Antioxidant Enzyme Activities and Abiotic Stress Tolerance Relationship in Vegetable Crops

Climatic changes can cause serious reductions in yield and crop quality. Under the threat of climatic changes, one of the precautions to cope is selection and development of resistant vegetable genotypes to abiotic stresses. Several physiological and biochemical reactions and different tolerance levels can occur according to plant species. When plants are subjected to environmental stresses such as salinity, drought, temperature extremes, herbicide treatment and mineral deficiency, the balance between the production of reactive oxygen species (ROS) and the quenching activity of antioxidants is upset, often resulting in oxidative damage. Since activated oxygen species can disrupt normal metabolism through oxidative damage to lipids, protein and nucleic acids, plants possess a number of antioxidant enzymes that protect them from these cytotoxic effects. To control the level of ROS and to protect cells under stress conditions, plant tissues contain several enzymes for scavenging ROS. The high levels of antioxidative enzyme activities were determined in the tolerant genotypes of tomatoes, eggplant, peppers, cucumbers, melons, squash, beans, okra, etc. to several abiotic stress factors. Both the whole plant and in vitro callus culture experiments gave similar results. Antioxidant enzymes can be useful for screening to determine the tolerant and sensitive plant genotypes against abiotic stresses

Indução de divisão nuclear simétrica e estruturas multinucleadas em micrósporos de berinjela (Solanum melongena L.) cultivados in vitro

Uma modificação de um protocolo utilizado para induzir embriogênese a partir de micrósporos de tabaco foi testada em berinjela (Solanum melongena L.). Em tabaco, micrósporos uninucleados são submetidos a um tratamento de estresse em meio "B" contendo manitol a 33ºC por seis dias. Os micrósporos são então transferidos para um meio AT3 contendo maltose para as fases posteriores de desenvolvimento. Neste estudo, micrósporos uninucleados e binucleados tardios do cultivar de berinjela Bambino foram pré-cultivados em meio "B" e, posteriormente, incubados a 4ºC, 25ºC e 33ºC por dois dias. Após os pré-tratamentos, as culturas de micrósporos foram transferidas para o meio AT3 contendo maltose 0,25 M e mantidas a 25ºC no escuro. A presença de divisão simétrica e estruturas multinucleadas foram verificadas com coloração DAPI do núcleo após uma e duas semanas. Foram observadas divisões simétricas dos núcleos e estruturas multinucleadas somente em micrósporos uninucleados, pré-tratados a 33ºC por dois dias. A frequência de estruturas multinucleadas foi de 19,4% sob essas condições. Nós demonstramos que a berinjela responde ao protocolo modificado de tabaco para produção de divisões simétricas e estruturas multinucleadas. Esses resultados podem ser utilizados como base para uma completa adaptação do sistema de tabaco em berinjela.A modification of a protocol used to induce tobacco microspore embryogenesis was tested in eggplant (Solanum melongena L.). In tobacco, uninucleate microspores are subjected to stress treatment by culturing in mannitol containing "B" medium at 33ºC for six days. The microspores are then transferred to maltose containing AT3 medium for further development. In the experiment presented here late uninucleate and bi-nucleate microspores of the eggplant cultivar Bambino were pre-cultured in B medium and then incubated at +4ºC, 25ºC and 33ºC, respectively, for two days. After the pre-treatments, microspore cultures were transferred to AT3 medium containing 0.25 M maltose and maintained at 25ºC in the dark. Presence of symmetrical division and multinucleate structures was checked with DAPI staining of the nucleus after one and two weeks. Symmetrical division of the nucleus and multinucleate structures were observed only in uni-nucleate microspores pre-treated at 33ºC for two days. The frequency of multinucleate structures was 19.4% under these conditions. We demonstrated that eggplant is responsive to the modified tobacco protocol in the production of symmetrically division and multinucleate structures. These results may be used as a basis for adaptation fully of the tobacco system in eggplant

Development of Androgenesis Studies on Eggplant (<em>Solanum melongena</em> L.) in Turkey from Past to Present

