterlily, Nymphaea mexicana Zuccarini, is reported for New Zealand for the first time. This species, previously identified in the New Zealand literature as Nymphaea alba L., is well est...

The development of labelled flowers of three species of Nymphaeaceae grown in outdoor concrete tanks situated near the university area, was followed by means of daily observations. The duration of the prefloral, floral s.s. and postfloral stages is shown in table 1.