Do Dipteryx alata Vogel seedlings recover the quality and the photosynthetic and antioxidant responses in the post-flooding?

Dipteryx alata Vogel is a tree species widely found in Cerrado, settling preferentially in well drained soils. Studies related to ecophysiology of D. alata may contribute to the decision making about using seedlings of this species in projects aimed at the recovery of degraded areas where seasonal flooding happens. This study aimed to assess the effects of flooding on photosynthetic and antioxidant metabolism and quality of D. alata seedlings cultivated or not under flooding during four assessment periods (0, 20, 40, and 60 days), followed by 100 days after the end of each assessment period (0+100, 20+100, 40+100, and 60+100 days), allowing verifying the potential for post-flooding recovery. Flooded plants showed lower photosynthetic efficiency than non-flooded plants, regardless of the periods of exposure. However, this efficiency was recovered in the post-flooding, with values similar to that of the non-flooded seedlings. Moreover, the damage to FV/FM was evidenced by an increase in the period of exposure to flooding, but recovery was also observed at this stage of the photosynthetic metabolism. Seedling quality decreased under flooding, not varying between periods of exposure, but remained lower although the increase observed in the post-flooding period, with no recovery after flooding. The occurrence of hypertrophied lenticels associated with physiological changes and an efficient antioxidant enzyme system might have contributed to the survival and recovery of these seedlings. Thus, this species is sensitive to flooding stress but capable of adjusting and recovering metabolic characteristics at 100 days after the suspension of the water stress, but with no recovery in seedling quality. Thus, we suggested plasticity under the cultivation condition and determined that the time of 100 days is not enough for the complete resumption of growth.

Floodwater Depth Causes Different Physiological Responses During Post-flooding in Willows

Willows are widely planted in areas under risk of flooding. The physiological responses of willows to flooding have been characterized, but little is known about their responses during the post-flooding period. After the end of the stress episode, plants may modify some traits to compensate for the biomass loss during flooding. The aim of this work was to analyze the post-flooding physiological responses of willow under two different depths of stagnant floodwater. Cuttings of Salix matsudana NZ692 clone were planted in pots in a greenhouse. The experiment started when the plants were 2 months old with the following treatments: Control plants (watered to field capacity); plants partially flooded 10 cm above soil level (F10) and plants partially flooded 40 cm above soil level (F40). The flooding episode lasted 35 days and was followed by a recovery period of 28 days (post-flooding period). After the flooding period, height, diameter and total biomass were higher in F10, while F40 plants showed an increase in plant adventitious root production and leaf nitrogen content. During the post-flooding period, the photosynthetic rate, nitrogen, chlorophyll and soluble sugar contents were significantly higher in leaves of F40 than in Control and F10 treatments. Stomatal conductance and specific leaf area were higher in the previously flooded plants compared to Control treatment. Plants from F10 treatments showed a higher growth in height, root-to-shoot ratio, and carbon isotope discrimination than F40, while the opposite occurred for growth in diameter, vessel size and leaf area. We conclude that depth of floodwater not only causes different responses during flooding, but that its effects are also present in the post-flooding recovery period, affecting the growth and physiology of willows once the stress episode has ended. Even when flooding impacted growth negatively in F40, in the post-flooding period these plants compensated by increasing the photosynthetic rate, plant leaf area and xylem vessel size. Willows endurance to flooding is the result of both responses during flooding, and plastic responses during post-flooding.

Budi daya Terapung Tanaman Sawi Hijau dengan Perbedaan Dosis Pupuk NPK, Ukuran Polibag, dan Waktu Pemupukan

Cultivation of mustards green on floating raft is one of alternative cultivations which is applied by traditional farmers during flooding period in Riparian Wetland. The cultivation will increase Cropping Index and farmer’s income. The objective of this research is to evaluate growth and yield of mustards green on floating cultivation with the application of different NPK doses, polybag sizes, and fertilization times to find cultivation of mustards green which effective and efficient. This research was conducted on October 2016–February 2017 in Jakabaring Facility (104°46’44” E; 3°01’35” S) and Kimia Hasil Pertanian (LKHP) Laboratory, Fakultas Pertanian, Universitas Sriwijaya, Palembang. This research consisted of two steps. The first experiment used a completely randomized design with four doses of NPK (16:16:16) namely 0 (control), 5, 10, and 15 g plant-1. The second experiment used a Split Plot Design consisted of two factors namely polybag size (A1 and A2) and fertilization time (F1, F2, and F3). The result of the first experiment showed that utilization three doses of NPK significantly increased shoot length, number of leaves, and fresh weight compared control. The second experiment showed that polybag size and fertilization time did not significantly affect growth and yield parameters. Utilization of 5 g plant-1 of NPK on 1 week after transplanting (WAT) which used polybag size of 30 x 30 cm on growing media consisted of soil, manure, and rice husk (1:1:1/v:v:v) produced an effective and efficient cultivation of mustards green. Keywords: fertilizing, floating cultivation, green mustard, NPK

