J. C. Coetzee

The genus Calvatia ('Gasteromycetes', Lycoperdaceae): a review of its ethnomycology and biotechnological potential.

Several members of the fungal puffball genus Calvatia Fr. have found widespread use amongst various cultures world-wide, especially as sources of food and/or traditional medicine. Hitherto the biotechnological potential of only a handful of Calvatia species, namely C. cyathiformis, C. craniiformis, C. excipuliformis, C. gigantea and C. utriformis has been investigated. However, despite promising results, information regarding the biotechnological potential of the rest of the genus, in particular the African species, is still completely lacking. In the hope that it might stimulate interest and further research on this topic, the current paper provides a brief overview of the literature pertaining to the importance of Calvatia to man in terms of its pathogenicity, its ecology and role as bioindicator, its food and nutritional value and also its potential as biotechnological tool in the pharmaceutical and other industries.

A Study of Oxygenation Techniques and the Chlorophyll Responses of Pelargonium tomentosum Grown in Deep Water Culture Hydroponics

Pelargonium tomentosum Jacq.; the peppermint-scented pelargonium, is an herbaceous groundcover indigenous to the Western Cape of South Africa. Volatile oils are produced by this plant, which are used in the fragrance industry. Studies on other Pelargonium species have shown chlorophyll content may affect the yield of essential oils. This study was carried out to investigate the viability of growing P. tomentosum in deep water culture (DWC) hydroponics and how best to aerate/oxygenate the nutrient solution to increase the chlorophyll content within leaves. The experiment was conducted over a period of 74 days, 16 different methods of oxygenation were applied to 9 replicates. The control had passive aeration; the treatments were made up of air-pumps, vortex oxygenators, and the application of hydrogen peroxide at various frequency intervals; these were combined with each other and run as separate oxygenation methods. The measurement of the chlorophyll content of plant leaves has been established to be an accurate way of establishing vigor, health, and levels of stress. It was found that the combination of high-frequency application (every third day) of hydrogen peroxide, vortex oxygenation, and air-pump injection (both operational for 24 hours/day) which formed treatment 11 (APVHa), yielded the highest production of chlorophyll within all the replicates differing significantly (P £ 0.001) from the control and other treatments. Chlorophyll is vital for the process of photosynthesis to occur in both higher and lower plants (Konica Minolta, 2015; Stern et al., 2008) AU1 . Chlorophyll is an accumulation point for increased levels of nitrogen in plants, observation of the chlorophyll content within a leaf can be indicative of a plant’s ability to take up nitrogen, the development of chloroplasts, and thus photosynthetic capability. Measurement of chlorophyll content can provide information regarding the overall health of a plant (Ling et al., 2011; Marsh, 2016). Chlorophyll Fluorescence Light energy which is not absorbed by leaves to drive photosynthesis dissipates as heat or is reemitted as fluorescence (Maxwell and Johnson, 2000). Due to the different wavelengths at which light is reemitted as fluorescence to those which are absorbed by a leaf (described by the Kautsky effect), the level of photosynthesis (photochemistry) can be observed and the content of chlorophyll within a leaf ascertained (Maxwell and Johnson, 2000). Not only has observation of chlorophyll within plants provided researchers insight into the stress levels experienced in certain environments but also into quality of water used for irrigation and the effects of fertilizer application (Schlemmer et al., 2005; YSI, 2015). The proliferation of easy-to-use chlorophyll fluorometers over the decades preceding this study has made chlorophyll fluorescence a widely investigated parameter in scientific botanical research in both laboratory and field studies (Ling et al., 2011; Manetas et al., 1998; Maxwell and Johnson, 2000; van Kooten and Snel, 1990). The Role of Oxygen (O2) in Plant Growth O2 plays a vital role in plant metabolic processes (Zheng et al., 2007); respiration requires oxygen to be carried out effectively. It can be taken up through the stomata within the leaves or via the root system (Douglas, 1970). In land plants, O2 deficiency has a rapid deleterious effect on the ability of roots to absorb water and other essential compounds (Urrestarazu and Mazuela, 2005). Although glycolysis does not depend solely on the presence of O2 (Salisbury and Ross, 1985); when there is an absence of O2, the resultant pyruvate and nicotinamide adenine dinucleotide will accumulate resulting in anaerobic respiration. Oxygenation in Hydroponics Plant growth has been shown to increase when irrigated with additional dissolved oxygen (DO) in the solution (Soffer et al., 1990), therefore, in hydroponics it is important that oxygen is dissolved in the solution around the roots of plants. The level of O2 able to be held within the nutrient solution is affected by factors such as water temperature, air pressure, salt content, and purity (Ben-Yaakov and Ben-Asher, 1982; Kepenyes and V aradi, 2015; Morimoto et al., 1989) AU2 . O2 injection at low pressures using air compressors or pumps into the growing medium has been shown to have some positive trends even in field-grown crops (Chen et al., 2011). There are several established methods of dissolving O2 into hydroponic nutrient solution; these include the formation of droplets through spraying the solution at pressure, creating turbulence or agitation and by gaseous injection with air-pumps (Bonachela et al., 2005; Schr€oder and Lieth, 2002). Venturi oxygenators, surface agitators, paddles, and counter-flow column gas recyclers are methods mentioned by Kepenyes and V aradi (2015). The size of the bubbles of atmospheric gas which enter the nutrient solution affects plant development; root growth has been shown to be enhanced by the application of microbubbles (50 mm and smaller) compared with macrobubbles which are larger than 50 mm (Park and Kurata, 2009). Gaseous bubbles in the nutrient solution contain O2; however, this must be dissolved for submerged plant roots to use it (Bonachela et al., 2005). Air injection by using air-pumps with dispersers has become the conventional method for aerating the solution in hydroponics. These devices have shown beneficial effects on plant growth in hydroponics (Tesi et al., 2003) AU3 . Although there are few published findings of oxygenating water by means of vortices, W ojtowicz et al. (2013) found that atomization of water by vortex flow regulators used in waste and storm water management schemes increased DO levels. The effect of a venturi on fluid flow is a decrease in pressure and an increase in velocity, this can facilitate the formation of a visible spinning depression in the fluid (described as a vortex) where air or atmosphere is drawn toward the constriction in the flow apparatus due to the pressure differential. The uniform and predictable mixing of fluids (gas and liquid) created by venturi and the associated vortex formation is used by carburetors within internal combustion engines (Earls, 1997) to ensure efficient fuel/air mixing. Oxygenation of the solution can also be achieved with the addition of hydrogen peroxide (H2O2) and is commonly applied in hydroponic plant cultivation (Kessler, 2015). H2O2 is an unstable compound in the molecular sense, when the substance breaks down, one molecule of water is released as well as one highly reactive molecule of oxygen (O–) which either binds to another O– and results in a stable molecule of oxygen (Fredrickson, 2014), or reacts with an organic compound (usually degrading the said compound). The warmer the water gets (above 2 C), the amount of O2 which can be dissolved in the solution is reduced; the Corresponding author. E-mail: joshuabonesbutcher@ gmail.com. HORTSCIENCE VOL. 52(7) JULY 2017 1 CROP PRODUCTION

