Sulphur fertilization on biochemical constituents of cabbage (Brassica oleracea var. capitata. L) in non-calcareous soil of Coimbatore district, Tamil Nadu

Sulphur is the fourth most important plant nutrient after nitrogen, phosphorus, and potassium, and it is becoming increasingly crucial in high-quality crop production (Bhoyar., 2019). Since limited work has been carried out regarding different sulphur sources on cabbage production in the Coimbatore district, the present study was undertaken to investigate the sulphur sources and levels on various biochemical constituents of cabbage. Hence a field experiment was conducted in the farmer’s field at Viraliyur village, Thondamuthur block of Coimbatore district, Tamil Nadu to assess the effect of sulphur fertilization on improving the biochemical constituents of cabbage hybrid Saint. There were four different S sources (Elemental sulphur, Potassium sulphate, Gypsum, Single super phosphate) applied at five levels (0, 20, 40, 60 and 80 kg ha-1) and replicated thrice in a factorial randomized block design. The crop was fertilized with a Soil Test Crop Response-prescribed dose of NPK (200:125:25 kg ha-1). The crop was harvested on 90th day and cabbage heads were analysed for various biochemical constituents like ascorbic acid, total soluble solids (TSS), titratable acidity (TA), chlorophyll content, glucosinolates (GLs), total phenol content (TPC), sulphur containing amino acid (methionine) and antioxidant enzyme activity (peroxidase). The influence of S fertilizers on biochemical constituents increased significantly with increasing levels of sulphur fertilization up to 80 kg S ha-1 excluding ascorbic acid content. The pooled data showed that gypsum applied at 80 kg ha-1 registered the maximum GLs (69.0 µmol g-1), TPC (31.9 mM 100g-1), methionine (32.3%), peroxidase activity (0.70 units min-1mg-1), TSS (7.64 0Brix), TA (0.64%), ascorbic acid (61.4 mg 100g-1) and total chlorophyll (1.21 mg g-1) in cabbage head. The lowest content of biochemical constituents viz., GLs (34.1 µmol g-1), TPC (8.10 mM 100g-1), methionine (17.6%) and peroxidase (0.31 units min-1mg-1) were observed in control applied NPK alone. There were positive and significant changes in the biochemical constituents of cabbage due to S application which confirms the improvement in the quality of cabbage head. The study concluded that gypsum was the better sulphur source for improving the quality of cabbage.

Zinc (Zn) and Iron (Fe) Fertilization for Improving the Antioxidant Enzyme Activity and Biochemical Constituents in Capsicum Hybrids

Micronutrients, particularly Iron (Fe) and Zinc (Zn), play a vital role in the growth and development of plants due to their catalytic effect on many metabolic processes. However, the biochemical responses to the applied micronutrients vary with cultivars and their species. A screening experiment was conducted during 2020 to know the antioxidants enzyme activities and biochemical constituents in response to iron and zinc fertilization by six capsicum hybrids grown in grow bags under shade net conditions. The experiment consists of three treatments viz., Control (No Fe & Zn), 50 kg FeSO4 and 37.5 kg ZnSO4 ha-1 as a basal soil application with six capsicum hybrids viz., Indra, Priyanka, Inspiration, Massilia, Bachata, and Local green. Leaf samples of the capsicum hybrids were collected at Fruiting stage and analysed for antioxidant enzyme activities. The fruit samples were used for quantifying the biochemical constituents. The results revealed that, application of ferrous sulphate (FeSO4) and zinc sulphate (ZnSO4) to capsicum hybrids increased the biochemical constituents in fruits and the antioxidant enzyme activities in leaves. Out of the six hybrids tested, Indra possessed higher ascorbic acid content (9.20 mg 100 g-1 fresh weight), acidity (6.0), and total soluble solids (6.10 Brix) in the fruits, which was followed by Inspiration and Bachata. The superoxide dismutase (6.70 unit’s mg-1 protein) and peroxidase (6.90 unit’s g-1 fresh weight) activities were also higher with the same genotypes. The biochemical constituents and antioxidant enzyme response to Zn addition was better than Fe. There was 13.2, 10.9 and 9.5 per cent increase in titratable acidity, total soluble solids, ascorbic acid content in the fruits of Indra due to ZnSO4 application.The Principal Component Analysis (PCA) and hierarchical clustering revealed that Indra is highly responsive to Zn and Fe fertilization, while the local green showed very less response. The rest of the genotypes such as Inspiration, Bachata, Massilia, and Priyanka, are medium responsive for Zn and Fe fertilization.

