Iron is an essential micronutrient for almost all living organisms because of it plays critical role in metabolic processes such as DNA synthesis, respiration, and photosynthesis. Further, many metabolic pathways are activated by iron, and it is a prosthetic group constituent of many enzymes. An imbalance between the solubility of iron in soil and the demand for iron by the plant are the primary causes of iron chlorosis. Although abundant in most well-aerated soils, the biological activity of iron is low because it primarily forms highly insoluble ferric compounds at neutral pH levels. Iron plays a significant role in various physiological and biochemical pathways in plants. It serves as a component of many vital enzymes such as cytochromes of the electron transport chain, and it is thus required for a wide range of biological functions. In plants, iron is involved in the synthesis of chlorophyll, and it is essential for the maintenance of chloroplast structure and function. There are seven transgenic approaches and combinations, which can be used to increase the concentration of iron in rice seeds. The first approach involves enhancing iron accumulation in rice seeds by expressing the ferritin gene under the control of endosperm-specific promoters. The second approach is to increase iron concentrations in rice through overexpression of the nicotianamine synthase gene (NAS). Nicotianamine, which is a chelator of metal cations, such as Fe+2 and zinc (Zn+2), is biosynthesized from methionine via S-adenosyl methionine synthase. The third approach is to increase iron concentrations in rice and to enhance iron influx to seeds by expressing the Fe+2- nicotianamine transporter gene OsYSL2. The fourth approach to iron biofortification involves enhancing iron uptake and translocation by introducing genes responsible for biosynthesis of mugineic acid family phytosiderophores (MAs). The fifth approach to enhance iron uptake from soil is the over expression of the OsIRT1 or OsYSL15 iron transporter genes. The sixth approach to enhanced iron uptake and translocation is overexpression of the iron homeostasis-related transcription factor OsIRO2. OsIRO2 is responsible for the regulation of key genes involved in MAs-related iron uptake. The seventh approach to enhanced iron translocation from flag leaves to seeds utilizes the knockdown of the vacuolar iron transporter gene OsVIT1 or OsVIT2. The present review discusses iron toxicity in plants with regard to plant growth and metabolism, metal interaction, iron-acquisition mechanisms, biofortification of iron, plant-iron homeostasis, gene function in crop improvement, and micronutrient interactions.
Biodiversity affects human well-being and represents an essential determinant of ecosystem stability. However, the importance of below-ground biodiversity, and earthworm biodiversity in particular, has not received much attention. Earthworms represent the most important group of soil macrofauna. They play a crucial role in various biological processes in soil, and affect ecosystem services such as soil health and productivity, water regulation, restoration of degraded lands, and the balance of greenhouse gases. Anthropogenic activities can lead to a rapid reduction or loss of earthworm diversity, and threaten ecosystem services as well as human well-being. Therefore, conservation of earthworm diversity should receive urgent attention. Farmers need to be made aware of the importance of earthworm diversity conservation and its benefits. Local ecological knowledge is required for communication between scientists and farmers; moreover, efficient strategies for earthworm diversity conservation need to be developed. This paper intends to communicate the importance of earthworm diversity conservation. Development of conservation management to prevent earthworm diversity decline should be done wisely and involve all stakeholders.
Ornamental plants such as cut flowers and potted plants are traded around the world. In Japanese cut flower markets, flowers for business purposes and traditional flower arrangement classes are decreasing, while those for gifts and household use are increasing. There has been an increasing import of flowers from Malaysia, China, Columbia and other countries. The Netherlands occupies more than half of the worldwide exports of flowers. Postharvest technology is necessary to reduce the loss and provide consumers with high-quality flowers. There are many factors involved in senescence of cut flowers, including ethylene, water relation, soluble carbohydrate level, oxidative stress and programmed cell death. Ethylene inhibitors like STS and 1-MCP can inhibit ethylene actions and prolong the vase life of ethylene-sensitive flowers. The treatment of sugar and germicide improves carbohydrate level and water relation of cut flowers, resulting in prolonging their vase life. Physiology of cut flowers has been discussed and several methods of extending the vase life were introduced.
Reactive oxygen species accumulation has an established role in aging-related diseases, particularly in neurodegenerative diseases; however, its role remains incompletely elucidated. Considering the increasing elderly population, especially in developed countries, proper management of aging-related diseases has become essential and, research on antioxidant therapies is flourishing. Neuronal cells are at the center of oxidative stress research, where studies are being conducted to develop preventive or curative treatments against neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease. A panel of pro-oxidants can be used to induce oxidative damage in neuronal cells in vitro. In this mini-review, the use of hydrogen peroxide and 2,2′- azobis (2-amidinopropane) dihydrochloride -generated peroxyl radicals to induce oxidative stress in neuronal cells is discussed.
Stream water temperature is a dominant parameter of stream ecosystems, which affects water quality and biogeochemical processes, as well as the growth, metabolism, and behavior of the resident organisms. Because of growing concern regarding global warming and the impact of anthropogenic activities on the environment, recent intensive research has been conducted to elucidate the factors that control stream water temperature. Here, we review those recent advances, particularly with regard to the atmospheric conditions, landscape characteristics, and anthropogenic factors that influence stream water temperature.
We are living during the most diverse period in the history of Earth's life and evolution. Approximately 1.75 million species have been described, and best estimates show on the total number of species range from 8 to 9 million. Meanwhile, current extinction rates are calculated to be 100 to 1000 times higher than ever recorded, without taking into account all the underestimates in the evaluation process. A mass extinction at this moment would devastate the earth's diversity at a level that is impossible to predict. Human activity is the only true cause behind this crisis, thus are responsible for halting the extinction trend. Non-representative numbers of threatened species and biased concepts towards common species or pristine ecosystems in conservation trend have limited the protection range, and reduced the speed and efficiency of conservation. In this review, these limitations are examined, and new conservation approaches are suggested, such as preserving biological diversity in human-managed landscapes (as in the study cases in Laos and northeast Thailand). To conclude, only a comprehensive strategy, with simultaneous approaches in all levels of diversity will lead to conservation success, and restrict the sixth mass extinction event.