Biostimulant effects of lanthanum (La) on crop growth, yield, and quality

Objective: To analyze the various effects that the use of La as an inorganic biostimulant has on growth, yield and quality of different crop plants. Design/methodology/approach: A search in recent literature related to the effects of lanthanum on various economically important crops was conducted. Subsequently, the most relevant information was selected, analyzed and grouped by type of effect. Results: The addition of lanthanum at low doses has been tested in different crop plants. It has been proven that La increases growth, development and quality in various species. Likewise, positive effects have been reported in germination, in the absorption of nutrients, in mitigating the deficiencies of some essential elements, as well as in the promotion of physiological and biochemical responses. Limitations/implications of the study: The analyzed results have been generated in a great diversity of plant species, under different production systems, with dissimilar doses, as well as with different sources and application methods. This situation represents a challenge, since it hinders the possibility to issue general recommendations. Findings/conclusions: Lanthanum improves yield and quality, as well as some physiological, biochemical and nutritional responses in different crops of economic importance

Silicon increases seed weight and initial seedling growth of maize under non-stress conditions, and improves the index of velocity of germination under salt stress conditions

Salinity is one of the most critical factors affecting agriculture worldwide. The application of beneficial elements like silicon (Si) is one of the alternatives to mitigate its effects. In this research, we evaluated the effect of Si applied during seed imbibition on mitigating the negative effects caused by salinity during the germination and initial growth phases of maize (Zea mays L.) SB-308 seedlings. Seed pre-treatment during the imbibition was made with 0.0-, 1.5- and 3.0-mM Si. Afterwards, seeds that were imbibed were placed in plastic containers and treated with 0, 80, 160, and 240 mM NaCl. The evaluated concentrations of Si and NaCl gave rise to 12 treatments. Pre-treated seeds with 3 mM Si had an increase of weight after imbibition, 5.1% higher than the control. The treatments obtained from combining NaCl and Si levels did not affect the total and relative germination. The radicle length increased by 13.6% with 3 mM Si compared to the control. Conversely, it was lower with increasing salinity. These trends were observed in plant height. The interaction of the study factors produced an increase in the radicle length in the interval from 0 to 160 mM NaCl, when the Si dose was increased. However, there were no significant differences among equal levels of salinity without Si. It is concluded that Si increased the absorption of water during the imbibition and raised the index of velocity of germination under salinity, except in the dose 240 mM NaCl. Likewise, the pre-treatment of seeds with Si tends to increase radicle length under saline conditions

El ácido salicílico aumenta la acumulación de macroy micronutrientes en chile habanero

Abstract The results of the effect of salicylic acid (AS) on the nutritional absorption of Capsicum chinense are presented. 1 μM of AS was sprayed on the canopy of habanero pepper seedlings and distilled water as control. The results obtained show that aspersions of 1μM of salicylic acid (SA) significantly increase the length, weight, weight and dry weight of roots, stems, leaves and fruits of this species, as well as the levels of nitrogen (N), phosphorus (P) ) and potassium (K) in the different organs of the plants at the time of harvest. The accumulation of N, P and K was higher in fruits (116, 110 and 97%), leaves (45.5, 39.4 and 29.1%), root (52.6, 17.0 and 29.4%) and in stem (5, 39.4 and 28.3%) on the values of the control plant. The levels of copper, zinc, manganese, iron, boron, calcium and magnesium were also increased in most tissues by the effect of AS. It is proposed that the positive effect of the AS of increasing the size of the roots favors the absorption and accumulation of macro and micronutrients in the tissues of the plant.Resumen Se presentan los resultados del efecto del ácido salicílico (AS) en la absorción nutrimental de Capsicum chinense. Se asperjó 1 µM de AS, al dosel de plántulas de chile habanero y agua destilada como control. Los resultados obtenidos demuestran que aspersiones de 1µM de ácido salicílico(AS) incrementa significativamente la longitud, peso freso y peso seco de raíces, tallos, hojas y frutos de esta especie, al igual que los niveles de nitrógeno (N), fósforo (P) y potasio (K) en los diferentes órganos de las plantas al momento de la cosecha. La acumulación de N, P y K fue superior en frutos (116, 110 y 97%), hojas (45.5, 39.4 y 29.1%) raíz (52.6, 17 y 29.4%) y en tallo (5, 39.4 y 28.3%) sobre los valores de la planta control. Los niveles de cobre, zinc, manganeso, hierro, boro, calcio y magnesio también fueron incrementados en la mayoría de los tejidos por el efecto del AS. Se propone que el efecto positivo del AS de incrementar el tamaño de las raíces favorece la absorción y acumulación de macro y micronutrientes en los tejidos de la planta

Nitrogen supply and shading affect morphology and composition of the essential oil in marigold (Tagetes erecta L.)

