Received 28 February 2002, accepted in revised form 2 March 2002

There should be cogent reasons for wishing to replace natural seed with somatic or synthetic seed, especially in the Coniferophyta where orthodox seed that can survive in the desiccated state prevails. The nucleus of the artificial seed is the somatic embryo, and the cost of this type of seed will be related to efficiency of somatic embryo production and viability of the somatic seed. At present there are three major obstacles: the conversion frequencies of mature, desiccated somatic embryos to plantlets are low; responsive cell lines require cryostorage as they tend to lose their embryogenic potential rapidly; and survival and germination of encapsulated somatic embryos are low. Therefore, it is not anticipated that somatic seed will ever find use for on-site reforestation. Gymnosperms are outcrossing, and the most common method of mass propagation is via clonal seed-orchard production. In contrast to some species, somatic seed in the conifer is not needed for developing synthetic varieties or overcoming genetic barriers, such as autotetraploidy, but rather for allowing clones to be tested and then rapidly mass propagated, complementing seed-orchard production and use of rooted cuttings. Somatic seed remains a poor analogue of natural seed in terms of viability, handling and storage. More basic comparative biochemical and physiological research is needed to understand the differences in response between zygotic and somatic seed, so as to determine whether or not the somatic embryo is behaving like a recalcitrant seed and/or like an isolated zygotic embryo in vitro.

Received 3 November 2000, accepted in revised form 30 May 2001

A detailed account is given of the broad vegetation types of the Sekhukhuneland Centre of Plant Endemism. Phytosociological data from 415 sample plots were subjected to phytosociological classification using TWINSPAN. The resulting classification was further refined with table-sorting procedures based on the floristic-sociological approach to classification of vegetation. The analysis revealed six major vegetation types, interpreted as the Acacia tortilis-Dichrostachys cinerea Northern Dry Mixed Bushveld, the Kirkia wilmsii-Terminalia prunioides Closed Mountain Bushveld, the Combretum hereroense-Grewia vernicosa Open Mountain Bushveld, the Hippobromus pauciflorus-Rhoicissus tridentata Rock Outcrop Vegetation, the Themeda triandra-Senecio microglossus Cool Moist Grasslands and the Fuirena pubescens-Schoenoplectus corymbosus Wetland Vegetation. Each major vegetation type is described and its diagnostic species highlighted. The occurrence of rare and threatened plant species in each vegetation type is indicated.

Received 7 February 2001, accepted in revised form 4 June 2001

An investigation of mature seed structure in Guthriea capensis and ovule-to-seed development in Acharia tragodes indicate that the two species are herbaceous myrmecochores with similar adaptations for seed dispersal and germination. The development and structure of the modified seed tissues, namely a sarcotestal elaiosome, a fringe layer in the mesotesta, endotestal-exotegmic mechanical layers and a chalazal seed lid are described. Additional embryological similarities between the two taxa include, amongst others, sessile ovules, distally lobed outer integuments, zigzag micropyle canals formed by both integuments, bisporic Allium Type embryo sacs, suspensorless embryos belonging to the Penaea Variation of the Asterad Type, and small embryos in the mature seed. In Acharia intraseminal embryo growth occurs before radicle emergence, germination is epigeal and seedlings belong to the Macaranga Type.

Received 5 February 2001, accepted in revised form 6 June 2001

Levels of anti-inflammatory activity exhibited by Eucomis autumnalis autumnalis were affected by the environmental conditions during the period of winter dormancy. Bulbs stored at low temperatures (10°C) showed a limited period of time during which the anti-inflammatory activity of the bulb extracts was higher than that of the control. This effect was evident for a longer period in the leaves. Extracts prepared from E. autumnalis (subspecies autumnalis) bulbs, which were removed from the soil and stored at 8—10°C during the winter months, exhibited significantly higher COX-1 inhibitory activity than those extracts prepared from control bulbs maintained in the soil in a greenhouse (15—24°C) during winter, and from bulbs stored dry in paper bags (±18°C). A second harvest, performed on plants that had been returned to the soil after winter storage, was conducted half-way through the growing season. Higher COX-1 inhibitory activity was observed in the leaf extracts from the plants subjected to cold storage, than in the extracts from plants stored dry or in the greenhouse. No significant difference was observed at this stage between the activity of the bulb and root extracts from the different treatments. All extracts were prepared at a concentration of 250µg ml-1 for comparison.

