Browsing by Author "Chimphango, Samson B M"

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    Absolute values only show part of the whole : evidence of P limitation in legumes in the CFR from N:P ratios
    (2008) Duckworth, Greg; Chimphango, Samson B M
    The influence of nutrient limitation in legumes and non-legumes was studied in the field, on nutrient poor and nutrient rich sites in the CFR in the western Cape of South Africa. 6 species of legume and 11 species of non-legume, along with their corresponding soils were taken for macro and micronutrient analysis. Results indicate that legume soils were more nutrient rich than non-legume soils, with Na, K, Mg, Ca and C being higher in at least one of the legume soils. pH was significantly lower in 2 of the legume soils. Resultantly, this enhancing nutrient availability. Legume plants were more nutrient rich than non-legumes, with significantly higher Zn, Fe, P, C and N concentrations, and lower C:N and C:P ratios. Legumes appeared to have a more efficient nutrient uptake strategy. However, the higher N:P ratio of legumes suggests that despite higher absolute nutrient concentrations, legumes were P limited. This study confirms that legumes are more P stressed than non-legumes in the CFR.
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    Aspalathus and Podalyria legumes balance acquisition of phosphorus and nitrogen for growth in nutrient poor fynbos soils
    (2015) Maistry, Pravin Mark; Chimphango, Samson B M; Muasya, A Muthama; Valentine, Alex J
    Legume species nodulate and grow successfully in the Core Cape Subregion, a Mediterranean-climate ecosystem with fynbos vegetation found on infertile soils. The physiological mechanisms enabling tolerance of low availability of phosphorus (P) are yet to be reported in Cape legume species such as Aspalathus linearis and Podalyria calyptrata; species that demonstrated traits typical of plants from nutrient poor soils. In the three research chapters of the thesis, it was anticipated that low P supply would limit plant growth and increase expression of traits for P acquisition.
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    Edaphic factors and rhizobia influence the distribution of legumes (Fabaceae) in the Core Cape Subregion of South Africa
    (2018) Dludlu, Meshack Nkosinathi; Muasya, Muthama; Chimphango, Samson B M
    Fabaceae is the second most speciose plant family in the Core Cape Subregion (CCR) of South Africa, a Mediterranean type ecosystem, with mostly nutrient-poor soils. A majority of the legumes occurring in this region belong to the predominantly nitrogen-fixing subfamily Papilionoideae and they employ a variety of strategies for nutrient acquisition. However, legumes are neither uniformly nor randomly distributed in the CCR landscape. Instead, distinct legume species assemblages tend to occupy particular habitats within the landscape. The drivers of this distribution pattern are yet to be determined. In this thesis, it was hypothesized that edaphic factors (soil chemical and physical characteristics) and the distribution of rhizobia have influenced legume distributions in the CCR landscape. The influence of edaphic factors on the distribution of legume species assemblages in the Cape Peninsula (a microcosm of the CCR) is the subject of the second chapter of the thesis. It was hypothesized that the composition of legume species assemblages is correlated with soil physical and chemical properties and that the interaction of Phosphorus (P) and the three cations that often bind P, i.e. Aluminium, Calcium and Iron, making it unavailable to plants, drive legume species assemblages in the landscape. Soils from 27 legume sites, spanning all major soil types of the Cape Peninsula, were analysed for 31 chemical and physical properties. Surveys of legume species present at each site were conducted to generate a presence/absence matrix. Canonical correspondence analysis was used to test for a correlation between legume species composition and edaphic factors. The strength of the association between legume species composition and site groupings based on edaphic properties was assessed using indicator species analysis. A significant correlation between edaphic factors and species composition was found and the key edaphic parameters driving the relationship were clay content, iron (Fe), potassium (K), sulphur (S) and zinc (Zn). Indicator species, characteristic of the various edaphic habitats were also identified. These