Hydroponic culture of Gladiolus tristis: Application of paclobutrazol for flowering and height control

Gladiolus tristis (ever-flowering gladiolus) was tested for its potential as a flowering potted plant, using the growth retardant paclobutrazol. The treatments included a control, 2, 4, 8 and 16 mg activeingredient (a.i.) per pot and were applied when the longest leaves reached 15 cm. All treatments reduced perpendicular leaf height. Inflorescence heights were significantly affected by paclobutrazol.The flower spikes of plants treated with 2, 4 and 8 mg a.i. per pot were only marginally shorter than the control, while the height of plants treated with 16 mg was significantly reduced. All plants reached firstflower anthesis within a month from 22 weeks after planting. Flowering was staggered throughout the month, from the control through to plants treated with 16 mg a.i., with the control flowering from 166days after planting, gradually increasing to 178 for 2 mg, 181 for 4 mg, 183 for 8 mg, and 186 for 16 mg a.i./pot. The average number of flowers produced per pot significantly dropped with increasing strengthof a.i. applied. The control produced an average of three flowers while plants treated with 16 mg a.i produced less than one

Effect of the growth retardant Cycocel® in controlling the growth of Dombeya burgessiae

Pink dombeya (Dombeya burgessiae) was tested for its potential as a flowering potted plant, using the growth retardant Cycocel® (2-chloroethyl)-trimethylammonium chloride. The treatments included acontrol, 0.5, 1, 2 and 3 mg/L of Cycocel® per pot and were applied when seedlings reached 7 - 8 cm in height. All treatments significantly reduced plant height. The plants treated with 0.5 mg/L were only marginally shorter than the control, while the height of plants treated with 1, 2 and 3 mg/L Cycocel®, were greatly reduced. Increased Cycocel® concentrations decreased plant width in all treatments, as compared with the control. At all applied concentrations, the deterioration of foliage greenness wasobserved. The highest concentration of Cycocel® (3 mg/L) resulted in cycocel-induced chlorosis. This was followed by the 2, 1 and 0.5 mg/L respectively, all showing symptoms of chlorosis; however to a lesser extent. Cycocel® treated plants exhibited greener foliage in the new leaves formed in the weeks after application compared with the control. It is important to mention that the new leaves formed in the weeks after application were not affected, and were in fact darker green with the higher concentrations of Cycocel® treatments.The fresh and dry weights of plants severely decreased with the increased Cycocel® concentrations. The highest concentration (0.3% a.i.) caused the largest reduction, withplants in this treatment only weighing 38% of the total fresh weight of the control and 35% of the total dry weight

The potential of developing an in vitro method for propagating Strelitziaceae

Strelitzia spp. are highly valued as cut flowers and are of significant commercial value. Despite high demands, they have not been widely spread due to production constraints and are one of the few important cut flower  plants for which no uniform cultivars are available. The conventional methods of propagation are very slow due to the plants low rate of multiplication. Large scale propagation and cloning is therefore needed to exploit its potential. Despite the plants commercial importance, a method for micropropagation has not yet been  established. Tissue culture attempts of this plant have failed due to the oxidative browning of explants.  Wounded tissues release polyphenolic compounds which are detrimental to further development of explants. Only partial success and a low rate of multiplication have been obtained. This review explores the possibilities of developing an in vitro method for the successful propagation of Strelitzia spp.Key words: Strelitzia spp., activated charcoal, antioxidants, auxins, cytokinins, dark incubation, immatureembryos, media composition, wounding

Possible effects of regulating hydroponic water temperature on plant growth, accumulation of nutrients and other metabolites

Water temperature can affect many physiological processes during plant growth and development. Temperatures below or above optimum levels may influence plant metabolic activities positively or negatively. This may include accumulation of different metabolites such as phenolic compounds, reactive oxygen species (ROS), nutrient uptake, chlorophyll pigment formation, the photosynthesis process and finally the growth and development of the plant. The optimum temperature of the growthmedium can contribute to improving and optimising the earlier mentioned plant physiological processes. Information on how the temperature of hydroponic solution influences certain flowering plant production in glasshouses during the winter period is limited. This review suggests the possible benefits of regulating temperatures of the hydroponic solution with the aim of optimising production of flower in the glasshouse during winter periods.Keywords: Chlorophyll, nutrient uptake, phenolic compounds, photosynthesis rate, reactive oxygen specie

Effects of different combinations of Hoagland’s solution and Azolla filiculoides on photosynthesis and chlorophyll content in Beta vulgaris subsp. Cycla ‘fordhook giant’ grown in hydroponic cultures

