Gesunde Pflanzen最新文献

Asia produces the majority of the world’s rice (Oryza sativa L.), one of the utmost vital fundamental food crops, with 90% of worldwide production. Because of increases in average temperature, climate change has a negative impact on rice yield. It is essential to develop such verities of rice that have potential to meet challenges of environmental changes like heat stress etc. This research was approved to investigate heat tolerance ability of rice genotypes on the basis of morpho-physiological attributes at the experimental field area of Islamia University of Bahawalpur. Using a randomized complete blocked design (RCBD) and two sets of plots (one in early sowing rice, other plot goes under late sowing rice condition) with five replications was applied to study 102 genotypes of rice under heat stress. The days to heading, days to maturity, no. of panicles, flag leaf area, grain weight per panicle, no. of grains per panicle, 1000 grain weight and grain yield per plant were positively correlated among themselves under both early sowing and late sowing conditions. Results revealed that, out of 14 principal components (PCs), the first five PCs were showed significant genetic variation under both conditions. The first five PCs displayed 71.1% and 68.9% total variance in the examined germplasm under early and late sowing locations respectively. Based on PCA, 05 heat-tolerant and five heat-susceptible genotypes were identified. There is a significant difference in all the studied rice morphological and physiological traits. Effect of high temperature (heat stress) was observed in both early (normal) and late sowing (heat stress) environments. As a result of these findings selection based on these qualities is not appropriate for heat tolerance. The best performing germplasm under heat stress can be a desirable genotype to generate high yield and used for future breeding programs and early sowing of rice genotypes recommended in this study will be effective for developing heat tolerant rice varieties.

Onion thrips, Thrips tabaci Lind. (Thysanoptera: Thripidae) is a major pest of onion worldwide. It damages onion, Allium cepa L., both directly and indirectly, which leads to significant output losses. In 2022, research was conducted in a private onion field in the Delta region, Egypt, to evaluate the efficacy of bioinsecticides and synthetic insecticides and to evaluate the efficacy of macro- and micronutrient in determining treatment effects on onion thrips populations.

Injury caused by onion thrips is often not severe enough to warrant the application of numerous pesticides to crops in the Delta region of Egypt. Spinosad (Tracer 24% SC) and spinetoram (Radiant 12% SC) were used as bioinsecticides, and Pyridalyl (Pleo 50% EC) was used as a synthetic insecticide for managing onion thrips populations. The greatest decrease in infestation was achieved by the application of the chemical insecticide (Pyridalyl) Pleo 50% EC and the bioinsecticide (Spinosad) Tracer 24% SC. The greatest decrease in infestation was achieved by the application of the micronutrient boron.

Phytoremediation techniques include phyto-de-salinization, phytodegradation, phytoextraction, phyto-filtering, and phyto-volatilation. The phytoremediation technique is considered a promising method to remediate saline soils. The study was conducted with two concentrations of saline soil (50 and 100 mM) with one control, followed by treatment of two isolates (Azospirillum brasilense and Pseudomonas fluorescence). The experiment was conducted in a randomized complete block design using two hybrids (Hysun-33 & Hysun-39). The inoculation of Azospirillum brasilense increased the total biomass production, flowering characteristics, and yield of sunflowers. The study parameter’s result showed that using plant growth-promoting rhizobacteria (PGPR) gives successful vegetative growth with good flowering characteristics and induced salt tolerance in sunflowers. So, bacterial isolate Azospirillum brasilense conformed to better vegetative growth and flowering than isolates of Pseudomonas fluorescence. There was an increase in antioxidants, e.g., catalase, peroxidase, ascorbate peroxidase, and proline content, and a decrease in hydrogen peroxide content of plants by inoculation of Azospirillum brasilense and Pseudomonas fluorescence. Decreased growth at higher salinity levels causes hyper-ionic and hyperosmotic stress and can lead to plant demise. From the results obtained, it could be recommended that Azospirillum brasilense be used to induce salt tolerance in sunflower (Helianthus annus L.) cv. “Hysun-33” under high salinity levels increases vegetative growth, flowering character, yield, and quality of sunflower.

Bio-fertilizers (BF) and amino acids (AA) improve plant growth by activating antioxidant enzymes and establishing a favorable metabolic environment to maintain physiological balance and drought stress mitigation. This experiment aimed to assess the influence of some BF and AA on peanuts (Arachis hypogaea L.) under drought stress. It was conducted during 2018–2019 as a split-split plot based on a randomized complete blocks design with three replications in the experimental field of the Agricultural and Natural Resources Research and Education Center of Guilan province, Rasht, Iran. Three irrigation regimes including irrigation after 75 (IR75), 100 (IR100), and 125 (IR125) mm evaporation from class A evaporation pan, four levels of BF including no application of bio-fertilizers as control (Z0), Arbuscular mycorrhiza (AM), Azospirillum brasilense (AB), Pseudomonas fluorescens (SF) and four levels of AA including no application of AA as control (Z0), Aminol-Forte (AF), Humi-Forte (HF) and Pro-Amin (PA) comprised experimental treatments as main plot, sub-plot and sub-sub plot, respectively. Peanut seed yield (SY) decreased under intensive drought stress. In 2018 and 2019, peanut SY increased by 43.34 and 38.08% in IR75 compared to control, under the interaction of AB×HF and SF×HF, respectively. The interaction of AB and HF increased antioxidant enzymes and improved SY under drought stress, which can be considered an innovation. Hence, the application of AB and HF could be recommended to enhance peanut SY under similar climatic conditions.