Climate change and tropical sponges: The effect of elevated pCO₂ and temperature on the sponge holobiont

<p>As atmospheric CO₂ concentrations rise, associated ocean warming (OW) and ocean acidification (OA) are predicted to cause declines in reef-building corals globally, shifting reefs from coral-dominated systems to those dominated by less sensitive species. Sponges are important structural and functional components of coral reef ecosystems, but despite increasing field-based evidence that sponges may be ‘winners’ in response to environmental degradation, our understanding of how they respond to the combined effects of OW and OA is limited. This PhD thesis explores the response of four abundant Great Barrier Reef species – the phototrophic Carteriospongia foliascens and Cymbastela coralliophila and the heterotrophic Stylissa flabelliformis and Rhopaloeides odorabile to OW and OA levels predicted for 2100, under two CO₂ Representative Concentration Pathways (RCPs). The overall aim of this research is to bridge gaps in our understanding of how these important coral reef organisms will respond to projected climate change, to begin to explore whether a sponge dominated state is a possible future trajectory for coral reefs. To determine the tolerance of adult sponges to climate change, these four species were exposed to OW and OA in the Australian Institute of Marine Science’s (AIMS) National Sea Simulator (SeaSim) in a 3-month experimental study. The first data chapter explores the physiological responses of these sponges to OW and OA to gain a broad understanding of sponge holobiont survival and functioning under these conditions. In this chapter I also address the hypothesis that phototrophic and heterotrophic sponges will exhibit differential responses to climate change. In the second and third data chapters I explore the cellular lipid and fatty acid composition of sponges, and how these biochemical constituents vary with OW and OA. Lipids and fatty acids are not only vital energy stores, they form the major components of cell membranes, and the structure and composition of these biochemical constituents ultimately determines the integrity and physiological competency of a cell. Therefore through these analyses I aimed to determine how OW and OA affects the metabolic balance of sponges, and to understand mechanisms underpinning observed systemic sponge responses. Finally, to provide greater insight into the population level impacts of climate change on tropical sponges, in the last data chapter I explore the response of the phototrophic species Carteriospongia foliascens to OW/OA throughout its developmental stages. I found that while sponges can generally tolerate climate change scenarios predicted under the RCP6.0 conditions for 2100 (30ºC/ pH 7.8), environmental projections for the end of this century under the RCP8.5 (31.5ºC/ pH 7.6) will have significant implications for their survival. Temperature effects were much stronger than OA effects for all species; however, phototrophic and heterotrophic species responded differently to OA. Elevated pCO₂ exacerbated temperature stress in heterotrophic sponges but somewhat ameliorated thermal stress in phototrophic species. Furthermore, sponges with siliceous spiculated skeletons resisted the RCP 8.5 conditions for longer than the aspiculate species. Biochemical analysis revealed that spiculated species also have greater cell membrane support features, which is likely to contribute to the observed stress tolerance. I also found that the additional energy available to phototrophic sponges under OA conditions may be used for investment into cell membrane support, providing protection against thermal stress. Finally, larval survival and settlement success of C. foliascens was unaffected by OW and OA treatments, and juvenile sponges exhibited greater tolerance than their adult counterparts, again with evidence that OA reduces OW stress for some of these life stages. Based on the species studied here, this thesis confirms that sponges are better able to deal with OW and OA levels predicted for 2100 under RCP6.0, compared to many corals for which survival in a high CO₂ world requires OW to remain below 1.5°C. This suggests sponges may be future ‘winners’ on coral reefs under global climate change. However, if CO₂ atm concentrations reach levels predicted under RCP8.5, the prognosis for sponge survival by the end of this century changes as inter-species sponge tolerances to OW and OA differ. Under this projection it is likely we will also start to see a shift in sponge populations to those dominated by phototrophic sponges with siliceous spiculated skeletons. Overall, this thesis gives a holistic view of OW and OA impacts on tropical sponges and provides the basis from which to explore the potential for a sponge-coral regime shift in a high CO₂ world.</p>

Climate change and tropical sponges: The effect of elevated pCO₂ and temperature on the sponge holobiont

