In vivo screening of salinity tolerance in giant swamp taro (Cyrtosperma merkusii)

Giant Swamp Taro (Cyrtosperma merkusii) is a staple food crop in the Pacific, especially in the low lying atoll islands such as Tuvalu and Kiribati. This is owing to its ability to survive under poor soil conditions and harsh environments. However, as a result of the effects of climate change such as sea water inundation and intrusion into the fresh ground water lens, this crop is now under threat. To address this issue an adaption approach was taken whereby, Cyrtosperma merkusii was screened in vivo for salt tolerance. The epistemology followed random selection of two cultivars Ikaraoi and Katutu. These two cultivars were subjected to 0% (0 parts per trillion), 0.5% (5 ppt), 1% (10 ppt), 1.5% (15 ppt) and 2% (20 ppt) of salt in Yates’s advance seedling common potting mix. Both cultivars were able to tolerate salinity levels up-to 5ppt which is significantly more than the salt tolerance in glycophytes of 2.83 ppt. This research provides an insight into the variation of salt tolerance that may exist in C.merkusii gene pool, which can be used to adapt to natural disasters and buffer its impacts

A descriptor list for giant swamp taro (Cyrtosperma merkusii) and its cultivars in the Federated States of Micronesia

Atoll islands are the diversity hot spots for Cyrtosperma merkusii (giant swamp taro) and its traditional knowledge, especially in the Federated States of Micronesia (FSM). In these atolls and islands the giant aroid is given high importance in the food, cultural and traditional systems. Despite this, a significant lack of knowledge and threat of salt water intrusion in the face of climate change exists for the aroid. To curb this issue a classification descriptor list using the taro descriptors(1999) and traditional knowledge of the FSM farmers was developed. The descriptor list was then employed to classify the many cultivars present in FSM. The list consisted of 37 morphological traits divided into plant habit leaves, petiole,inflorescence, root, corm, taste and special characteristics. Using this descriptor list 40 distinct FSM cultivars was classified,four of which were unknown to the locals namely PF1, Semesrao, Liha mwahu and Nah. The results of the classification provided some knowledge of the various cultivars and also showed that diversity did exist within the gene pool of the aroid. With further research and documentation the diversity that exist within the gene pool of the aroid can be explored and utilized to buffer the impacts of salt water intrusion, while onserving the aroid and building its knowledge base

Rapid screening methodology for salt tolerance in giant swamp taro (Cyrtosperma merkusii) and its diversity

Low-lying islands in the Pacific, such as atolls, are observing increased groundwater salinity, attributed to the impact of climate change, which is affecting the production of giant swamp taro (Cyrtosperma merkusii). Giant swamp taro has been cultivated successfully in the atolls providing food and nutritional security for atoll communities. In addition, this unique crop has high cultural status. Despite the importance of this crop to the atoll communities and the Pacific in general very little research has been carried out on this species. Little is known about the extent of diversity and any variability in salinity tolerance that might exist. To better understand whether or not salinity tolerance exists within the genepool of swamp taro and the extent to which it might vary, a rapid screening method is needed. This paper reports on the diversity in the Pacific with specific reference to the island of Tuvalu. It also describes an in vitro screening method, which assesses the impact of salinity levels of 0, 0.5, 1.5 and 2% salt on two cultivars from Kiribati, ‘Ika raoi’ (larger cultivar) and the ‘Katutu’ (smaller cultivar). Two approaches are discussed, one in which “saltwater” is applied on an increment basis to avoid shock to the plant, and to mimic, as much as possible, inundation; the other incorporates the salt directly into the culture medium. The criteria for monitoring the experiment include biomass measurements and visual toxicity responses. Plants showed high tolerance to salinity in the first four weeks of the experiment but exhibited slight toxicity from the fifth week

A rapid salt tolerance screening methodology for giant swamp taro (Cyrtosperma merkusii) and its diversity

Low¬lying islands in the Pacific such as atolls are observing increased groundwater salinity, attributed to the impact of climate change, which is affecting the production of Giant swamp taro (Cyrtosperma merkusii). Giant swamp taro has been cultivated successfully in the atolls providing food and nutritional security for atoll communities. In addition, this unique crop has high cultural status. Despite the importance of this crop to the atoll communities and the Pacific in general very little research has been carried out on this species. Little is known about the extent of diversity and any variability in salinity tolerance that might exist. To better understand whether or not salinity tolerance exists within the genepool of swamp taro and the extent to which it might vary, a rapid screening method is needed. This paper reports on the diversity in the Pacific with specific reference to the island of Tuvalu. It also describes an in vitro screening method, which assesses the impact of salinity levels of 0, 0.5, 1.5 and 2% salt on two cultivars from Kiribati, Ika raoi (larger variety) and the Katutu (smaller variety). Two approaches are discussed, one in which “saltwater” is applied on an increment basis to avoid shock to the plant, and to mimic, as much as possible, inundation; the other incorporates the salt directly into the culture medium. The criteria for monitoring the experiment include biomass measurements and visual toxicity responses. Plants showed high tolerance to salinity in the first four weeks of the experiment but exhibited slight toxicity from the fifth week

Apoptosis Induction Pathway in Human Colorectal Cancer Cell Line SW480 Exposed to Cereal Phenolic Extracts