The assessments of photosynthetic rate, stomatal conductance,  evapotranspiration, intercellular CO2 concentration and chlorophyll content in Beta vulgaris subsp. cycla ‘Fordhook Giant’ grown in hydroponic cultures containing different compositions of hydroponic solutions were evaluated in this study. The aim of the study was to quantify the effects of different combinations of Hoagland’s solution and Azolla filiculoides on photosynthesis processes and chlorophyll content in B. vulgaris grown in hydroponic cultures. The following treatments were evaluated in four replications: (1) Control (Hoagland’s solution minus N solution excluding Azolla; (2) Hoagland’s minus N solution including Azolla; (3) full Hoagland’s solution plus Azolla; and (4) full Hoagland’s solution excluding Azolla. Results show that photosynthetic rate, evapotranspiration, intercellular CO2 concentration and chlorophyll were generally higher in full Hoagland’s solution. This was closely followed by full Hoagland’s solution plus Azolla, and Hoagland’s minus N solution plus Azolla treatments. The lowest photosynthetic rates and chlorophyll contents were found in the control (Hoagland’s minus N solution) treatment.Keywords: Photosynthetic rate, stomatal conductance, evapotranspiration, intercellular CO2 concentration, chlorophyll a, chlorophyll bAfrican Journal of Biotechnology Vol. 12(16), pp. 2006-201

Edibility of Trachyandra ciliata (L.f.) Kunth- an underutilized vegetable from South African Western Cape coast: a review

The aim of Sustainable Development Goal 2 (SDG2) is to end hunger, improve food security and nutrition and promote sustainable crop production by 2050. However, climate change, increasing soil salinization and the inadequate availability of fresh water have negatively affected crop production around the world including South Africa, making it difficult to meet the required target. This necessitates the use of wild edible plants that are adapted to adverse conditions such as drought and salinity in order to mitigate this problem. The genus Trachyandra (Asphodelaceae) consist of three edible species (T. ciliata, T. divaricata and T. falcata) which are native to the dry saline environments of the western Cape coastal sand dunes. The genus is less studied with no record of cultivated species, although the existing literature states that T. ciliata, (wild cabbage) was originally used as a food source by the indigenous Khoi-san people who lived on the South African Cape coast. Colonization and removal of indigenous people from cultural lands led to erosion and detachment from the knowledge of the land and its useful plants. The species is used in selected restaurants where the inflorescence is steamed and eaten as a vegetable or added into a stew. This review explores the importance of Asphodelaceae family, T. ciliata as a vegetable crop and its potential as a pharmaceutical candidate. Furthermore, this review examines potential technological advances such as hydroponics that could be used for sustainable crop production of T. ciliata. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) was utilized in the selection of articles in this review. The existing literature provided useful information on the potential of T. ciliata as a vegetable crop and the importance of using halophytes to achieve food security. This appraisal is expected to serve as a template for researchers, food enthusiasts, potential farmers and policy makers who may be keen in exploring further nutritional composition and medicinal potential of this plant

Rooting success using IBA auxin on endangered Leucadendron laxum (PROTEACEAE) in different rooting mediums

Leucadendron laxum (Marsh rose Leucadendron) was tested for its rooting ability as an endangered plant species for reintroduction into the natural habitat, using IBA liquid hormone preparations and fourgrowth media. The treatments included a control, 500, 1000, 2000 and 4000 ppm concentrations. Four growth media, namely: bark and polystyrene; peat moss and polystyrene; bark, river sand andpolystyrene; and perlite and river sand were tested in an environmentally controlled greenhouse with bottom heat. The experiments used a randomised block design with 10 cuttings per treatment and 4 replicated four times. The results showed that the bark, sand and polystyrene medium had the highest (45%) significant survival rate when supplied with IBA at 500 ppm. The application of 1000 ppm of IBA in bark, sand and polystyrene medium significantly increased the number of roots per cutting (5) and produced the longest roots (4 cm). The bark and polystyrene medium supplied with zero IBA had the largest number of roots per cutting (6.5). The comparison of the four growth media showed that bark and polystyrene was the best medium that produced the highest and most significant callusingformation (30%), % of cuttings that rooted (28%), cuttings with a higher survival rate (57%), and cuttings with a higher number of roots (3.5) and the longest roots (7.35 mm). With regard to various IBAtreatments tested across all treatments, the IBA supplied at 1000 ppm produced greater root numbers when compared with all other treatments

The potential for increasing local employment and land owners’ income from wild harvested natural resources through sustainable farming practices

The potential for increasing local employment and land owners’ income from wild harvested natural resources through sustainable farming practices, 8th International Soil Science Congress on Land Degradation and Challenges in Sustainable Soil Management, Cesme, Turkey, 15-17 May 2012The Agulhas Plain contributes largely to the commercial indigenous cut flower industry of South Africa. The Plain is rich in biodiversity and harbours many endemic species, some of which are threatened with extinction due to over-exploitation. Commercial plantations have increased but many species of Proteaceae continue to be harvested from the natural habitat. A lack of training seems to exist in wild harvesting techniques as landowners are mostly self trained with low formal education. Training of landowners and seasonal workers in sustainable farming practices in cultivation and harvesting could assist in increasing awareness, rehabilitation and conservation of this sensitive habitat, which could then provide further income opportunities

The potential for increasing land owners’ income from wild harvested natural resources

The potential for increasing land owners’ income from wild harvested natural resources International Conference of Agricultural Engineering, Valencia, Spain, 8-12 July 201

The potential for increasing local employment and land owners’ income from wild harvested natural resources through sustainable farming practices

The potential for increasing local employment and land owners’ income from wild harvested natural resources through sustainable farming practices 8th International Soil Science Congress on Land Degradation and Challenges in Sustainable Soil Management, Cesme, Turkey, 15-17 May 201