findings indicate that distinct edaphic habitats are occupied by discrete legume species assemblages, implying a significant influence of edaphic factors on the legume distributions. Chapter three of the thesis sought to determine if the ecological parameters; altitude, pH and soil type influence the distribution of the two main rhizobial genera (Burkholderia and Mesorhizobium) that nodulate various legumes of the CCR, and to determine the diversity and phylogenetic position of rhizobia that associate with the narrowly distributed and rare Indigofera superba in the CCR. The first objective was pursued through molecular characterisation of rhizobial strains isolated from nodules of legume species collected in the field across the Cape Peninsula. DNA sequences for 16S rRNA, recA and nodA were combined with data from a previous study that sampled broadly within the CCR and phylogenetic analyses were conducted. Tests for phylogenetic signals for the three ecological parameters were conducted, using the D statistic for soil type and Pagel’s λ for altitude and pH. These analyses were used to test the hypothesis that closely related species occupy similar habitats with respect to each of the three ecological parameters. For the study of rhizobial symbionts of Indigofera superba, field nodules were sampled from multiple populations across its distribution range and a phylogeny of its symbionts was reconstructed in a matrix that included symbionts of diverse legumes from different habitats within the CCR. The results showed that Burkholderia is restricted to acidic habitats, while Mesorhizobium occurs in both acidic and alkaline habitats. Additionally, both rhizobial genera showed significant phylogenetic clustering for pH and most soil types. However, none of the genera showed a phylogenetic structure with respect to altitude. These findings indicate that pH and soil type influence the distribution of rhizobia in the CCR. Implications of these findings for the distribution of legumes in the landscape are discussed. For the narrowly distributed I. superba, the results showed that it associates with diverse strains within the genus Burkholderia and such strains are not phylogenetically distinct from strains isolated from localities outside its distribution range. These findings lead to the hypothesis that I. superba does not exhibit rhizobia specificity at the intrageneric level. Testing of this hypothesis through analysis of its nodulation capability on soils from outside its distribution range is recommended. The fourth chapter of the thesis determined the extent of horizontal gene transfer among rhizobial genera in the Core Cape Subregion (CCR) of South Africa and reconstructed the ancestral symbionts of the legumes. Phylogenies of two chromosomal genes (16S rRNA and recA) and one nodulation gene (nodA) of rhizobia, isolated from diverse legumes in the CCR, were reconstructed using Bayesian and Maximum Likelihood techniques. A cophylogenetic analysis was used to test for congruence between the chromosomal and the nodA phylogenies. Five genera of rhizobia (Bradyrhizobium, Burkholderia, Ensifer, Mesorhizobium and Rhizobium) were studied. A phylogeny of the legumes was reconstructed from matK and rbcL DNA sequences and it was used to reconstruct their ancestral rhizobia, using Bayesian methods. The chromosomal phylogeny of the rhizobia was mostly incongruent with that of nodA, indicating potential horizontal inheritance of the latter. The nodA genes of Burkholderia, Mesorhizobium and Rhizobium had different evolutionary histories from their counterparts in other parts of the globe. Burkholderia was reconstructed as the ancestral symbionts of the CCR legumes. Evidence of co-diversification between the legumes and their symbionts was observed and this highlights a potential role of the legume-rhizobia interaction to the high diversity of legumes in the CCR. Finally, the availability of compatible rhizobia and their competitive ability are discussed as possible drivers for the lack of shared legumes between the CCR’s Fynbos biome and the Kwongan of Australia. Overall, the study shows that edaphic factors and biotic interactions (rhizobia) have significant influence on the distribution of legumes in the Cape Peninsula and the larger Core Cape Subregion of southern Africa. These findings are consistent with the theory that edaphic factors and biotic interactions have a strong influence on species distributions at local and site spatial scales.
