Influence of physicochemical factors on water exchange in cotton leaves under the moisture deficit conditions

Presowing treatment of cotton seeds with a physical factor (low-frequency electromagnetic field - LF EMF) and a chemical compound (glycyrrhizic acid - GzA) and sowing them under conditions of optimal and limited water supply showed that different varieties of cotton, depending on their biological peculiarities and the method of seed treatment, had different parameters of water exchange in plants. The experiments were carried out in laboratory, greenhouse, lysimetric and field conditions, the indicators of the electrical resistance of leaf tissues (ERLT) of cotton plants depended on the conditions of water supply. According to this indicator, the varieties Ishonch, Gulbahor-2 and Navbahor-2 showed greater resistance to soil moisture deficiency, in comparison with the variety Tashkent-6. The plant varieties from seeds, treated with LF EMF and GzA, to a greater or lesser extent, are in the range with the lowest ERLT values, in comparison with the varieties from untreated seeds.

Study of morpho-biological characteristics of rice samples grown under conditions of insufficient and optimal water supply

The article shows the results of a morpho-biological study of rice cultivars grown in the fields of the Rostov Region under drought conditions and normal water supply. The aim of the research is a comparative structural analysis of rice samples under conditions of soil and air drought and under normal flooding with water. The formation of quantitative traits in plants under normal watering conditions and with a moisture deficit occurred in different ways. Under drought conditions, compared with the norm, the yield decreased (67.9% of the norm), the number of plants to be harvested per 1 m2, the mass of the panicle, the mass of 1000 grains; increased bushiness, the number of spikelets on the panicle and its density, the growing season “flooding with water – flowering”. The number of empty spikelets on a panicle and the percentage of empty grain increased especially strongly. The values of the remaining studied characteristics were at the same level in both variants of the experiment. The maximum yield in dry conditions was formed by the varieties Boyarin (4.43 t/ha), Contact (4.53 t/ha), Zolotye vshody (4.60 t/ha) and Sukhodol (4.60 t/ha). Drought-resistant forms that can be used to create dry-land rice varieties have been identified.

Hydrological and Meteorological Controls on Large Wildfire Ignition and Burned Area in Northern California during 2017–2020

This study examined the hydrological/meteorological controls on large wildfires > 10,000 acres (40.5 km2) during 2017–2020 in Northern California at spatial and temporal scales of the target wildfires’ occurrence or growth. This study used the following simple indices for analysis: Moisture Deficit Index (MDI) computed by dividing vapor pressure deficit by soil moisture, MDIWIND computed by multiplying MDI by horizontal wind speed, and MDIGUST computed by multiplying MDI by wind gust speed. The ignition location MDIWIND and MDIGUST showed larger values on the ignition date in fire-years compared to non-fire-years for most of the target wildfires (95.8% and 91.7%, respectively). The peak timing of MDIGUST, which is to evaluate the integrated effect of dry atmosphere/soil and windy condition, coincided with the ignition date for August Complex Fire 2020, Ranch Fire 2018, Claremont-Bear Fire 2020, and Camp Fire 2018. We also found that August Complex Fire 2020, Claremont-Bear Fire 2020, and Camp Fire 2018 occurred in the areas where MDIGUST became spatially and temporally high. Further, strong relationships were found between burned area sizes of the target wildfires and MDI (R = 0.62, p = 0.002), MDIWIND (R = 0.72, p < 0.001), and MDIGUST (R = 0.68, p < 0.001). Overall, the findings in this study implied the strong effect of dry atmosphere/soil and windy conditions on recent large wildfire activities in Northern California. The findings could contribute to a more temporally and spatially detailed forecast of wildfire risks or a better understanding of wildfires’ occurrence and growth mechanisms.

Drivers behind the summer 2010 wave train leading to Russian heatwave and Pakistan flooding

Summer 2010 saw two simultaneous extremes linked by an atmospheric wave train: a record-breaking heatwave in Russia and severe floods in Pakistan. Here, we study this wave event using a large ensemble climate model experiment. First, we show that the circulation in 2010 reflected a recurrent wave train connecting the heatwave and flooding events. Second, we show that the occurrence of the wave train is favored by three drivers: (1) 2010 sea surface temperature anomalies increase the probability of this wave train by a factor 2-to-4 relative to the model’s climatology, (2) early-summer soil moisture deficit in Russia not only increases the probability of local heatwaves, but also enhances rainfall extremes over Pakistan by forcing an atmospheric wave response, and (3) high-latitude land warming favors wave-train occurrence and therefore rainfall and heat extremes. These findings highlight the complexity and synergistic interactions between different drivers, reconciling some seemingly contradictory results from previous studies.

Siberian 2020 heatwave increased spring CO2 uptake but not annual CO2 uptake

Siberia experienced an unprecedented strong and persistent heatwave in winter to spring of 2020. Using bottom-up and top-down approaches, we evaluated seasonal and annual CO2 fluxes of 2020 in the northern hemisphere (north of 30ºN), focusing on Siberia where the pronounced heatwave occurred. We found that over Siberia, CO2 respiration loss in response to the pronounced positive winter temperature anomaly was greater than in previous years. However, continued warming in spring enhanced photosynthetic CO2 uptake, resulting in the largest seasonal transition in NEE, that is, the largest magnitude of the switch from the net CO2 loss in winter to net CO2 uptake in spring until June. However, this exceptional transition was followed by the largest reduction in CO2 uptake in late summer, due to multiple environmental constraints, including a soil moisture deficit. Despite a substantial increase of CO2 uptake by 22 ± 9 gC m-2 in spring in response to the heatwave, the mean annual CO2 uptake over Siberia was slightly lower (3 ± 13 gC m-2 year-1) than the average of the previous five years. These results highlight the highly dynamic response of seasonal carbon fluxes to extreme temperature anomalies at high latitudes, indicating a seasonal compensation between abnormal uptake and release of CO2 in response to extreme warmth that may limit carbon sink capacity in high northern latitudes.