Variability of seedling survival and growth of different black poplar (Populus nigra L.) clones in the floodplain conditions of the Great War Island

Black poplar (Popuius nigra L.) belongs to endangered species of Serbia that grow in wetlands. This research was conducted on the Great War Island, which is located at the confluence of the Sava and Danube rivers, in Belgrade. This research aimed to determine the survival rate and growth dynamics of seedlings of different black poplar clones in the first year after planting in the flood conditions of the Great War Island. Recording of surviving seedlings and measurements of heights and diameters were performed in 2019, firstly in the spring (April IB, 2019), the second time during the summer (July IS, 2019), after the flooding period, and the third time in the autumn (October 4,2019), at the end of the vegetation period. The results of descriptive statistics, one-way analysis of variance (One-Way ANOVA), and cluster analysis are presented in this paper. Based on the obtained results, the highest survival rate after the flooding period was recorded in clone number 9 (85.70%), in which 78.60% of seedlings survived at the end of the vegetation period. It can be stated that the seedlings of black poplar clone number 9, based on a high survival rate, have the potential to be used for afforestation of wetlands, such as the Great War Island. However, the seedlings of this clone showed significantly lower values of measured heights and diameters, compared to the seedlings of most clones and mostly the seedlings were damaged. On the other hand, seedlings of clone 3 were superior based on the mean values of heights and diameters, obtained after the measurements in all three periods, including the period after flooding. Seedlings of this clone had a satisfactory survival rate, but it was constantly declining. Clone number 1 showed the lowest results, both in terms of survival at the end of the vegetation period and in terms of mean heights and diameters of seedlings. When using this species, special attention should be paid to preserving the gene pool and avoiding the establishment of commercial monoclonal plantations, especially in protected areas such as the Landscape of Outstanding Features "Great War Island".

Impact of Spring Freshet Flooding and Summer Rainfall Flooding on the Water Quality of an Alpine Barrier Lake

Background: Barrier lakes, formed by river interception, are particularly influenced by the upstream river. As such, spring freshet flooding and summer rainfall flooding due to wet precipitation (e.g. snow and rainfall) may sharply increase the concentrations of nitrogen, phosphorous and carbon compounds in barrier lakes. Too much nutrients will lead to lake eutrophication. In this study, we used Lake Jingpo, the world’s second largest alpine barrier lake, to examine the impact of spring freshet flooding and summer rainfall flooding on its water quality by building a hydrodynamic water-quality model with MIKE 21. Results:The MIKE 21 HD hydrodynamic model and MIKE 21 AD convection and diffusion module were calibrated using meteorological data, hydrological data, and water quality data collected in 2018. All errors were in the acceptable range. According to model simulation results, the flow velocity in Lake Jingpo is generally weak (mostly lower than 0.015 m/s), but it increases to 0.045 m/s and above during spring freshet flooding (April–May) and summer rainfall flooding (August–September), which is much higher than in other months. The flow volume of its largest inflowing river reaches 4.81×108 m3, 29.77×108 m3, and 58.4×108 m3 during spring freshet flooding, summer rainfall flooding, and 30-year frequency rainfall flooding period, respectively. The longest diffusion distances from the lake mouth to the downstream way are 16.3 km, 33.1 km, and 43.6 km during the spring freshet flooding, summer rainfall flooding, and 30-year frequency rainfall flooding period, respectively. A larger amount of precipitation leads to longer diffusion distances and increased concentrations of total nitrogen (TN), total phosphorous (TP), chemical oxygen demand (CODMn), and ammonia-nitrogen (NH4-N) in the lake. Conclusions: The sudden increase in water volume during spring flooding and summer rainfall flooding led to the rapid spread of nutrients and pollutants carried by the water into the barrier lake, resulting in a deterioration of lake water quality. In addition to pollution source control measures, ecological restoration and the construction of a buffer system in the catchment are very important measures to effectively improve the buffer capacity of barrier lakes in light of spring freshet flooding and summer rainfall flooding.