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    Phenotypic characterization of rhizobia isolates and distribution of Burkholderia rhizobia in the Core Cape Subregion
    (2016) Sinyanya, Kolisa Yola; Chimphango, Samson B M; Muasya, A Muthama
    The Core Cape Sub-region is well known for its low nutrient, low pH soils which harbour a variety of alpha and beta- Proteobacteria associated with a diversity of legume species. Soil bacteria are important for ecological processes and are influenced mostly by edaphic factors such as salinity and pH, and climatic conditions such as temperature. Recent studies have shown that Burkholderia form nitrogen fixing molecular associations with members of, among others, tribes Crotalarieae, Podalyrieae and Indigofereae. Selected rhizobia that included Burkholderia and Mesorhizobia, the large genera in the isolated rhizobia, and representing beta- and alpha- Proteobacteria were phenotypically characterized to determine the tolerances of Cape isolates to abiotic conditions. In a second study, glasshouse trapping experiments were conducted using legume species Podalyria calyptrata and Indigofera filifolia grown in 13 soils collected from diverse localities of the CCR, to determine the phylogenetic distribution of Burkholderia species in diverse soils of the CCR. To phenotypically characterize rhizobia isolated from a previous study, 29 isolates from representative legume-nodules of 13 different localities were grown under laboratory conditions. Isolates were phenotypically characterized for colony morphology, growth temperature, carbon source, salinity and pH tolerance. Morphological results revealed that majority of the tested isolates were white opaque, rod shaped and fast growing. Exceptions were found in colour where five strains produced a milky pigment, two were watery translucent; observation of bacteriod-shape among six symbionts; and one isolate grew after 7 days.
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    Phosphorous uptake rate in two low phosphorous updated species, Aspalathus linearis and Podalyria calyptrata
    (2011) Basic, Dunja; Chimphango, Samson B M; Cramer, Michael D
    Due to the low P nature of soils within the fynbos biome of the Cape Floristic Region, plants have developed numerous mechanisms which enable them to better acquire phosphorous. A number of species have been reported to have specialised root morphologies (root clusters, mycorrhizae) that enhance P uptake. Plants may also down-regulate the uptake of P by decreasing the expression of genes that encode P transporters. Two Fabaceae species, Podalyria calyptrata and Aspa/athus linearis, were grown in hydroponics for 5 months at a low P supply of 4μM and P-depletion studies were conducted thereafter at 5 levels of external P (4, 10, 20, 50 and lOOμM). Growth rates (biomass accumulation) were also calculated as were root to shoot ratios for both species. A. linearis had a higher uptake rate than P. calyptrata. While the fresh biomass growth rate was similar in both species, P. calyptrata had a higher dry weight root to shoot ratio than A. linearis. The results showed that both species exhibited a lack of response to increasing P concentrations and had similar RGRs. Their uptake rates differed significantly (p<0.05) and this was likely due to their different root:shoot ratios. This indicates that both species would effectively grow in low P soils and in the case of P. calyptrata, in high P soils as well.
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    Phylogenetic relationships and the effects of edaphic heterogeneity on the distribution of Wiborgia (Fabaceae) in the Greater Cape Floristic region
    (2016) Moiloa, Ntwai; Muasya, A Muthama; Chimphango, Samson B M
    The Greater Cape Floristic Region (GCFR) is divided into two subregions, the Core Cape Subregion (CCR) and Extra Cape Subregion (ECR), which are mainly characterized by Fynbos and Succulent Karoo biomes, and are recognized among global biodiversity hotspots. The soils in the ECR are mostly shale derived and richer in nutrients compared to the CCR which is characterized by nutrient-poor sandstone soils mainly from the Cape System. The Fabaceae (Leguminosae) is the second largest family in the CCR with a total of about 764 species (belonging to 43 genera, of which 83% of the species are endemic to the CCR), and sixth largest in the ECR with about 140 species currently recognised with 39.3% of these species endemic to the ECR. Wiborgia Thunb. is a legume genus made up of 9 perennial shrub species of height 0.5-3.0 metres, with distinct ascending to erect habit, which share morphological similarities with some Lebeckia, especially sect. Viborgoides currently referred to as Wiborgiella. The aim of this dissertation was to understand the evolution and biogeography of the genus Wiborgia in the GCFR. This involved (i) inferring phylogenetic relationships within the genus using multiple molecular markers and testing the monophyly and the support of Dahlgren's (1975) morphological subgeneric classification; (ii) determining nutritional characteristics of soils occupied by different Wiborgia species and compare them with sites where