Genotype-dependent responses of chickpea to high temperature and moderately increased light.

Our aim was to understand how moderately increased light intensities influenced the response of chickpea to high temperature. Three chickpea genotypes (Acc#3, Acc#7 and Acc#8) were treated at control (26 °C and 300 µmol m-2 s-1 photosynthetic photon flux density/PPFD), high temperature (38 °C and 300 µmol m-2 s-1 PPFD), increased light intensity (26 °C and 600 µmol m-2 s-1 PPFD) and combination of increased light and temperature (38 °C and 600 µmol m-2 s-1 PPFD). The net photosynthetic rate (PN) of Acc#3 and Acc#8 significantly decreased at high temperature regardless of light intensity. The PN of all three genotypes at increased light intensity was significantly higher than that at high temperature. The intracellular CO2 concentration (Ci), stomatal conductance (gs) and transpiration rate (E) of Acc#3 and Acc#8 at increased light intensity with or without high temperature significantly decreased in comparison with control and individually high temperature treatment. The relative water content of Acc#3 at high temperature and the combination treatment decreased as compared with control. The relative water content of Acc#7 at control was higher than the other three treatments. The Fv/Fm (Maximum quantum efficiency of photosystem II) of leaves from the three genotypes at 38 °C were lower than at 26 °C regardless of light intensity. The high temperature decreased chlorophyll content in the lower bottom leaf of Acc#7 and Acc#8 than control. In conclusion, chickpeas showed a higher net photosynthetic rate at increased light intensity to withstand heat stress, which was genotype-dependent. Physiological responses of different chickpea genotypes to increased temperature and light intensity indicated that distinct responsive mechanism of photosynthesis. This study provides information on how chickpea respond to high temperature and increased light intensity, which will help us to improve chickpea to deal with future climate changes.

Shedding light on the presymbiontic phase of C. arietinum.

A complex network of symbiotic events between plants and bacteria allows the biosphere to exploit the atmospheric reservoir of molecular nitrogen. In seeds, a series of presymbiotic steps are already identified during imbibition, while interactions between the host and its symbiont begin in the early stages of germination. In the present study, a detailed analysis of the substances' complex delivered by Cicer arietinum seeds during imbibition showed a relevant presence of proteins and amino acids, which, except for cysteine, occurred with the whole proteinogenic pool. The imbibing solution was found to provide essential probiotic properties able to sustain the growth of the specific chickpea symbiont Mesorhizobium ciceri. Moreover, the imbibing solution, behaving as a complete medium, was found to be critically important for the symbiont's attraction, a fact this that is strictly related to the presence of the amino acids glycine, serine, and threonine. Here, the presence of these amino acids is constantly supported by the presence of the enzymes serine hydroxymethyltransferase and formyltetrahydrofolate deformylase, which are both involved in their biosynthesis. The reported findings are discussed in the light of the pivotal role played by the imbibing solution in attracting and sustaining symbiosis between the host and its symbiont.

On the relevance of thermophysical characterization in the microwave treatment of legumes.

This study is focused on the characterization of the thermal behavior and physical properties of the most consumed legumes in the daily diet such as beans, lentils and chickpeas. Because of a lack of information in the literature about the effect of microwave treatments on legumes, characterization protocols have been applied before and after subjecting them to microwave irradiation suitable for pest disinfestation. The effects of two different radiative treatments, one suitable for inactivating the infesting fauna and the other simulating uncontrolled treatments, characterized by very high temperatures, were tested. The impacts of microwave treatments on legumes, in terms of thermal behavior, germination capability, tannin and total polyphenol composition and other physical properties (water uptake capability, texture change, mineral losses), after typical soaking cooking processes, are also studied. The thermal properties of the examined legumes were found to be comparable for all samples. Similarly, no significant differences in antinutritional factors, polyphenol and tannin content among all samples were detected. From the structural point of view, samples exposed to high temperatures showed texture degradation and in turn, loss of mineral nutrients during soaking processes. Moreover, their germination capability was drastically reduced. These latter results highlighted why it is important to correctly perform the radiative microwave process in order to both ensure effective and safe disinfestation and avoid nutritional value loss and the worsening of physical properties.

Pre-sowing static magnetic field treatment for improving water and radiation use efficiency in chickpea (Cicer arietinum L.) under soil moisture stress.