A study assessed the potential for using cumulative growing degree days (CGDD) to predict the weed emergence periodicity of three weed species: Argemone mexicana, Brassica tournefortii, and Rapistrum rugosum. Weed emergence was monitored regularly by placing 200 fresh seeds of each weed species on the soil surface. Weed emergence data was fit using a three-parameter sigmoidal Gompertz model. The CGDD required for 50% emergence of A. mexicana ranged from 3380 to 5302, depending upon the seasonal variation in temperature and rainfall. The majority of emergence appeared from March to June. The seeds of A. mexicana exhibited dormancy, as the majority of seeds germinated in the second season. The CGDD required for 50% emergence of B. tournefortii ranged from 824 to 2311, depending upon the seasonal variation in temperature and intensity of rainfall. Most cohorts of B. tournefortii appeared in the first season from February to June, indicating little dormancy in seeds. The CGDD required for 50% emergence of R. rugosum ranged from 2242 to 2699, depending upon weather parameters (temperature and rainfall). The main cohorts of R. rugosum appeared from February to June, and 60% of seeds germinated in the first season, while 40% germinated in the second season, indicating dormancy in seeds. The coefficients of determination for the model verification on the emergence pattern of three weeds were > 85%, suggesting that CGDD are good predictors for the emergence of these weeds. These results suggest that forecasting the emergence of three weed species on the basis of CGDD and rainfall patterns will help growers to make better weed management decisions.

Cotton is a highly sensitive crop to drought stress. Consequently, it is crucial to devise strategies that optimize crop production in conditions of limited water availability. While potassium silicate has demonstrated effectiveness in mitigating drought stress in various crops, its specific impact on different cotton cultivars under drought conditions remains not fully clarified. This research aimed to assess the efficacy of six potassium silicate levels (0, 100, 200, 300, 400 and 500 mg L⁻¹) on four cotton genotypes (Zong main-113, Xin Nong-525, Xin lu Zhong-55, and Xin lu Zhong-66) under two field capacity levels (80% and 50% FC) in a sand culture. Foliar applied potassium silicate significantly improved photosynthetic efficiency, shoot biomass, root biomass, and leaf area under water stress (50% FC). The most substantial reduction in H₂O₂, malondialdehyde levels, and electrolyte leakage was recorded with potassium silicate applied at a rate of 400 mg L⁻¹. This concentration effectively mitigated reactive oxygen species accumulation, safeguarding plants against oxidative damage at 50% FC. Furthermore, potassium silicate contributed to maintaining water status, resulting in increased leaf water content and elevated water-soluble proteins in cotton plants. The order of drought resistance (50% FC) with the application of potassium silicate at 400 mg L⁻¹ was Zong Mian-113, Xin Nong-525, Xin lu Zhong-55, and Xin lu Zhong-66. The findings could help in selection of drought resistance cultivars of cotton in water limited conditions.

Currently, many techniques to alleviate the negative effects of water stress, specifically drought, on plants are frequently the subject of research. In this study, the effects of two different plant growth-promoting rhizobacterial (PGPR) species isolated from arid and semiarid areas whose activities under water stress were determined in a preliminary study on several physiological properties and nutrient uptake of watermelons grafted onto different rootstocks were investigated under deficit irrigation. In this study, the performance of two PGPRs (B₁: Paenarthrobacter aurescens and B₂: Pseudarthrobacter polychromogenes) inoculated into ungrafted watermelon (R₀ (Citrullus lanatus (Thumb.) Matsum and Nakai cv. Crimson Tide, CT)) and grafted watermelons (R₁: CT grafted onto citron watermelon rootstock (Citrullus lanatus var. Citroides) and R₂: CT grafted onto the hybrid rootstock TZ-148 (Cucurbita maxima Duchesne × Cucurbita moschata Duchesne)) were studied under different irrigation levels. Severe water stress negatively affected the physiological characteristics, such as stomatal conductance (gs) and photosynthesis efficiency (QPSII), of watermelon plants. Moreover, the contents of leaf mineral nutrients such as N, P, and K decreased significantly with increasing water stress. On the other hand, rootstocks improved the performance of sweet watermelon in terms of macronutrients such as N, K, and Mg and micronutrients such as Fe and Cu. Moreover, the drought-tolerant rootstocks (R₁ and R₂) used in this study protected watermelon plants against the negative effects of water stress by reducing gs compared to that of ungrafted plants. Moreover, although rhizobacteria did not have a significant effect on the gs, QPSII, or leaf water potential (LWP) of watermelon, they enhanced the uptake of minerals such as macro- and micronutrients from the soil by plants. Under full irrigation and particularly deficit irrigation, P. polychromogenes (B₂) increased the contents of macronutrients such as Mg and K, while P. aurescens (B₁) increased the contents of micronutrients such as Fe, Cu, Mn, and B in watermelons. Our results revealed that these two rhizobacterial species, which were isolated from arid and semiarid areas, contribute to the nutrient uptake of watermelon plants grown under water stress.