Wiborgia species have not been recorded to occur and testing whether Wiborgia species occupy habitats with similar nutrient concentrations; (iii) evaluating the potential of Wiborgia species to grow and nodulate in soils from within and outside distribution range and characterizing of rhizobia nodulating Wiborgia species in field and glasshouse conditions. Phylogenetic relationships in Wiborgia were inferred using multiple molecular markers (ITS, rpl32-trnL, rps16, trnS-trnG, and trnT-trnL) and the data were analysed using model based approaches (Maximum Likelihood, Bayesian inference). Wiborgia was well supported as monophyletic and sister to both Wiborgiella and Aspalathus, with Wiborgiella humilis well supported as being part of the Wiborgiella clade. Within the Wiborgia clade, two strongly supported subclades were observed. In subclade 1, W. tetraptera was strongly supported as sister to W. fusca, whilst W. monoptera was strongly supported as sister to W. incurvata. In subclade 2, a novel well-supported sister relationship between W. mucronata and W. tenuifolia was observed. Wiborgia obcordata, the only species in Dahlgren's subgenus Wiborgia, was found to be embedded within subgenus Pterocarpia and thus the subgenera classification of Dahlgren was not supported. It was also identified that sister species pairs (W. incurvata and W. monoptera; W. fusca and W. tetraptera; W. tenuifolia and W. mucronata) all showed the tendency to co-occur or have overlapping distribution ranges, and showed subtle differences in floral morphology and habitats.
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    Plant growth, stress tolerant traits and regulation of heat activated proteins in Aspalathus linearis (Burm. f.) R. Dahlgren exposed to elevated temperature and drought
    (2020) MacAlister, Dunja; Muasya, A Muthama; Crespo, Olivier; Chimphango, Samson B M
    Climate change is increasingly becoming a concern on plant growth, as seen in the increased number of warmer days and nights as well as an increased occurrence of heat waves, and drought periods globally. The Intergovernmental Panel on Climate Change has stated that global surface temperatures are constantly increasing and are likely to exceed 2 °C, compared to average temperatures in 1900, by the end of the 21st century. Changes in precipitation will also become more erratic, with high latitude and mid-latitude areas expected to have increases and decreases in rainfall respectively, while already dry areas will have increased frequencies of drought. Regions with Mediterranean climates, such as the Western Cape in South Africa, are particularly vulnerable to these climate impacts, with models and studies showing that there are already significant increases in temperatures, shifts in later winter rainfall and an increased severity of flooding. These climatic changes will impact both natural and agricultural plant species growth and distribution due to the changes in suitable growing conditions and regions. Plants are already exposed to a wide variety of environmental factors, each of which influences the growth, and deviations from the optimal conditions is considered abiotic stress and negatively affects plant growth. Plants in the field are rarely affected by only one stress as they are frequently exposed to a combination of abiotic stresses and with the changes in climate, plants will likely be experiencing abiotic stress such as heat and drought stress simultaneously. The aim of this thesis was to determine the effects of heat and drought on the plant growth and physiological performance of one of the most important indigenous commercial crops in South Africa, Aspalathus linearis (Burm.f.) R. Dahlgren, better known as rooibos tea, known for its many health benefits. This was achieved by focusing on three objectives: (1) determining the effects of temperature on plant growth and identifying the thermotolerant traits of the plants grown in the field along a temperature gradient, (2) determining the heat activated proteins and associated mechanisms for heat tolerance in field grown plants and (3) determining the physiological and morphological responses of A. linearis grown under two moisture regimes and later exposed to drought. The results for objective one are presented in chapter two, where a field study was conducted to observe the effects of temperature on the growth and stress tolerant traits of A. linearis grown at four farms sites in the Cederberg, South Africa along a temperature gradient. The four sites represent the rooibos farming area, from coolest to warmest respectively; Aurora (alt. 93 m), Citrusdal (alt. 588 m), Clanwilliam (alt. 312 m) and Uitsig (alt. 344 m). Aurora was also situated closest to the coastline, ∼18 km, compared to the other farms. The traits observed were changes in gas exchange, carbohydrate concentrations, phenolics and pigments, along with biomass, over a two-year period. Aspalathus linearis plants showed evidence of transpirational leaf cooling during summer and this, combined with lower chlorophyll and high phenolic content, could be considered acclimatized adaptive changes allowing the plants to mitigate the heating effects of