Cereal phenolic extracts have previously been investigated for their potential anticancer properties; however, the exact mechanisms involved in the inhibition of tumour growth are unclear. One possible mechanism is the induction of apoptosis which is characterised by cell shrinkage, protein fragmentation, and DNA degradation followed by rapid engulfment of cell debris by macrophages. This study examines the ability of phenolic extracts from four cereals: rice, barley, oats and sorghum to induce apoptosis on colorectal cancer cells SW480. Wholegrain extracts from pigmented varieties of red rice, purple rice, black sorghum, and brown sorghum showed a significant reduction in cancer cell proliferation. Morphological observation using APOPercentage™ dye indicated positive for apoptosis. Further analyses of Yunlu29 (rice), Shawaya Short Black 1 and IS1136 (sorghum) showed expression of p53 and confirmed activation of multiple caspases, specifically for caspase 3 and 7. Purple rice, on the other hand, did not upregulate caspase 3 and 7, hence, suggestive of cell cycle arrest. Therefore, phenolic compounds present in cereals such as pigmented rice and sorghum may suppress cancer cell proliferation through the activation of the apoptosis

Inhibitory Effects of Pulse Bioactive Compounds on Cancer Development Pathways

Previous studies suggest that pulses may have the potential to protect against cancer development by inhibiting pathways that result in the development of cancer. These pathways include those that result in inflammation, DNA damage, cell proliferation, and metastasis. Other studies have demonstrated extracts from pulses have the capacity to induce apoptosis specifically in cancer cells. Compounds reported to be responsible for these activities have included phenolic compounds, proteins and short chain fatty acids. The majority of the studies have been undertaken using in vitro cell culture models, however, there are a small number of in vivo studies that support the hypothesis that pulse consumption may inhibit cancer development. This review highlights the potential benefit of a diet rich in pulse bioactive compounds by exploring the anti-cancer properties of its polyphenols, proteins and short chain fatty acids

Pulse Root Ideotype for Water Stress in Temperate Cropping System

Pulses are a key component of crop production systems in Southern Australia due to their rotational benefits and potential profit margins. However, cultivation in temperate cropping systems such as that of Southern Australia is limited by low soil water availability and subsoil constraints. This limitation of soil water is compounded by the irregular rainfall, resulting in the absence of plant available water at depth. An increase in the productivity of key pulses and expansion into environments and soil types traditionally considered marginal for their growth will require improved use of the limited soil water and adaptation to sub soil constrains. Roots serve as the interface between soil constraints and the whole plant. Changes in root system architecture (RSA) can be utilised as an adaptive strategy in achieving yield potential under limited rainfall, heterogenous distribution of resources and other soil-based constraints. The existing literature has identified a “‘Steep, Deep and Cheap” root ideotype as a preferred RSA. However, this idiotype is not efficient in a temperate system where plant available water is limited at depth. In addition, this root ideotype and other root architectural studies have focused on cereal crops, which have different structures and growth patterns to pulses due to their monocotyledonous nature and determinant growth habit. The paucity of pulse-specific root architectural studies warrants further investigations into pulse RSA, which should be combined with an examination of the existing variability of known genetic traits so as to develop strategies to alleviate production constraints through either tolerance or avoidance mechanisms. This review proposes a new model of root system architecture of “Wide, Shallow and Fine” roots based on pulse roots in temperate cropping systems. The proposed ideotype has, in addition to other root traits, a root density concentrated in the upper soil layers to capture in-season rainfall before it is lost due to evaporation. The review highlights the potential to achieve this in key pulse crops including chickpea, lentil, faba bean, field pea and lupin. Where possible, comparisons to determinate crops such as cereals have also been made. The review identifies the key root traits that have shown a degree of adaptation via tolerance or avoidance to water stress and documents the current known variability that exists in and amongst pulse crops setting priorities for future research

Changes in anthocyanin and antioxidant contents during maturation of Australian highbush blueberry (Vaccinium corymbosum L.) cultivars

The Australian blueberry industry is worth over $300 million, but there is limited information on factors influencing their chemical composition, particularly their ripeness and harvest stage. This pilot study investigated changes in total monomeric anthocyanin content (TMAC; measured using the pH-differential method) and total antioxidant capacity (TAC; measured with the cupric reducing antioxidant capacity assay) of four Australian highbush blueberry cultivars (Denise, Blue Rose, Brigitta and Bluecrop) at four time points and three maturity stages (unripe, moderately ripe and fully ripe). The TAC of most cultivars decreased by 8–18% during ripening, although that of the Blue Rose cultivar increased markedly. However, the TAC of ripe fruit from this cultivar also fluctuated markedly throughout the harvest season (between 1168–2171 mg Trolox equivalents 100 g−1). The TMAC increased sharply between the medium-ripe and fully ripe maturity stages, with the Blue Rose cultivar showing the highest TMAC values (211 mg 100 g−1, compared to 107–143 mg 100 g−1 for the remaining varieties). The TMAC of ripe fruit from this cultivar also rose steadily throughout the harvest season, in contrast to most other cultivars where the TMAC fell slightly over time. These results indicate that the levels of health-benefitting compounds in Australian-grown highbush blueberries may depend not only on the cultivar, but also upon the time of harvest