Eggplant is one of the most widely cultivated vegetable species in the world and Turkey. The breeding of eggplant with high yields and quality is one of the important efforts in the seed sector today. Traditional breeding activities cannot respond quickly to market mobility. With the integration of dihaploidization methods into the breeding cycles, breeding programs have gained significant momentum. The most used haploidy technique in eggplant is the anther culture based on androgenesis, and its use in public and private sectors has become widespread in recent years. To date, the use of the isolated microspore culture technique as another androgenesis technique is limited; however, the studies are in progress in particular for indirect microspore embryogenesis. Genotype effect is one of the most decisive factors determining the success of androgenesis in eggplant. Also, the other factors such as nutrient medium content, types and concentrations of plant growth regulators, age and growing conditions of donor plants, determination of the appropriate microspore developmental stages, different pre-treatments, temperature shocks and incubation conditions are also effective on androgenesis success. In this review, it is aimed to provide information about the in vitro eggplant androgenesis studies, which have been carried out and are currently being conducted in Turkey

Responses of Some Melon (Cucumis sp.) Genotypes to Salt Stress

WOS: 000261499500012The aim of this research is to identify differences in salt tolerance of melon genotypes and the possibility of using plant biomass values and degree of ion accumulation of leaves to determine salt tolerance. In addition, the increase in MDA amount of leaves on salt stress was evaluated. 36 different genotypes were identified according to different parameters in respect to salt tolerance and susceptibility to salinity, correlation coefficients among these characters were determined, It was observed that salt damage in melons is probably the result of toxic effects of Na+ and Cl- ions and the genotypes having low amounts of these ions are more tolerant. Midyat, Besni and Semame varieties were determinad as salt tolerant melon genotypes; Ananas and Yuva melon cultivars were most sensitive to salt stress

Seed Germination and Development of Serapias vomeracea (Burm.fil.) Briq. ssp orientalis Greuter in Tissue Culture

Serapias vomeracea (Burm. fil.) Briq. ssp. orientalis Greuter plants were obtained via asymbiotic germination under in vitro conditions. For the germination of seeds, different doses of gibberellic acid (GA3) (0, 0.1 and 0.5 mg/L) were added into a basic nutrient media consisting of half-strength MS (1/2 MS), Van Waes and DeBergh (VW and DB), Knudson C and non-inorganic nitrogen Knudson C (KC-N). Cultures were incubated in darkness for the first 3 months and thereafter transferred to a light/dark photoperiod of 16:8. At the end of the third month, protocorm rates were identified. They were subcultured every 4 weeks and 1/2 MS medium was used as a transfer medium. The highest germination rate, protocorm rate and plant growth rate were obtained from the Knudson C medium. The germination rate and number of plantlets were affected negatively by adding GA3

Induction of symmetrical nucleus division and multi-nucleate structures in microspores of eggplant (Solanum melongena L.) cultured in vitro

A modification of a protocol used to induce tobacco microspore embryogenesis was tested in eggplant (Solanum melongena L.). In tobacco, uninucleate microspores are subjected to stress treatment by culturing in mannitol containing "B" medium at 33ºC for six days. The microspores are then transferred to maltose containing AT3 medium for further development. In the experiment presented here late uninucleate and bi-nucleate microspores of the eggplant cultivar Bambino were pre-cultured in B medium and then incubated at +4ºC, 25ºC and 33ºC, respectively, for two days. After the pre-treatments, microspore cultures were transferred to AT3 medium containing 0.25 M maltose and maintained at 25ºC in the dark. Presence of symmetrical division and multinucleate structures was checked with DAPI staining of the nucleus after one and two weeks. Symmetrical division of the nucleus and multinucleate structures were observed only in uni-nucleate microspores pre-treated at 33ºC for two days. The frequency of multinucleate structures was 19.4% under these conditions. We demonstrated that eggplant is responsive to the modified tobacco protocol in the production of symmetrically division and multinucleate structures. These results may be used as a basis for adaptation fully of the tobacco system in eggplant

Drought stress mitigation with humic acid in two Cucumis melo L. genotypes differ in their drought tolerance

Different responses of two melon (Cucumis melo L.) genotypes (Semame, drought and salt-tolerant and Ananas, drought and salt- sensitive) to drought stress with or without humic acid ( HA) treatment were studied. The experiment was carried out under greenhouse conditions. The experimental design was two factorial randomized block with 4 replicates. HA treatment increased the shoot fresh and dry weights and leaf area of both genotypes under drought stress. HA stimulated accumulation of K and Ca ions, chlorophyll (SPAD value) and antioxidant enzyme activity (superoxide dismutase-SOD, catalase-CAT and glutathione reductase-GR) in both genotypes. This effect was more clear in the Semame genotype than in Ananas. As a result, HA treatment has been proved to influence the ability of melon genotypes to cope with drought stress and to increase their tolerance