Calvatia Fr. (Fungi, Lycoperdaceae) in suider-Afrika : 50 jaar na Bottomley : referaatopsomming

This paper was initially delivered at the Annual Congress of the Biological Sciences Division of the South African Academy for Science and Art, ARC-Plant Protection Research Institute, Roodeplaat, Pretoria, South Africa on 01 October 2010.

Calvatia Fr. (Fungi, Lycoperdaceae) in southern Africa: 50 Years after Bottomley

This paper was initially delivered at the Annual Congress of the Biological Sciences Division of the South African Academy for Science and Art, ARC-Plant Protection Research Institute, Roodeplaat, Pretoria, South Africa on 01 October 2010.

Calvatia Fr. (Fungi, Lycoperdaceae) in suider-Afrika : 50 jaar na Bottomley

This paper was initially delivered at the Annual Congress of the Biological Sciences Division of the South African Academy for Science and Art, ARC-Plant Protection Research Institute, Roodeplaat, Pretoria, South Africa on 01 October 2010.

Nomenclatural and taxonomic notes on Calvatia (Lycoperdaceae) and associated genera

Various nomenclatural aspects pertaining to author citations, orthography and the validity of names in the genus Calvatia, and, in one instance, Bovista, are discussed. The name Calbovista subsculpta var. fumosa is validated and the biogeographic status of Calvatia gigantea in southern Africa is discussed. The name Calvatiella lioui is lectotypified.