Impact of Spring Freshet Flooding and Summer Rainfall Flooding on the Water Quality of an Alpine Barrier Lake

Background: Among the many types of lakes, the barrier lake attracts special attention. China’s Lake Jingpo is one of the world’s rare such alpine lakes. Spring freshet flooding and summer rainfall flooding are factors that significantly increase barrier lake instability while also impacting water quality. Results: This study constructed a hydrodynamic water-quality model to simulate the impacts of spring freshet flooding, summer rainfall flooding, and 30-year frequency rainfall flooding on the flow-field and water quality at Lake Jingpo. Results showed that the lake-area flow field was generally weak (mostly lower than 0.015 m/s), but spring freshet flooding in April and summer rainfall flooding in August-September increase flow velocities to 0.045 m/s and above, much higher than in other months. Mudanjiang is the largest river that enters Lake Jingpo. Its flow reaches 4.81×10 8 m 3 , 29.77×10 8 m 3 , and 58.4×10 8 m 3 during the spring freshet flooding, summer rainfall flooding and 30-year frequency rainfall flooding period, respectively. The longest diffusion distances were measured from the lake mouth to the point of impact; these were 16.3 km, 33.1km, and 43.6km for the above periods, respectively. Our research revealed that precipitation played an important role in seasonal water quality at Lake Jingpo, and larger amounts of precipitation, longer diffusion distances, and increased pollutant concentrations. Conclusions: Compared to the effects of the spring freshet flooding period, the summer rainfall flooding and 30-year frequency rainfall flooding period more significantly affected water quality at Lake Jingpo. There was more overall precipitation, longer diffusion distances, and increased pollutant concentrations in the lake area. Alpine barrier lake environments are very fragile, which need greater care efforts and more stringent measures to control pollution sources throughout entire catchment area.

Effect of Flooding Under the Gas Exchange of Cocoa Seedlings

Under flooding conditions, plants exhibit morphological and physiological characteristics that indicate that the plant is undergoing stress. In this sense, the objective of this work was to evaluate the gas exchange of cocoa (Theobroma cacao L.) seedlings submitted to different times of flooding. The study was carried out at the experimental farm of the Capixaba Institute for Research Technical Assistance and Rural Extension, in Linhares, North of the State of Espírito Santo, Brazil. The experimental design was completely randomized. The treatments consisted in the flooding of the seedlings on days 0 (without flooding), 1, 2, 4 and 8. The seedlings were evaluated for gas exchange by characteristics: liquid assimilation of CO2; stomatal conductance; transpiration rate; water use efficiency. The gas exchange of cocoa seedlings were influenced by the flooding period in which they were submitted with a decrease in the values liquid assimilation of CO2, stomatal conductance and transpiration rate after the fourth day of flooding, after this period the seedlings developed morphological modifications that allowed them to adapt the flooding conditions, improving the liquid assimilation of CO2.

Multi-Level Morphometric Characterization of Built-up Areas and Change Detection in Siberian Sub-Arctic Urban Area: Yakutsk

Recognition and characterization of built-up areas in the Siberian sub-Arctic urban territories of Yakutsk are dependent on two main factors: (1) the season (snow and ice from October to the end of April, the flooding period in May, and the summertime), which influences the accuracy of urban object detection, and (2) the urban structure, which influences the morphological recognition and characterization of built-up areas. In this study, high repetitiveness remote sensing Sentinel-2A and SPOT 6 high-resolution satellite images were combined to characterize and detect urban built-up areas over the city of Yakutsk. High temporal resolution of Sentinel-2A allows land use change detection and metric spatial resolution of SPOT 6 allows the characterization of built-up areas’ socioeconomic functions and uses.

Methane emission from a flooded rice field under pre-germinated system

ABSTRACT: Local greenhouse gas flow measurement studies have been encouraged at a global level as a subsidy for national and state inventories. This study aimed to evaluate the seasonal methane emission during the 2008/2009 harvest, from an irrigated rice plantation, under pre-germinated system, in the municipality of Tremembé, State of São Paulo, using the static chamber technique and gas chromatography. The study showed high seasonal emission of methane (CH4) for the studied area, probably due to the long flooding period. It was estimated the CH4 emission factor (6.2 kg CH4 ha-1 dia-1), the partial global warming potential (pGWP, 26.2 Mg CO2eq growing season-1 ha-1) and the yield-scaled pGWP (YpGWP, 3.9 kg CO2eq kg grain).