Received 7 December 2000, accepted in revised form 12 June 2001

Seeds from only six species are known to germinate under anoxia of which Erythrina caffra Thunb. is the only dicot species found on dry land. It has been suggested in the past that seeds displaying a Pasteur effect are usually intolerant of anaerobic conditions. Although a Pasteur effect has been reported for Erythrina caffra seeds, the present study precludes this effect. In contrast, Pisum sativum seeds exhibit a strong Pasteur effect but are unable to germinate under anoxia. Anaerobic pre-treatment of Erythrina seeds enhanced the capacity of the oxidative pentose phosphate (OPP) pathway of axes. Glycolytic rates under aerobic and anaerobic conditions were similar. However, the amounts of glycolytic intermediates such as G-6-P, F-6-P, F-1,6-bisP, DHAP and GlycAld-3-P, in axes excised from air and N2 treated E. caffra seeds, differed sufficiently to indicate that glycolysis occurs faster in axes under aerobic than anaerobic conditions. The release of 14CO2 by axes and cotyledons from air-treated E. caffra seeds, after labelling with [U-14C]-glucose, was also much higher than that from N2-treated seeds. In P. sativum seeds, however, the opposite was true. Under anaerobic conditions it is expected that substrate level phosphorylation would be the main or only source of ATP production. Yet, increased activities were measured for phosphoenolpyruvate (PEP) phosphatase and phosphofructokinase (PFK), which bypass pyruvate kinase (PK) and PPi-dependent phosphofructokinase (PFP), respectively, in the glycolytic pathway. Collectively this data indicated that Erythrina caffra axes are able to utilise an alternative route for ATP production.

Received 19 April 2001, accepted in revised form 13 June 2001

The Western Cape geophyte Tritoniopsis parviflora (Iridaceae: Crocoideae) has been found to secrete floral oils as well as nectar. The oils are secreted from epithelial elaiophores over much of the proximal parts of the perianth. This is the first report of oil-secretion in the subfamily Crocoideae and the first record of oil-secretion in the Old World representatives of the Iridaceae. The species is pollinated by the large oil-collecting bee Rediviva gigas (Hymenoptera: Melittidae) and is part of a guild of yellow-flowered, often fragrant species that flower in late spring and early summer, usually only after a fire the previous season. Tritoniopsis parviflora will not self-pollinate and the provision of both oil and nectar may be a strategy for ensuring pollination in populations in areas where R. gigas is not present

Received 14 June 2001, accepted in revised form 25 July 2001

Salvia chamelaeagnea is an attractive, aromatic South African plant widely used for medicinal purposes. Explants can be easily induced to callus on Murashige and Skoog (MS) medium containing 2,4-D (1—2mg l-1) and induce shoots on the same medium containing 1mg l-1 BA. Transfer of the shoots on to MS medium containing NAA (0.5—2mg l-1) resulted in the formation of fast-growing roots. Plantlets can be readily transferred to soil. Chromatographic techniques indicated that extracts from both callus and leaves produced rosmarinic acid, with higher levels in the callus.

Received 26 March 2001, accepted in revised form 6 August 2001

Representative samples of the four South African species of Cissampelos were collected for morphological and anatomical studies. Leaves and rhizomes of all four species are used in traditional medicine and any morphological and anatomical differences could be useful in forensic studies. Rhizomes of Cissampelos are easily identifiable because of the sieve-like appearance in transverse section of all members of the Menispermaceae, but C. hirta and C. mucronata are difficult to distinguish from one another. These two species are anatomically similar and morphologically distinguishable only by leaf texture, colour and the presence of a geniculate pulvinus in C. hirta. Furthermore, tanniniferous idioblasts occur in these two species but not in C. capensis and C. torulosa. Leaf size is important to distinguish C. capensis from the other three species and leaf shape to distinguish C. torulosa from the rest. C. capensis differs from the others in a number of anatomical features.

