Topic
Sparaxis
About: Sparaxis is a research topic. Over the lifetime, 20 publications have been published within this topic receiving 264 citations. The topic is also known as: Harlequin flowers..
Papers
TL;DR: Differences in responses of the twelve species tend to cut across the three families and no simple relation is evident between the natural rate of vegetative increase and the in vitro behaviour.
Abstract: In vitro responses of twelve species of bulbs and corms were compared. Plantlets could be induced directly without intervening callus on stem tissue in nine species, on ovary tissue in five species, and on leaf tissue in four species. In Gladiolus, Hyacinthus, Muscari, Ornithogalum, and Scilla plantlets were formed without growth factors added to the Murashige and Skoog medium. In Hippeastrum, Schizostylis, Sparaxis, and Ipheion auxin was required. No plantlets could be induced directly on expiants of growing tissue of Freesia, Tulipa, or Narcissus. Adventitious plantlets could be induced on pieces of bulb or corm from ten species but such material was difficult to free from contamination. Callus was obtained from all species except Tulipa and Hippeastrum. Plantlets could be regenerated from callus except that of Gladiolus, Sparaxis, and Schizostylis. Differences in responses of the twelve species tend to cut across the three families and no simple relation is evident between the natural rate of vegetative increase and the in vitro behaviour.
97 citations
1 Jan 2000
TL;DR: Une analyse phylogenetique suggere that la pollinisation par des Anthophorinae attires par le nectar est le syndrome ancestral dans le genre Sparaxis.
37 citations
TL;DR: The dynamic patterns for the majority of the resources revealed high allocation when metabolic activity was also highest, seen as an advantage to these plants that grow in a seasonal environment where soils are of low nutrient status.
30 citations
Journal Article•
TL;DR: In this paper, a phylogenetic analysis of the systemes de pollinisation in the genus Sparaxis has been presented, and it has been shown that the pollinization par des Anthophorinae attires par le nectar is le syndrome ancestral dans le genre Sparopus.
Abstract: Des observations de terrain, des dissections florales, des analyses du nectar, et l'examen du pollen preleve sur des insectes visiteurs captures dans les fleurs de 13 des 15 especes de Sparaxis, montrent que les systemes de pollinisation sont particulierement diversifies au sein de ce petit genre d'Iridaceae endemique d'Afrique australe. Trois systemes de pollinisation, se chevauchant, impliquant des vecteurs polliniques appartenant a trois ordres d'insectes (Coleopteres, Dipteres et Hymenopteres), peuvent etre reconnus chez Sparaxis. Quatre especes (S. auriculata, S. caryophyllacea, S. variegata et S. villosa possedent des fleurs zygomorphes, bilabiees (de type « gosier ») dont les etamines sont appliquees contre un tepale dorsal erige ou encapuchonne; ces especes sont pollinisees essentiellement par des abeilles (Anthophorinae: Apidae) pour lesquelles le nectar est le principal attrait. Sparaxis metelerkampiae, a fleurs pourpre-fonce a long tube perianthaire, appartient a un ensemble local d'especes dont les membres possedent des fleurs de couleur semblable pollinisees par une mouche a longue trompe, Prosoeca peringueyi (Nemestrinidae). Sparaxis parviflora, aux fleurs minuscules bilabiees et odorantes, a antheres apparentes, est pollinise par des abeilles,melliferes autochtones, attirees par le pollen et le nectar. Les autres especes possedent des fleurs a perianthe actinomorphe et a tube floral etroit qui contient des quantites infimes de nectar; il s'agit d'especes non specialisees, visitees par un large eventail d'insectes dont des Scarabees (Hoppliinae), des Tabanidae a trompe courte et parfois des abeilles collectrices de pollen (chez S. bulbifera et S. fragrans). Une analyse phylogenetique suggere que la pollinisation par des Anthophorinae attires par le nectar est le syndrome ancestral dans le genre Sparaxis. Au cours de l'evolution, il y a eu, au moins une fois, changement du systeme de pollinisation impliquant des mouches a longue trompe puis, dans un clade une evolution vers des fleurs de plus en plus actinomorphes, liee au developpement d'un systeme specialise limite aux Tabanidae et aux Hopliinae a partir d'un systeme plus general impliquant des abeilles appartenant a diverses familles.
29 citations
Journal Article•
TL;DR: Application of titanium in the concentration of 0.04% increases the total yield of corms by 20% on average and the commercial yield by 7% and improved yield structure of c Corms of the first selection, respectively.
Abstract: The field study was carried out between 2000 and 2003. The plants of Sparaxis tricolor were sprayed twice prior to flowering with a fertilizer called titanium (0.8% Ti) in three concentrations: 0.02, 0.04 and 0.08%. Application of titanium in the concentration of 0.04% increases the total yield of corms by 20% on average and the commercial yield by 7%. Spraying the plants with titanium in the concentration of 0.02% increased the share of corms with > 5cm circumference in total yield and improved yield structure of corms of the first selection. A higher concentration of the preparation (0.08%) had unfa- vorable effect on the commercial yield of corms. In 2001 titanium applied in the concen- tration of 0.02% increased the nitrogen content in offspring corms and decreased content of other macro-elements. In 2003 offspring corms of plants treated with titanium in the concentration of 0.02-0.04% had more dry weight, N, P, K, Ca, Mg and Na.
14 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2013 | 1 |
| 2009 | 2 |
| 2008 | 1 |
| 2006 | 1 |
| 2005 | 1 |
| 2000 | 2 |