elevated temperatures. Chapter three presented the results for objective two where the proteome of A. linearis was analysed from field plants along a temperature gradient. Protein samples were collected from the plants concurrently with the physiological samples for the previous chapter. These protein samples were quantified and then functionally annotated using the OrthoDB and UniProt databases. Overall, a total of 180 proteins were differentially expressed in the plants during exposure to high temperatures in the field. Of these 180 proteins, 113 were more upregulated in the cooler sites, Aurora and Citrusdal, and 67 proteins were more upregulated in the hotter sites, Clanwilliam and Uitsig thus indicating that with increasing temperatures there is a downregulation of proteins expressed during heat stress. From the 180 proteins, there were six main proteins involved in photosynthesis or light harvesting in A. linearis, with four of the six proteins upregulated in plants grown at Aurora, the cooler site, and in the hottest site, Uitsig. This agrees with results from chapter two, where plants from Aurora had superior photosynthetic rates compared to the other plants therefore allowing them to grow and produce better biomass. The hotter sites upregulated heat shock proteins more than the cooler sites, suggesting that their expression could be enhancing the thermotolerance of A. linearis plants through their chaperone activity where they protect other proteins against denaturation. There were also numerous proteins expressed in the plants which were related to oxidationreduction processes and antioxidants, most of which were expressed in the hottest site, Uitsig. One of the main concerns for plants during heat stress is the oxidative damage brought on by reactive oxygen species, and the expression of these proteins indicates that these proteins are contributing to the plants' thermotolerance through the production of antioxidant phenolic compounds as was seen in chapter two. In chapter four, a glasshouse study was conducted where plants were grown at two different moisture regimes (field capacities, FC) and then exposed to drought and both physiological and morphological parameters were measured. Morphological parameters measured included plant biomass, root/shoot ratios, total root length, average root diameter, total root surface area and specific root length. Physiological parameters measured were gas exchange, carbohydrate and phenolic concentrations, pigment concentrations, leaf relative water content and water potential. During drought, the gas exchange, relative water content and nonstructural carbohydrates in leaves were all reduced, while chlorophyll concentrations remained constant. Aspalathus linearis plants also had reduced stomatal conductance and transpiration, increased root/shoot ratios, root length and antioxidants such as polyphenol in leaves under drought conditions. Overall, changes in soil nutrients, including boron, available phosphorus, manganese and copper, and increasing temperatures had a negative impact on crop biomass, however, the phenolic content, which is a measure of tea quality, did not vary with sites. This suggests that farmers who are planning on shifting their rooibos farming further south of Cederberg, could still achieve good growth and high yields without compromising the quality of the tea. It was also seen that A. linearis plants upregulated heat shock proteins, along with proteins involved in antioxidant compounds particularly in the hotter sites thereby playing a critical role in their acquired heat-stress tolerance. Plants in the cooler sites upregulated proteins involved in photosynthesis and chlorophyll production, therefore allowing them to have higher photosynthetic activity and subsequently higher productivity. The up and down regulation was based on comparing the warmer sites (heat-stressed) to the cooler sites (control). The plants grown at lower FC and then droughted, exhibited drought tolerant mechanisms which included higher root/shoot ratios as well as thinner roots, both of which are effective for water and nutrient uptake. Overall, plants in the 30 % FC treatment recorded lower Pmax, gs and E after three days in the drought conditions while 70 % FC plants were only affected after five days. Furthermore, plants grown under low moisture (30 % FC) conditions produced 50 % lower biomass compared to plants grown under adequate moisture (70 % FC) conditions. This implies that low rainfall and the occurrences of dry spells and drought, associated with climate change are likely to reduce the production of A. linearis in the Cederberg area. The combination of both field work and glasshouse studies have provided insight into how these plants are affected by both heat and drought stress, as well as declining soil nutrients such as calcium, magnesium, manganese iron, copper and potassium. Aspalathus linearis is tolerant to high temperatures as well as dry conditions, however, more needs to be explored with regards to their thresholds particularly since climate change is likely to continue in the near future and eventually moving farming south will no longer be an option for farmers.