Received 21 September 2000, accepted in revised form 15 August 2001

Nine seagrass species were identified around Inhaca as well as a more narrow form of Thalassodendron ciliatum (Forsk.) den Hartog occurring in rocky pools at the north east coast. Seagrasses were mapped and grouped in seven distinct community types (in order of areas covered): Thalassia hemprichii/Halodule wrightii, Zostera capensis, Thalassodendron ciliatum/Cymodocea serrulata, Thalassodendron ciliatum/seaweeds, Cymodocea rotundata/Halodule wrightii, Cymodocea serrulata and Halophila ovalis /Halodule wrightii; with the ninth species Syringodium isoetifolium occurring in three of these communities. A dichotomous identification key is presented. Seagrasses covered half of the whole intertidal area around Inhaca Island and diversity was also high at community level. Transects at macro and micro scales showed zonation of species which may be due to tidal gradients or topographic variation. Cluster analysis indicated ecological dissimilarities between co-dominant species. A decline of Zostera capensis has recently been seen outside the local village. Baseline studies like this are important for coastal zone management in developing countries, where large future changes in seagrass cover can be expected.

Received 30 October 2000, accepted in revised form 15 August 2001

A red alga that had previously been known from South Africa under the name ‘Erythroglossum sp.’ is recognised to represent a new species of Valeriemaya: V. seagriefii sp. nov. Collections of this alga occurring in the lower intertidal and subtidal habitats of rocky shores have been made from both the Eastern Cape and Western Cape Provinces. This represents the first report of the genus Valeriemaya from Africa. Previously, the genus, characterised by its typical apical organisation, monostromatic blades, an ill-defined midrib region, and the absence of microscopic nerves or veins, has been known with certainty only from eastern Australia. Valeriemaya seagriefii is delineated from the two previously known species of the genus by the overall size of the blades, the location of sporangial sori, the absence of gland cells, and blades which do not recurve towards the substratum to become attached and give rise to new blades. Valeriemaya seagrieffii has been collected from Glencairn, False Bay to Hluleka in the Eastern Cape Province.

Received 18 December 2000, accepted in revised form 15 August 2001

The objective of this work was to evaluate the differences in distribution of photoassimilates between a sample of a wild population and a domesticated variant of common bean, by comparing the yield components, harvest index, leaf area efficiency and seed filling rate, when grown under greenhouse conditions. Significant positive correlations were observed in the wild common bean for seed yield and seed number per plant and seed number per pod. In contrast, in the domesticated variant there was a positive correlation between seed number and pod number per plant, stem dry weight and number of nodes. Seed size in the domesticated variant was associated positively with yield. The biomass per plant accumulated in stems, leaves and pod walls was statistically similar between the wild and the domesticated variant, but a different distribution of assimilates caused a difference in the size and number of these structures. However, total biomass per plant was higher in the domesticated variant due to high seed biomass. The greater efficiency of seed production of the domesticated bean was associated with a longer life span of the leaves, a higher harvest index and reduced competition between vegetative and reproductive structures. These results support the hypothesis that domestication increased the efficiency in partitioning of photoassimilates toward seeds in the common bean.

Received 24 July 2001, accepted in revised form 21 August 2001

The flowers of Crinum variabile (Amaryllidaceae) exhibit the characteristics of sphingophily, including a long-tubed, pale-coloured perianth that expands more fully at night, a strong sweet fragrance dominated by the acyclic terpenoid alcohol, linalool and abundant nectar. The hawkmoth Hyles lineata (Sphingidae) was recorded as a pollinator of the species. A total of 22 species of southern African Amaryllidaceae in the genera Crinum, Cyrtanthus and Pancratium conform to the syndrome of sphingophily. Sphingophilous species of Amaryllidaceae are widely distributed across southern Africa, most commonly in savannah and grassland but are almost absent from the winter-rainfall parts of the region. The uneven distribution of these species in southern Africa correlates with a shortage of appropriate larval food plants in the Cape Region.

Received 23 April 2001, accepted in revised form 11 June 2001

A new autoecious, macrocyclic, species of rust fungus, Uromyces strumariae, is described from Strumaria gemmata (Amaryllidaceae). The new species is readily distinguished from U. badius, the only other Uromyces species known to attack members of the Amaryllidaceae in South Africa, by its telia which develop separately from the uredinia (the uredinia become telia in U. badius), and the presence of paraphyses in the telia (absent in U. badius). It is currently known only from De Hoop Nature Reserve at the western most edge of its host’s distribution, in the winter rainfall region of South Africa. Furthermore, U. badius has also recently been collected on H. pubescens L.f. subsp. pubescens, representing a new host record.