To investigate the quantitative and qualitative yields of different rapeseed genotypes under optimal water supply and restricted irrigation regimes, a split plot experiment was arranged in a randomized complete blocks design with three replicates in the 2018–19 and 2019–20 growing seasons. The Main plots included irrigation regimes at three levels of optimal water supply regime, withholding irrigation from the beginning of flowering, and withholding irrigation from the beginning of silique setting. The sub-plots contained 11 Iranian rapeseed genotypes (Dalgan, Zafar, Sarigol, RGS003, Hyola4815, Hyola401, Zabol10, Jerom, Jerry, Julius, and Jacomo). The highest rapeseed seed yield (3463 kg ha⁻¹), oil content (43.09%), and oil yield (1492 kg ha⁻¹) were obtained from the optimal water supply regime. Drought stress (restricted irrigation from silique setting and flowering stages) decreased seed yield (28 and 49%), oil content (4 and 7%), and oil yield (31 and 52%). Fatty acids compositions of rapeseed genotypes differently responded to drought stress conditions. Restricted irrigation regimes enhanced the linolenic acid, erucic acid, and glucosinolate contents, while the palmitic acid, oleic acid, and linoleic acid content were reduced when the rapeseed plants were subjected to drought stress. Overall, our findings suggest that the Sarigol genotype due to acceptable seed and oil yield as well as high-quality oil under three studied irrigation regimes can be recommended for cultivation in arid and semi-arid regions like Iran.

Plant treatments with biocontrol agents to deal with biotic stress are widely reported, but the information regarding detailed action mechanisms of biocontrol and host response is rarely reported. This study investigated a biocontrol bacterial agent, Bacillus cereus, to manage tomato bacterial wilt (BW) disease. The in vitro antibacterial potential of B. cereus was assessed, followed by the ability of B. cereus to colonize tomato roots and induce host resistance. Additionally, we tested the application of B. cereus for managing tomato BW disease. In vitro investigations revealed the volatile mediated antibacterial activity of B. cereus, indicating that B. cereus produces antibacterial volatiles against R. solanacearum. The effectiveness of B. cereus in colonizing tomato roots was evaluated through its transgenic GFP-tagged strains and confirmed through qPCR analysis. It was found that the biocontrol bacterium successfully colonized the host root. The B. cereus concentration reached 9.37 × 107 at 48 h. The tomato plants under bacterial wilt stress, when treated with B. cereus, showed upregulation of genes linked to the plant defense system. The application of B. cereus to soil infested with R. solanacearum and planted with tomato plants reduced the pathogen population in the soil, resulting in a reduction in disease severity and improved plant growth. This study suggests the biocontrol potential of B. cereus to manage bacterial wilt disease.

Fruit processing waste from Annona mucosa Jacq. (Annonaceae) is an interesting source of biomass for development of ecofriendly botanical insecticides. Here, we evaluated the lethal and sublethal effects of the ethanolic extract prepared from seeds of A. mucosa (ESAM; major component = acetogenin bis-tetrahydrofuran rolliniastatin-1) against Chrysodeixis includens (Walker) and Anticarsia gemmatalis Hübner, two major defoliators of soybean crops. In the initial trial, ESAM showed activity comparable or superior to our positive control (Azamax® 1.2 EC, at recommended rate). The larvae of C. includes survived at higher levels than A. gemmatalis when exposed to ESAM. To cause mortality of 50 and 90% of the population of A. gemmatalis, 66.91 and 288.36 mg kg⁻¹ was needed, respectively, whereas, for C. includens, 452.38 and 885.70 mg kg⁻¹ were required, respectively. In addition, 27.23 and 51.01 h were needed to cause 50% of mortality against A. gemmatalis and C. includens, respectively. Under semi-field conditions (greenhouse), the aqueous emulsion of ESAM (pre-commercial formulation) and Azamax® 1.2 EC caused larval mortality above 95% for both pest species exposed to treated soybean plants. These results show that A. mucosa processing waste can be a source of promising botanical insecticides for the management of C. includens and A. gemmatalis, which are the main economically lepidopteran defoliators of soybean crops.