Terrestrial plants are constantly exposed to multiple environmental signals that influence their metabolism. Among these signals, nitrogen (N) nutrition and light affect importantly diverse metabolic and physiological processes. Herewith the effects of N nutrition (8.47, 12.71 and 16.94 mg · L−1 N) and shading percentages (0 and 70%) on plant morphology and chemical composition of the essential oil of marigold (Tagetes erecta L.) ‘Inca’ were assessed. Increasing N levels enhanced the number of secondary branches and the flower diameter, while shading reduced height of side branches, number of primary branches and opened flower buds. In leaves, flowers and stems, 15 different compounds were identified. In leaves, low and medium N levels and high light level increased the synthesis of ocimene, limonene and piperitone. As well, medium and high N doses, independently of the light level, stimulated the synthesis of caryophyllene and β-phellandrene in leaves. Nevertheless, increasing N doses and shading level decreased the synthesis of β-myrcene and α-pinene in leaves. In flowers, medium N level and high light intensity increased the synthesis of trans-pinene. Piperitone and verbenone were identified only in flowers of plants with high N doses and lower light intensity. In the stems, caryophyllene, piperitone and β-farnesene were more abundant with medium and high N levels. The interaction of study factors differentially affected both morphological variables and the composition of essential oil among organs studied. Therefore, N nutrition and light intensity are key factors that modify the morphology and composition of the essential oil in T. erecta

Towards resolving the double classification in Erythraeus (Actinotrichida: Erythraeidae): matching larvae with adults using 28S sequence data and experimental rearing

The taxonomy of free-living adults and heteromorphic parasitic larvae of Parasitengona mites has in the past been treated independently resulting in a double classification. Correct linkage of names still remains unknown for many species. A holistic understanding of species is imperative for understanding their role in ecosystems. This is particularly true for groups like parasitengone mites with a radically altered lifestyle during development—parasitic to predatory. Here, we infer linkages of three nominal species of Erythraeus, using matching with 28S DNA sequence data from field-collected specimens and through laboratory rearing. The general mixed Yule coalescent method (GMYC) was used to explicitly test if field-collected specimens representing heteromorphic life instars were conspecific. The field-collected larvae were allocated to adults of Erythraeus cinereus and Erythraeus regalis, respectively. Laboratory rearing of the same two species confirmed the matching done by DNA. Rearing was also successful for Erythraeus phalangoides after eggs were treated to an imitated winter diapause. This integrative taxonomic approach of molecular, morphological, and rearing data resulted in the following synonyms: E. phalangoides (De Geer, 1778) [= Erythraeus adrastus(Southcott, 1961), syn. nov.], E. cinereus (Dugès, 1834) [= Erythraeus jowitae Haitlinger, 1987, syn. nov.], and E. regalis (C.L. Koch, 1837) [= Erythraeus kuyperi (Oudemans, 1910), syn. nov., = Erythraeus gertrudae Haitlinger, 1987, syn. nov.]. The molecular evidence confirmed the separate identity of three further members of the genus. We provide redescriptions of E. phalangoides, E. cinereus, and E. regalis after modern standards, and neotypes are designated

Genomic surveillance reveals dynamic shifts in the connectivity of COVID-19 epidemics

Summary: The maturation of genomic surveillance in the past decade has enabled tracking of the emergence and spread of epidemics at an unprecedented level. During the COVID-19 pandemic, for example, genomic data revealed that local epidemics varied considerably in the frequency of SARS-CoV-2 lineage importation and persistence, likely due to a combination of COVID-19 restrictions and changing connectivity. Here, we show that local COVID-19 epidemics are driven by regional transmission, including across international boundaries, but can become increasingly connected to distant locations following the relaxation of public health interventions. By integrating genomic, mobility, and epidemiological data, we find abundant transmission occurring between both adjacent and distant locations, supported by dynamic mobility patterns. We find that changing connectivity significantly influences local COVID-19 incidence. Our findings demonstrate a complex meaning of ‘local’ when investigating connected epidemics and emphasize the importance of collaborative interventions for pandemic prevention and mitigation