Soil moisture stress during pod filling is a major constraint in production of chickpea (Cicer arietinum L.), a fundamentally dry land crop. We investigated effect of pre-sowing seed priming with static magnetic field (SMF) on alleviation of stress through improvement in radiation and water use efficiencies. Experiments were conducted under greenhouse and open field conditions with desi and kabuli genotypes. Seeds exposed to SMF (strength: 100 mT, exposure: 1 h) led to increase in root volume and surface area by 70% and 65%, respectively. This enabled the crop to utilize 60% higher moisture during the active growth period (78-118 days after sowing), when soil moisture became limiting. Both genotypes from treated seeds had better water utilization, biomass, and radiation use efficiencies (17%, 40%, and 26% over control). Seed pre-treatment with SMF could, therefore, be a viable option for chickpea to alleviate soil moisture stress in arid and semi-arid regions, helping in augmenting its production. It could be a viable option to improve growth and yield of chickpea under deficit soil moisture condition, as the selection and breeding program takes a decade before a tolerant variety is released. Bioelectromagnetics. 37:400-408, 2016. © 2016 Wiley Periodicals, Inc.

Phenotypical and biochemical characterisation of resistance for parasitic weed (Orobanche foetida Poir.) in radiation-mutagenised mutants of chickpea.

BACKGROUND: Some radiation-mutagenised chickpea mutants potentially resistant to the broomrape, Orobanche foetida Poir., were selected through field trials. The objectives of this work were to confirm resistance under artificial infestation, in pots and mini-rhizotron systems, and to determine the developmental stages of broomrape affected by resistance and the relevant resistance mechanisms induced by radiation mutagenesis. RESULTS: Among 30 mutants tested for resistance to O. foetida, five shared strong resistance in both pot experiments and mini-rhizotron systems. Resistance was not complete, but the few individuals that escaped resistance displayed high disorders of shoot development. Results demonstrated a 2-3-fold decrease in stimulatory activity of root exudates towards broomrape seed germination in resistant mutants in comparison with non-irradiated control plants and susceptible mutants. Resistance was associated with an induction of broomrape necrosis early during infection. When infested, most of the resistant mutants shared enhanced levels of soluble phenolic contents, phenylalanine ammonia lyase activity, guaiacol peroxidase activity and polyphenol oxidase activity, in addition to glutathione and notably ascorbate peroxidase gene expression in roots. CONCLUSION: Results confirmed enhanced resistance in chickpea radiation-mutagenised mutants, and demonstrated that resistance is based on alteration of root exudation, presumed cell-wall reinforcement and change in root oxidative status in response to infection. © 2016 Society of Chemical Industry.

Effects of gamma irradiation on chickpea seeds vis-a-vis total seed storage proteins, antioxidant activity and protein profiling.

The present work describes radiation—induced effects on seed composition vis—à—vis total seed proteins, antioxidant levels and protein profiling employing two dimensional gel electrophoresis (2D—GE) in kabuli and desi chickpea varities. Seeds were exposed to the radiation doses of 1,2,3,4 and 5 kGy. The total protein concentrations decreased and antioxidant levels were increased with increasing dose compared to control seed samples. Radiation induced effects were dose dependent to these seed parameters while it showed tolerance to 1 kGy dose. Increase in the dose was complimented with increase in antioxidant levels, like 5 kGy enhanced % scavenging activities in all the seed extracts. Precisely, the investigations reflected that the dose range from 2 to 5 kGy was effective for total seed storage proteins, as depicted quantitatively and qualitative 2D—GE means enhance antioxidant activities in vitro.

Isoflavone content and composition in chickpea (Cicer arietinum L.) sprouts germinated under different conditions.

The influence of different germination conditions on isoflavone contents in chickpea sprouts was investigated in this study. Chickpea sprouts were germinated under different experimental conditions, including germination in the dark (GD), in the light (GL), under ethanol stress (GE), or under salt stress (GS) in the dark. The results demonstrated that the isoflavone contents in chickpea sprouts germinated with these various conditions significantly increased (p<0.05) compared to those in untreated chickpea seeds. The maximum amount of total isoflavones was obtained from chickpea sprouts in the GL group on day 8. The contents of formononetin and biochanin A in this group were 154 and 130 times higher, respectively, than in untreated seeds and 1.2 times higher than in sprouts in the GD group. Moreover, the isoflavone contents of chickpea sprouts in the GE and GS groups were also higher (p<0.05) than those in the GD group. A solution of 3% ethanol and 0.03 mol/L salt seemed to be the most optimal for isoflavone production among the solutions selected for this study. Most of the isoflavone contents significantly increased (p<0.05), especially formononetin and biochanin A, while the genistein content decreased with germination. Ononin, pseudobaptigenin, and glycitein glucoside acetylated were only detected in germinated chickpeas. This finding could expand the potential for the development of chickpea sprouts as a functional food.