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    Taxonomy and evolutionary studies on the genus Psoralea L. (Psoraleeae, Fabaceae)
    (2016) Bello, Abubakar; Muasya, A Muthama; Chimphango, Samson B M
    Psoraleeae is a tribe of the papilionoid legumes in Fabaceae comprising ca. 223 species in nine genera. Members of Psoraleeae are distributed worldwide, though they mainly occur in the temperate biomes. Of these, ca. 60% of the species (mostly in Otholobium and Psoralea) are endemic to southern Africa predominantly in the Greater Cape Floristic Region (GCFR). The genus Psoralea, consisting of 75 species endemic to southern Africa, is the second most speciose legume in the GCFR after Aspalathus (280 species). This thesis, consisting of a literature review, three research chapters and synthesis, studies the taxonomy, evolutionary history and biogeography of Psoraleeae with an emphasis on Psoralea.
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    Thermo and drought tolerance markers and regulation of heat stress proteins for chickpea (Cicer arietinum L.; Fabaceae) production in NE South Africa
    (2020) Makonya, Givemore Munashe; Chimphango, Samson B M; Ogola, Ochanda JB; Muasya, A Muthama; Olivier, Crespo
    Chickpea (Cicer arietinum) is an important legume crop globally ranked third after dry bean (Phaseolus vulgaris) and field pea (Pisum sativum). It constitutes 20% of the total global pulse production and around 95% of its production and consumption takes place in developing countries. Major constraints to chickpea production in sub Saharan Africa (SSA) have broadly been related to abiotic stresses, particularly drought and heat stresses, predicted to increase due to the global climatic changes.Dueto the imperativeness of research for identifying heat tolerance markers for potential chickpea genotype selection, in chapter two of the thesis, the response of four chickpea genotypes to a natural temperature gradient in the field was assessed using chlorophyll fluorescence, non-structural carbohydrate, gas exchange and grain yield. Field experiments were carried out in two winter seasons at three locations with known differences in temperature in NE South Africa. Results showed two genotypes (Acc#3 and Acc#7) were tolerant to heat stress with an Fᵥ/Fₘ of 0.83-0.85 at the warmer site, while the two sensitive genotypes (Acc#RR-2 and Acc#8) showed lower Fᵥ/Fₘ of 0.78-0.80. Both chlorophyll fluorescence measurements: dark-adapted Fᵥ/Fₘ and Fq'/Fₘ' (where Fq' =Fₘ'–F) measured at comparable high light levels correlated positively with grain yield. The two tolerant genotypes also showed higher photosynthetic rates,starch, sucrose and grain yield than the sensitive genotypes at the warmer site. However, these parameters were consistently higher at the cooler than at the warmer sites. It was concluded that genotypes Acc#RR-3 and Acc#7 are heat tolerant and chlorophyll fluorescence and leaf carbohydrates are suitable tools for selection of heat tolerant chickpea genotypes under field conditions. The coolest site of Polokwane showed favourable conditions for chickpea production.Heat and drought stresses are two abioticfactors that often occur simultaneously and are predicted to increase, consequently hampering plant growth. Response of different species to either stresses is well documented but information on the response of the same genotypes to both stresses in chickpea is limited. We aimed to determine whether previously noted heat stress tolerant genotype (Acc#7) is drought tolerant and the heat sensitive (Acc#8) is drought sensitive, and whether intermittent moisture supply at vegetative stage would induce priming effect to later drought at flowering. At vegetative stage, plants were divided into three groups, non-stressed (watered to 75% field capacity (FC), severe water stress (moisture-withholding for 14 days) and treated to 40% FC throughout the experiment (mild-stress), with recovery for the severely stressed plants after which they were stressed (double-stress) at flowering. Drought treatments at vegetative and flowering growth stages decreased physiological parameters and biomass accumulation in both genotypesexcept low water supply at 40% FC that decreased biomass in Acc#7 but not Acc#8. Double drought stress resulted in priming effect in Acc#7, having higher biomass, chlorophyll