<p>As atmospheric CO₂ concentrations rise, associated ocean warming (OW) and ocean acidification (OA) are predicted to cause declines in reef-building corals globally, shifting reefs from coral-dominated systems to those dominated by less sensitive species. Sponges are important structural and functional components of coral reef ecosystems, but despite increasing field-based evidence that sponges may be ‘winners’ in response to environmental degradation, our understanding of how they respond to the combined effects of OW and OA is limited. This PhD thesis explores the response of four abundant Great Barrier Reef species – the phototrophic Carteriospongia foliascens and Cymbastela coralliophila and the heterotrophic Stylissa flabelliformis and Rhopaloeides odorabile to OW and OA levels predicted for 2100, under two CO₂ Representative Concentration Pathways (RCPs). The overall aim of this research is to bridge gaps in our understanding of how these important coral reef organisms will respond to projected climate change, to begin to explore whether a sponge dominated state is a possible future trajectory for coral reefs. To determine the tolerance of adult sponges to climate change, these four species were exposed to OW and OA in the Australian Institute of Marine Science’s (AIMS) National Sea Simulator (SeaSim) in a 3-month experimental study. The first data chapter explores the physiological responses of these sponges to OW and OA to gain a broad understanding of sponge holobiont survival and functioning under these conditions. In this chapter I also address the hypothesis that phototrophic and heterotrophic sponges will exhibit differential responses to climate change. In the second and third data chapters I explore the cellular lipid and fatty acid composition of sponges, and how these biochemical constituents vary with OW and OA. Lipids and fatty acids are not only vital energy stores, they form the major components of cell membranes, and the structure and composition of these biochemical constituents ultimately determines the integrity and physiological competency of a cell. Therefore through these analyses I aimed to determine how OW and OA affects the metabolic balance of sponges, and to understand mechanisms underpinning observed systemic sponge responses. Finally, to provide greater insight into the population level impacts of climate change on tropical sponges, in the last data chapter I explore the response of the phototrophic species Carteriospongia foliascens to OW/OA throughout its developmental stages. I found that while sponges can generally tolerate climate change scenarios predicted under the RCP6.0 conditions for 2100 (30ºC/ pH 7.8), environmental projections for the end of this century under the RCP8.5 (31.5ºC/ pH 7.6) will have significant implications for their survival. Temperature effects were much stronger than OA effects for all species; however, phototrophic and heterotrophic species responded differently to OA. Elevated pCO₂ exacerbated temperature stress in heterotrophic sponges but somewhat ameliorated thermal stress in phototrophic species. Furthermore, sponges with siliceous spiculated skeletons resisted the RCP 8.5 conditions for longer than the aspiculate species. Biochemical analysis revealed that spiculated species also have greater cell membrane support features, which is likely to contribute to the observed stress tolerance. I also found that the additional energy available to phototrophic sponges under OA conditions may be used for investment into cell membrane support, providing protection against thermal stress. Finally, larval survival and settlement success of C. foliascens was unaffected by OW and OA treatments, and juvenile sponges exhibited greater tolerance than their adult counterparts, again with evidence that OA reduces OW stress for some of these life stages. Based on the species studied here, this thesis confirms that sponges are better able to deal with OW and OA levels predicted for 2100 under RCP6.0, compared to many corals for which survival in a high CO₂ world requires OW to remain below 1.5°C. This suggests sponges may be future ‘winners’ on coral reefs under global climate change. However, if CO₂ atm concentrations reach levels predicted under RCP8.5, the prognosis for sponge survival by the end of this century changes as inter-species sponge tolerances to OW and OA differ. Under this projection it is likely we will also start to see a shift in sponge populations to those dominated by phototrophic sponges with siliceous spiculated skeletons. Overall, this thesis gives a holistic view of OW and OA impacts on tropical sponges and provides the basis from which to explore the potential for a sponge-coral regime shift in a high CO₂ world.</p>

Growth, mineral uptake, chlorophyll content, biochemical constituents and non-enzymatic antioxidant compounds of white pepper (Piper nigrum L.) grown under saline conditions

Salinity stress is the main abiotic constraints limiting crop yield worldwide. We investigated the effect of salt stress on growth, dry weight partitioning, chlorophyll content, mineral uptake, biochemical constituents and non-enzymatic antioxidant compounds of white pepper (Piper nigrum L.). White pepper seeds were planted in polythene bags previously filled with sand and supplied with a nutrient solution in a greenhouse during six weeks as a completely randomized design. Plants were subjected to four different concentrations of NaCl (0, 50, 100 and 200 mM). Supplies of intake doses of NaCl in the culture medium significantly decreased the dry biomass, stem height, leaf area and chlorophyll contents respectively from 100 mM NaCl. Mineral elements (K, Ca and Mg) significantly (P < 0.001) decreased in plant organs. The different biochemical constituents (proline, total soluble carbohydrates, soluble proteins and total free amino acids), total phenolic and flavonoids contents significantly (P < 0.001) increased from 50 mM NaCl. The accumulation of biochemical constituents in the leaves increased the osmotic potential of white pepper and could be considered as biochemical indicators of early selection and osmotic adjustment ability for salt tolerant plants. The planting of white pepper in salt affected soils could be encouraged for better development.

Morphological and Biochemical Constituents Influencing Aphids and Whiteflies Tolerance in Tomato Genotypes

Effects of morphological and biochemical constituents on the population of sucking insect pests infesting tomato plant were evaluated. Among the twenty genotypes evaluated under field condition at different seasons (summer, kharif, rabi), it revealed that the genotypes namely BRDT-1, EC 620421, Solanum peruvianum, EC 538455 and S. cheesmaniae had minimum number of aphid and whitefly population throughout all the three seasons due to their morphological traits like more trichome density and thick stem diameter as well as the presence of biochemical attributes like phenol and tannins which were present in those genotypes at higher concentration. The higher content of leaf chlorophyll had resistance effect against the population of aphid and whitefly, while total sugar content did not have any significant effect on resistance. Bangladesh J. Bot. 50(3): 483-489, 2021 (September)