RESUMEN
The "Returning Farmland to Lakes" (RFTL) project began in China following the catastrophic 1998 floods. It aims to recover flood storage capacity and mitigate flood risk to agriculture and people. This flood adaptation strategy divides the floodplain into three types of restoration polders with different flood control levels (double restoration polders, single restoration polders, and storage polders) and polders for intensive production and living (nonrestoration polders). During the substantial flooding in the Poyang Lake Basin in 2020, the double and single restoration polders were operated for flood diversion for the first time since 1999. This event provided an opportunity to assess the effectiveness of the RFTL project. Using satellite observations of rice planting and flooding areas, we found that 86% of paddy rice areas (3,400 km2) in the basin were successfully protected due to the timely flood diversion into different levels of polders. Compared to 1998, the flooded rice areas decreased overall by 58% (18 to 92% in different types of polders). Thus, the RFTL project has enhanced regional agricultural resistance to floods. A more comprehensive assessment of the RFTL project, including other ecosystem services and functions, is necessary in the future for regional sustainable development.
RESUMEN
Flood resistance in rice is very important in weed control, as weeds cannot overcome deep water. At present, there are no released varieties in Russia that would meet these requirements. The creation of such varieties will reduce production costs and pesticide load on the ecosystem. The object of the study was second-generation rice hybrids obtained by crossing the best varieties for economically valuable traits with samples carrying genes for resistance to prolonged flooding with water. To create double rice haploids resistant to prolonged flooding, the anther culture method was used, followed by molecular genetic evaluation of dihaploids for the presence of genes for resistance to prolonged flooding. An estimate of the growth energy under deep flooding was carried out according to our own method. As a result of the cultivation of anthers, 130 androgenic regenerated plants were obtained in 14 hybrid combinations. In terms of responsiveness to neoplasms, 60% of the panicles showed a positive result, while the rest 40% did not demonstrate callus formation. In total, 30 green regenerative lines were obtained from four rice hybrids, differing in visual morphological assessment. Large genotypic differences between the samples were revealed. These lines carry long-term flood resistance genes and can be used in rice breeding programs using dihaploids. As a result of the assessment of the growth energy in a number of obtained samples, the potential for rapid elongation of the first leaves, overcoming a large layer of water and accumulation of vegetative mass, was revealed.
RESUMEN
Property-level flood risk adaptation (PLFRA) has received significant attention in recent years, as flood resilience has become increasingly important in flood risk management. Earlier studies have indicated that learning from flood experiences can affect flood risk perception and the adoption of PLFRA measures; however, it remains unclear whether and how this learning process can be affected by flood control infrastructure-specifically, the level of flood resistance it offers. This study attempts to answer the question: Do people living in environments with different levels of flood resistance learn different lessons from flood experience, manifested in flood risk perception and PLFRA? We present a comparative study of the rural village of Xinnongcun and the urban community of Nanhuyayuan in Central China. In-person interviews with a total of 34 local residents were conducted to understand how flood experiences affect flood risk perception and PLFRA. We find that learning from flood experiences in the highly flood-resistant environment (Nanhuyayuan) does not contribute to flood risk perception but further enhances flood resistance, whereas learning in a less flood-resistant environment (Xinnongcun) leads to a better understanding of flood risk and promotes PLFRA. We argue that flood resistance can affect the learning from flood experiences. High flood resistance can suppress PLFRA through a different learning process that involves learning inertia and path dependency. In the search for flood resilience, this begs society to re-examine the widespread assertion that both structural and nonstructural measures are important in flood risk management. Supplementary Information: The online version contains supplementary material available at 10.1007/s10584-022-03401-3.
