The physiology of germination and dormancy in seeds of gynandropsi gynandra L. Briq syn Cleome gynandra L. (Cleomaceae).

Masters Degree. University of KwaZulu-Natal, Pietermaritzburg.The “spider plant” Gynandropsis gynandra L. Briq,” is an important traditional leafy vegetable in many parts of Africa. The species is considered underutilized and has been mainly neglected by research systems. Yields are generally low and this has been attributed to a number of factors including low and non-uniform seed germination. This study sought to gain a deeper understanding of factors influencing germination and dormancy in spider plant seeds. The specific objectives were to, (i) describe and document the phenotypic characteristics and mineral composition of seeds of 29 G. gynandra accessions from diverse regions, (ii) determine the pattern of seed germination and dormancy development in seeds of different spider plant accessions and their crosses and (iii) assess the storage potential of spider plant seeds using artificial aging. To achieve these objectives, accessions originating from West Africa, East Africa and Asia were used. In the first experiment, seeds of the accessions from the three regions were subjected to scanning electron microscopy to study seed structure and mineral composition. In the second experiment, seeds from different accessions were planted in pots in a tunnel and data recorded at bi-weekly intervals during development until maturity on the following variables: seed fresh and dry mass, seed moisture content, germination capacity, mean germination time (MGT) and electrical conductivity (EC). In the third experiment, seeds that had been stored for four months and freshly harvested were subjected to the accelerated aging to test for storage potential. The same variables that were in the second experiment were measured in the third experiment in addition to tetrazolium test (TZ). Data analysis was done using R software version 3.5.1. Eight mineral elements were identified in the seeds of spider plant, and the internal and external structure of the seed was revealed. The results showed significant differences among spider plants accessions with regard to shape, size, mineral composition, germination percentage and mean germination with Asian accessions showing a higher germination percentage. The study revealed that spider plant fresh seeds exhibited a physiological dormancy which can be broken by heating at 41°C for 3 days and/or gibberellic acid (0.001%), depending on the genotype. However, the degree of dormancy varied from one genotype to another as follows: weak (% germination >50%), intermediate (% germination>6%<50%) and strong (% germination<6%). Moreover, the study found that a saturated solution of 40% NaCl for 48 h could be used to evaluate the physiological quality in spider plant seeds during storage. It is suggested that further experiments using the diversity observed in the species be conducted to select genotypes with weak dormancy in order to improve the germination capacity in the species

Origin-dependence of variation in seed morphology, mineral composition and germination percentage in Gynandropsis gynandra (L.) Briq. accessions from Africa and Asia

Background: Spider plant [Gynandropsis gynandra (L.) Briq.], an economically promising African leafy vegetable, characterized for leaf yield components and nutritive quality, exhibits poor seed germination that hinders a wider expansion of the crop in urban and periurban horticultural systems. So far, there is little information pertaining to seed morphological traits and mineral elements content that may be associated with higher seed germination. This research investigated the hypothesis that spider plants from different geographical areas exhibited differences in seed mineral composition, morphological traits, and germination capacity. To this end, twenty-nine accessions of Gynandropsis gynandra from West and East-Southern Africa, and Asia were screened for variation in seed size (area, perimeter, length, width), 10-seed weight, mean germination time, germination percentage and mineral content variations. The scanning electron microscopy (SEM), light microscopy and energy dispersive spectroscopy (EDS) solution were used to study seed morphology and mineral composition. Results: We show for the first time the external and internal structure of the seeds of Gynandropsis gynandra and measured eight mineral elements, including carbon (C), oxygen (O), magnesium (Mg), aluminium (Al), phosphorus (P), sulphur (S), potassium (K) and calcium (Ca). The accessions differed significantly (p < 0.001) with respect to seed size (area, perimeter, length, width), 10-seed weight, mean germination time and germination percentage. The hierarchical cluster analysis based on fourteen variables grouped the accessions into three distinct clusters, partially dependent on their geographical origin. Asian accessions exhibited smaller seeds and recorded higher values in terms of germination percentage. West African accessions had bigger seeds but with lower germination percentage. Variation in minerals such as potassium, carbon, and calcium content showed different patterns according to geographical origins. Conclusion: Smaller seeds in G. gynandra exhibited better germination capacity. The Asian germplasm is a potential source of cultivars with a higher germination percentage for improving seed quality in the species.</p

Exploring teachers’ experiences of the teaching of Mathematics in the Intermediate Phase in (Grade 4-6) Nongoma Circuit)

Masters Degree. University of KwaZulu Natal, Pietermaritzburg.The “spider plant” Gynandropsis gynandra L. Briq,” is an important traditional leafy vegetable in many parts of Africa. The species is considered underutilized and has been mainly neglected by research systems. Yields are generally low and this has been attributed to a number of factors including low and non-uniform seed germination. This study sought to gain a deeper understanding of factors influencing germination and dormancy in spider plant seeds. The specific objectives were to, (i) describe and document the phenotypic characteristics and mineral composition of seeds of 29 G. gynandra accessions from diverse regions, (ii) determine the pattern of seed germination and dormancy development in seeds of different spider plant accessions and their crosses and (iii) assess the storage potential of spider plant seeds using artificial aging. To achieve these objectives, accessions originating from West Africa, East Africa and Asia were used. In the first experiment, seeds of the accessions from the three regions were subjected to scanning electron microscopy to study seed structure and mineral composition. In the second experiment, seeds from different accessions were planted in pots in a tunnel and data recorded at bi-weekly intervals during development until maturity on the following variables: seed fresh and dry mass, seed moisture content, germination capacity, mean germination time (MGT) and electrical conductivity (EC). In the third experiment, seeds that had been stored for four months and freshly harvested were subjected to the accelerated aging to test for storage potential. The same variables that were in the second experiment were measured in the third experiment in addition to tetrazolium test (TZ). Data analysis was done using R software version 3.5.1. Eight mineral elements were identified in the seeds of spider plant, and the internal and external structure of the seed was revealed. The results showed significant differences among spider plants accessions with regard to shape, size, mineral composition, germination percentage and mean germination with Asian accessions showing a higher germination percentage. The study revealed that spider plant fresh seeds exhibited a physiological dormancy which can be broken by heating at 41°C for 3 days and/or gibberellic acid (0.001%), depending on the genotype. However, the degree of dormancy varied from one genotype to another as follows: weak (% germination >50%), intermediate (% germination>6%<50%) and strong (% germination<6%). Moreover, the study found that a saturated solution of 40% NaCl for 48 h could be used to evaluate the physiological quality in spider plant seeds during storage. It is suggested that further experiments using the diversity observed in the species be conducted to select genotypes with weak dormancy in order to improve the germination capacity in the species

Ten years of Gynandropsis gynandra research for improvement of nutrient-rich leaf consumption : Lessons learnt and way forwards

This article reveals progress and gaps in spider plant (Gynandropsis gynandra Syn. Cleome gynandra) research to date. It synthesises the current knowledge in systematics and botany, geographical distribution, nutrient content, and health values as well as the agronomic practices related to the species. This article further presents the germplasm availability, status, and places of conservation around the world to exploit the extant genetic diversity for genomics-assisted breeding and seed systems development. It describes how various parts of the plant have been used and the potential for economical revamping and further industrial valorisation. Nutrient content and phytochemical diversity across cultivation systems and geographical ranges and known health attributes were analysed to identify gaps and bottlenecks for fostering further investigations for industrial food and drug production