Exposure of seeds to static magnetic field enhances germination and early growth characteristics in chickpea (Cicer arietinum L.).

Seeds of chickpea (Cicer arietinum L.) were exposed in batches to static magnetic fields of strength from 0 to 250 mT in steps of 50 mT for 1-4 h in steps of 1 h for all fields. Results showed that magnetic field application enhanced seed performance in terms of laboratory germination, speed of germination, seedling length and seedling dry weight significantly compared to unexposed control. However, the response varied with field strength and duration of exposure without any particular trend. Among the various combinations of field strength and duration, 50 mT for 2 h, 100 mT for 1 h and 150 mT for 2 h exposures gave best results. Exposure of seeds to these three magnetic fields improved seed coat membrane integrity as it reduced the electrical conductivity of seed leachate. In soil, seeds exposed to these three treatments produced significantly increased seedling dry weights of 1-month-old plants. The root characteristics of the plants showed dramatic increase in root length, root surface area and root volume. The improved functional root parameters suggest that magnetically treated chickpea seeds may perform better under rainfed (un-irrigated) conditions where there is a restrictive soil moisture regime.

Studies the effects of low dose of gamma rays on the behaviour of chickpea under various conditions.

In this study, the irradiation effects spring chickpea seeds with low doses (0, 5, 10, 15, 20 and 25 Gy) of radioactive cobalt (60Co) gamma-rays, on the germination characteristics as well as on the root and shoot growth, are investigated. The effects of such irradiation doses on the relative water content and cell membrane stability following a water deficit, are also studied. The irradiated seeds kept their germination speed and capacity in Petri dishes. On Murashige and Skoog (MS) liquid medium, the dose of 15 Gy induced a significant improvement (nearly 20%) in root length as compared with the 0 Gy dose. Under glass house conditions, the root and shoot lengths and dry weights of plants grown from seeds irradiated with a dose of 15 Gy, are found to be improved at rates of 19 and 89%, respectively when compared with plants issued from non-irradiated seeds. The same irradiation dose allowed the plants subjected to a water deficit to maintain a better water level and a more stable cell membrane as compared to the control plants.

Radiation processing for elimination of Salmonella typhimurium from inoculated seeds used for sprout making in India and effect of irradiation on germination of seeds.

The effect of radiation processing on the germination of the sprout seeds mung (Phaseolus aureus), matki (Phaseolus aconitifolius), chana (Cicer arietinum), and vatana (Pisum sativum) in terms of percent germination, germination yield, sprout length, vitamin C content, and texture was investigated. Gradual decreases in the percent germination, germination yield, and sprout length with increases in radiation dose (0.5 to 2.0 kGy) were observed. Vitamin C content and texture remained unaffected for the seeds treated with doses of up to 2 kGy. To determine the efficacy of radiation treatment in elimination of foodborne pathogens, seeds inoculated with 4 log CFU/g of Salmonella Typhimurium were treated with radiation doses of 1 and 2 kGy. A reduction in counts of Salmonella Typhimurium in inoculated seeds after radiation treatment was observed. A radiation dose of 2 kGy resulted in the complete elimination of 4 log CFU/g of Salmonella Typhimurium from the inoculated seeds. However, on sprouting for 48 h, the count of Salmonella Typhimurium reached 8 log CFU/g for the control seeds and the seeds treated with a 1-kGy radiation dose. The aerobic plate counts for seeds were 2.0 to 2.6 log CFU/g, which were reduced to 0.9 to 1.2 log CFU/g on treatment with a 2-kGy radiation dose. On sprouting for 48 h, the aerobic plate count reached 8 log CFU/g for both the control and radiation-treated seeds. The study demonstrates that irradiation can control bacterial levels on seeds but not contamination introduced during posttreatment handling. Therefore, radiation processing of the final product (sprouts) is recommended, rather than of the seeds.