RESUMEN
The Amazonian wild rice Oryza grandiglumis has two contrasting adaptation mechanisms to flooding submergence: a quiescence response to complete submergence at the seedling stage and an escape response based on internodal elongation to partial submergence at the mature stage. We investigated possible factors that trigger these responses. In stem segments excised from mature O. grandiglumis plants, complete submergence only slightly promoted internodal elongation with increased ethylene levels in the internodes, while partial submergence substantially promoted internodal elongation without increased ethylene levels in the internodes. Incubation of non-submerged stem segments under a continuous flow of humidified ethylene-free air promoted internodal elongation to the same extent as that observed for partially submerged segments. Applied ethylene had little effect on the internodal elongation of non-submerged segments irrespective of humidity conditions. These results indicate that the enhanced internodal elongation of submerged O. grandiglumis plants is not triggered by ethylene accumulated during submergence but by the moist surroundings provided by submergence. The growth of shoots in O. grandiglumis seedlings was not promoted by ethylene or complete submergence, as is the case in O. sativa cultivars possessing the submergence-tolerant gene SUB1A. However, because the genome of O. grandiglumis lacks the SUB1A gene, the quiescence response of O. grandiglumis seedlings to complete submergence may be regulated by a mechanism distinct from that involved in the response of submergence-tolerant O. sativa cultivars.
Asunto(s)
Adaptación Fisiológica/efectos de los fármacos , Etilenos/farmacología , Inundaciones , Oryza/fisiología , Adaptación Fisiológica/genética , Brasil , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos , Genes de Plantas , Giberelinas/farmacología , Oryza/efectos de los fármacos , Oryza/genética , Brotes de la Planta/efectos de los fármacos , Brotes de la Planta/crecimiento & desarrollo , Tallos de la Planta/efectos de los fármacos , Tallos de la Planta/crecimiento & desarrolloRESUMEN
Specimens of Rostrozetes foveolatus were obtained from two inundated forest areas ("várzea" and "igapó") and from two nonflooded secondary forests in the Central Amazon Region. The survival rates of their populations under submerged and nonsubmerged conditions were compared in laboratory conditions. The "igapó" population was sampled during three periods in 1992: before (February: litter nonsubmerged), in the beginning (April: litter submerged) and in the peak of the inundation phase (July: litter submerged). At "igapó", the animals survived better when submitted to nonsubmerged conditions, meaning that submersion is a stress factor. The same result did not occur at "várzea", signifying a better adaptation of this population to the submersion stress. The lowest flood resistance (27 days) was found in animals from "terra firme" secondary forest, away from the igapó. A considerable submersion resistance in the population sampled in the secondary forest, near the igapó forest, was comparable to the populations of the inundated areas and greater than the resistence at "terra-firme", far away from the "igapó". Animals sampled in February of 1996 (reared individually in plastic containers), from the flooded forests had significantly higher survival rates than those from secondary forests. Three situations in relation to the submersion period were registered: a) one of "várzea", with a more resistant population, b) one of "igapó", with a intermediate resistance and c) one of "terra-firme", away from the "igapó", with a lower resistant population. In twelve of the fifteen species studied, a high resistance to submersion was also registered.
Espécimens de Rostrozetes foveolatus foram obtidos de duas florestas inundáveis (várzea e igapó) e de duas florestas secundárias (terra firme) da Amazônia Central. As populações foram comparadas para a obtenção da taxa de sobrevivência em experimentos de laboratório nas condições submersas e não submersas. As coletas no igapó foram efetuadas em três períodos de 1992: antes (fevereiro: serapilheira não submersa), no início (abril: serapilheira submersa) e no pico da inundação (julho: serapilheira submersa). No igapó, os animais sobreviveram melhor em condição não submersa, significando que a submersão é um fator de estresse. O mesmo não ocorreu na várzea, indicando que esta população está melhor adaptada ao estresse da submersão. A menor resistência à submersão (27 dias) foi registrada nos animais de uma floresta secundária da terra firme, situada longe do igapó. Na população da terra firme próxima ao igapó, a resistência a submersão foi comparável à registrada para as populações das áreas inundáveis e maior do que a registrada em terra firme longe do igapó. Em experimentos com animais coletados em fevereiro de 1996 (mantidos individualmente em recipientes plásticos), as populações das florestas inundáveis tiveram taxa de sobrevivência significativamente maior em relação aos das florestas não inundáveis. Três situações foram registradas quanto a resistência à submersão: a) a da várzea, com população mais resistente, b) a do igapó, com uma população intermediária e c) a da terra-firme longe do igapó, com uma população menos resistente. Em doze das outras quinze espécies estudadas foi registrada alta resistência às condições de submersão.