Received 25 January 2001, accepted in revised form 13 June 2001

The fruits of Kigelia africana (Lam.) Benth. are a popular source of traditional medicine throughout Africa. The stembark has been widely analysed for pharmacological activity, yet knowledge of the fruits is limited, despite more extensive use in traditional remedies. Crude extracts of stembark and fruits were prepared with distilled water, ethanol or ethyl acetate. In the microtitre plate bioassay, stembark and fruit extracts showed similar antibacterial activity against Gram-negative and Gram-positive bacteria. A mixture of three fatty acids exhibiting antibacterial effects was isolated from the ethyl acetate extract of the fruits using bioassay-guided fractionation. Palmitic acid, already known to possess antibacterial activity, was the major compound in this mixture. These results confirm antibacterial activity of K. africana fruits and stembark, and support the traditional use of the plant in therapy of bacterial infections.

Received 29 March 2001, accepted in revised form 24 July 2001

Continuous culture systems were successfully established for Scilla kraussii and Scilla dracomontana. The efficiency of the systems was strongly influenced by the combinations of plant growth regulators. The shoots were successfully rooted and then acclimatised. Continuous culture systems, therefore, can be used to produce large quantities of plantlets, particularly where conventional propagation is limited by the small size of the bulb and the limited number of seed produced as for S. dracomontana. This would serve both conservation and commercial interests.

Received 23 March 2001, accepted revised form 24 July 2001

Seed germination is poor in species of the nut-fruited Restionaceae. Investigations of seed morphology and development, seed collection and sorting, and seed viability were conducted in species of Cannomois Desv., Hypodiscus Nees and Willdenowia Thunb. to supplement existing knowledge, and to determine whether poor seed quality resulted in the poor seed germination identified in previous studies. Suitability of collection methods and the effectiveness of sorting techniques were evaluated using x-radiography. Shaking and ground collection methods yielded consistently higher proportions of full seed than extracting seed from cut shoots. However in species with bony bracts and few seeds per plant, the cutting method was more suitable. Floating was a better seed sorting technique than weighing for separating full from incompletely filled seeds. Seed viability in seed collections that had been sorted to contain only fully developed seeds was assessed using tetrazolium salts. Viability was generally high (mostly >80%), suggesting that poor germination in studies with well-sorted seeds is likely to be due to seed dormancy.

Received 23 March 2001, accepted in revised form 24 August 2001

The morphology of plastid starch grains from nonarticulated laticifers was examined in Anthostema aubryanum Baill. and Euphorbia esula L. by light and scanning electron microscopy. Starch grains from E. esula are elongated and somewhat wider at the mid-region than toward the ends, and result from bipolar deposition of starch on an initially small round grain during grain ontogeny. In A. aubryanum starch grains develop into biconcave disks. Starch deposition occurs primarily in a peripheral ring upon a small grain initial and continues to increase in thickness at the periphery during ontogeny to form the biconcave disk. These contrasting patterns of development for laticifer starch grains from small round grains, rather than modification of complex grains, supports an interpretation that their modification in Anthostema and Euphorbia represents separate evolutionary directions.

Received 11 June 2001, accepted in revised form 21 September 2001

Somatic and zygotic embryos of Pinus patula Scheide et Deppe. were encapsulated in 2.2% sodium alginate to examine the potential of producing artificial seeds. The alginate beads were supplemented with sucrose, maltose and activated charcoal. Somatic embryos encapsulated in alginate beads supplemented with both sucrose and charcoal germinated from the alginate beads after 14 days, and could be stored for 20 days with a 30% decrease in the percentage germination.

1999 AA Balkema, PO Box 1675, 3000 BR, Rotterdam, Netherlands, e-mail [email protected]

VII plus 120 pages, 80 colour photographs, 15 line drawings, 18 maps

Case bound with dust jacket: ISBN 90 5410 485 6; Price: Euro 45

AE Orchard and AJG Wilson (Editors)

2001 CSIRO Publishing, PO Box 1139, Collingwood, Vic 3066, Australia, e-mail: [email protected]

Volume 11A: 673 pages, 32 colour plates, 3 black and white colour plates, 85 line drawings, 511 distribution maps, includes the keys to the Mimosaceae and to the genus Acacia in Australia

Volume 11B: 536 pages, 64 colour plates, 94 line drawings, 584 distribution maps

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WATTLE: Acacias of Australia CD-ROM

AE Orchard and AJG Wilson (Editors)

2001. CSIRO Publishing, PO Box 1139, Collingwood, Vic 3066, Australia, e-mail: [email protected] 

CD-ROM and 24 page manual, ISBN 0643066063, Price: A$110.00