Dependence of productivity of white lupine seeds on the foliar dressing with macro- and micronutrient fertilizers

The paper presents the results of the studies on the determination of the effect of foliar dressings with macro- and micronutrient fertilizers on linear growth, the mass of air-dry matter of plants, leaf surface, the formation of a symbiotic apparatus and the yield of seeds of white lupine (Lupinualbus L.) in the conditions of black soils of the Central Black Earth region of the Russian Federation. The field experiments were carried out in 2018-2020 at the Department of Crop production, Breeding and Horticulture of Belgorod State Agrarian University. The object of the research is a high-intensity variety of white Degas lupine. The subject of the research is microfertilizer Aquamix-TV, potassium sulfate fertilizer (K2SO4), phosphate-potassium monophosphate fertilizer (KH2PO4). The weather during the years of the experiments was hot and dry. During the critical periods of the development of lupine plants, a moisture deficit was observed with the excess of heat. The soil cover of the experimental site was represented by a typical medium-thick low-humus heavy loamy black soil with a granulometric composition. The accounting area of the plot was 18 m2, the replication was fourfold and the placement was systematic. The experiment included six variants: control (without fertilizers), foliar dressing with Aquamix-TV micronutrient fertilizer, foliar dressing with potassium sulfate solution, foliar dressing with potassium monophosphate solution, foliar dressing with Aquamix-TV + potassium sulfate mixture and foliar dressing with Aquamix-TV + monophosphate mixture potassium. The analysis of the obtained data showed that the highest yield of seeds of white lupine variety Dega was obtained on variants with foliar dressing with micronutrient fertilizer Aquamix-TV in combination with potassium sulfate and monopotassium phosphate, which amounted to 3.52 and 3.51 t / ha, respectively, which is 0.52 and 0.51 t / ha or 17.3 and 17.1% more than the control variant.

The effect of tillering on spring wheat productivity in various agro-weather conditions

The current study was carried out on the basis of the Institute of Seed Production and Agrotechnologies, located in the Ryazan Region in 2010–2019, in order to determine the participation share of tillering shoots in the formation of spring wheat productivity in various agro-weather conditions. The objects of the study were the varieties ‘Lada’, ‘Agata’, ‘RIMA’, ‘Maestro’ developed by the Federal Research Agro-Engineering Center VIM. The mean productivity of the studied spring wheat varieties, depending on the level of moisture supply of the growing seasons, had a significant range of 2.20–5.29 t/ha. The mean density of the stems varied from 216 to 620 pcs/m2 among the varieties. The minimum value of 153–253 pcs/m2 was formed under severe drought conditions. When moisture supply improved, the indicator sharply increased in 2.6 times. There has been established that in more humid conditions (HThC 0.98–1.55) the plants were able to realize their potential tillering to a greater extent, the general indicators of tillering among the varieties ranged from 1.06 to 1.23 and 1.63 to 2.11. There was estimated an effect of secondary shoots on productivity, which was 35.2% on average in the trial, and from 10.6% to 48.3% depending on the genotype and environmental conditions. There has been found a shoot formation decrease in 2.4 times of the variety ‘Lada’ under a moisture deficit. There has been determined that the variety ‘RIMA’ had the lowest tillering coefficient for all vegetation periods, and grain weight per a main spike mainly contributed to its productivity. During the moisture deficit periods, the share of the effect of lateral shoots in the variety ‘Agata’ was at the level of mean values, and on 9.9% and 13.1% more than in the varieties ‘Lada’ and ‘RIMA’, respectively. The maximum value of the productivity on the lateral shoots was formed by the variety ‘Maestro’, the productivity share of the secondary shoots during all periods was higher than that of all varieties and amounted to 39.1–48.3%.

Establishment of a Standard Micropropagation Protocol for the Production of Uniform Planting Material in Musa Laterita (Section: Rhodochlamys).

Musa laterita is one of the dwarf statured, ornamental Musa species, which belongs to the section Rhodochlamys. It is immune to Sigatoka leaf spot and Fusarium wilt diseases and also exhibits tolerance to moisture deficit stress. Among the fungal diseases, fusarium wilt especially race TR4 is highly threatening the banana industry worldwide and hence the TR4 resistant gene should be identified on priority for use in banana improvement programmes. Though, it is a wild seeded type which can be easily propagated through seeds, the off springs are not genetically uniform making it unfit for any molecular analysis. In vitro micro propagation of ornamental banana including Musa laterita is limited due to poor multiplication rates compared to commercial cultivars. Therefore, the present study was undertaken to establish an in vitro protocol for plant regeneration from shoot tip explants. Efforts were made to enhance the multiplication efficiency using MS media fortified with BAP, TDZ, NAA, IAA and IBA in different combinations so as to obtain maximum numbers of plantlets in minimum duration. The plantlets produced would be used to study the molecular mechanism behind Fusarium wilt resistance (TR4), through transcriptome analysis.