fluorescence, stomatal conductance, net photosynthesis, and relative water content in comparison to the introduction of stress only at flowering growth stage, as well as in comparison to Acc#8. These results showed that both Acc#7 and Acc#8 are sensitive to drought whereas after priming Acc#7 is better acclimated to drought than Acc#8 associated with osmotic adjustment on leaf relative water content (RWC) and higher capacity to protect photosynthetic activity, making Acc#7 potentially ideal for areas associated with intermittent drought spells. This observation, however, disapproved the hypothesis that Acc#7 is more drought tolerant than Acc#8 but is rather better acclimated than Acc#8, because of its superiority only in primed plants and not those stressed only at either vegetative or flowering stages. The findings emphasise the importance of matching chickpea physiological performance to expected rainfall amounts and distribution in drought prone areas during genotype selection. Chapter four of the thesis was an interrogative proteome analysis of the differences in the heat tolerant and sensitive chickpea (Cicer arietinumL.; Fabaceae) genotypes along a temperature gradient under field conditions which will help in identifying the molecular mechanisms involved in the crop's tolerance. Few studies have thus far combined chickpea physiological and proteome analysis to elucidate the changes in abundance and/or activity of relevant enzymes and expression of heat responsive proteins. In this study, analyses of chlorophyll concentrations, gas exchange, flavonoids and anthocyanin concentrations from a chamber experiment, as well as proteomic parameters from field studies in both the heat tolerant and sensitive genotypes are presented. The heat tolerant genotype Acc#7 maintained unaltered physiological performance at flowering growth stage when exposed to high (35/30°C) and moderate (30/25°C) heat stress, under climate chamber conditions compared to the two heat susceptible genotypes (Acc#RR-2 and Acc#8). Results from the proteomic studies showed an up-regulation in proteins related to protein synthesis (e.g. ribulose bisphosphate carboxylase/oxygenase activase), intracellular traffic (e.g. mitochondrial dicarboxylate/tricarboxylate transporter DTC), defence (e.g. HSP70) and transport (e.g. GTP-binding protein SAR1A-like) in heat tolerant Acc#7 compared to the susceptible Acc#8. Results from KEGG analyses support the involvement of probable sucrose-phosphate synthase and sucrose-phosphate phosphatase proteins in the starch and sucrose pathway,that were up-regulated in the heat tolerant genotype Acc#7. This result was in support of our earlier report where tolerant genotype Acc#7 had higher leaf starch and sucrose concentrations in comparison to the susceptible genotype Acc#8. The presence of these differentially regulated proteins including HSP70, ribulose bisphosphate carboxylase/oxygenase activase, plastocyanin and protoporphyrinogen oxidase shows their potential role in field grown chickpea tolerance to heat stress at flowering growth stage. In conclusion, chlorophyll fluorescence (both Fᵥ/Fₘ and Fq'/Fₘ') and leaf carbohydrates were identified as selection markers that can potentially be used for chickpea phenotyping for heat stress under field conditions with the chlorophyll fluorescence parameters correlating positively with seed yield. Due to its higher biomass, chlorophyll fluorescence (Fᵥ/Fₘ), stomatal conductance, net photosynthesis and RWC, heat tolerant genotype Acc#7 was identified to have better adaptive tolerance to drought stress after priming through exposure to intermittent dry spells than Acc#8. Furthermore, under controlled climate chamber conditions, Acc#7 consistently showed characteristics of tolerance to heat stress while Acc#RR-2 and Acc#8 were heat susceptible. Higher chlorophyll fluorescence, grain yield, chlorophyll concentrations, gas exchange, flavonoids and anthocyanin concentrations for Acc#7 compared to Acc#8 in the climate chamber was further validated by the higher up-regulation of proteins involved in protein synthesis, intracellular traffic, defence and transport in Acc#7 compared to Acc#8. The incorporation of proteomics in heat and drought stress studies will potentially help further the understanding of mechanisms by which the crop responds to these stresses.