Heat stress and the photosynthetic electron transport chain of the lichen Parmelina tiliacea (Hoffm.) Ach. in the dry and the wet state: differences and similarities with the heat stress response of higher plants

Thalli of the foliose lichen species Parmelina tiliacea were studied to determine responses of the photosynthetic apparatus to high temperatures in the dry and wet state. The speed with which dry thalli were activated by water following a 24h exposure at different temperatures decreased as the temperature was increased. But even following a 24h exposure to 50°C the fluorescence induction kinetics OJIP reflecting the reduction kinetics of the photosynthetic electron transport chain had completely recovered within 128min. Exposure of dry thalli to 50°C for 24h did not induce a K-peak in the fluorescence rise suggesting that the oxygen evolving complex had remained intact. This contrasted strongly with wet thalli were submergence for 40s in water of 45°C inactivated most of the photosystem II reaction centres. In wet thalli, following the destruction of the Mn-cluster, the donation rate to photosystem II by alternative donors (e.g. ascorbate) was lower than in higher plants. This is associated with the near absence of a secondary rise peak (~1s) normally observed in higher plants. Analysing the 820nm and prompt fluorescence transients suggested that the M-peak (occurs around 2-5s) in heat-treated wet lichen thalli is related to cyclic electron transport around photosystem I. Normally, heat stress in lichen thalli leads to desiccation and as consequence lichens may lack the heat-stress-tolerance-increasing mechanisms observed in higher plants. Wet lichen thalli may, therefore, represent an attractive reference system for the evaluation of processes related with heat stress in higher plant

Etude De L’impact De La Consanguinité Sur La Santé Des Descendants Dans La Population De Tiflet (Maroc)

Several studies confirm the implication of the consanguinity in health problems and some countries still preserve this marital behavior. In this study, our objective is the analysis of consanguinity’s impact on descendants’ health in the Tiflet city and its regions (Northwest of Morocco). Data was collected between June and November 2012 and it was conducted on 1000 families. The calculation of the rate of the mortality concerned 3345 alive born descendants, while the biological effects of the consanguinity study was made on 3241 descendants. The results of this study show a significant association between the consanguinity and its incidence on health, such as the morbidity, the mortality and the abortion in the descendants

Études Des Caractéristiques Et Des Déterminants Des Mariages Consanguins Dans La Ville De Tiflet (Maroc)

The practice of consanguineous marriage is still very widespread in Morocco and in the Arab-Muslim world, where the customs as well as the cultural, economic and social motivations have most often an influence on the marital choice within the family. The purpose of this study is to define the determinants of this practice in the city of Tiflet and regions (Morocco). A survey was conducted on 1000 pairs randomly sampled between June and November of 2012. The results reveal a high level of consanguinity (38.9 %) and a significant association between this marital practice and the geographical and sociocultural factors such as: the place of residence before marriage, the education level, the profession and the age in the marriage

Polyphosphate application influences morpho-physiological root traits involved in P acquisition and durum wheat growth performance

peer reviewedAbstract Background Among phosphate (P) fertilizers, polyphosphates (PolyPs) have shown promising results in terms of crop yield and plant P nutrition. However, compared to conventional P inputs, very little is known on the impact of PolyPs fertilizers on below- and above-ground plant functional traits involved in P acquisition. This study aims to evaluate agro-physiological responses of durum wheat variety ´Karim´ under different PolyPs applications. Three PolyPs fertilizers (PolyA, PolyB, and PolyC) versus one orthophosphate (OrthoP) were applied at three doses; 30 (D30), 60 (D60), and 90 (D90) kg P/ha under controlled conditions. The PolyPs (especially PolyB and PolyC) application at D60 significantly increased morphophysiological root traits (e.g., RL: 42 and 130%; RSA:40 and 60%), shoot inorganic P (Pi) content (159 and 88%), and root P acquisition efficiency (471 and 296%) under PolyB and PolyC, respectively compared to unfertilized plants. Above-ground physiological parameters, mainly nutrient acquisition, chlorophyll content and chlorophyll fluorescence parameters were also improved under PolyB and PolyA application at D60. A significant and positive correlation between shoot Pi content and rhizosphere soil acid phosphatase activity was observed, which reveal the key role of these enzymes in PolyPs (A and B) use efficiency. Furthermore, increased P uptake/RL ratio along with shoot Pi indicates more efficient P allocation to shoots with less investment in root biomass production under PolyPs (especially A and B). Conclusions Under our experimental conditions, these findings report positive impacts of PolyPs on wheat growth performance, particularly on photosynthesis and nutrient acquisition at D60, along with modulation of root morpho-physiological traits likely responsible of P acquisition efficiency

Les réponses morphologiques et anatomiques des racines de blé à des concentrations croissantes du phosphore sous des conditions de salinité

peer reviewedUnderstanding the role of nutrients in the alleviation of salt stress effects and the unrevealed significance of root system architecture for plant adaptation is one of the major research areas in the current context of agriculture. Root anatomy is also a valuable parameter to be considered in understanding how the root system counters soil salinity's effect on plant growth. Although Root Phosphorus Acquisition Efficiency (RPAE) under salt stress differs depending on plant species and the severity of salinity in the rhizosphere, optimising phosphorus (P) nutrition seems to bring positive results. This study was planned to investigate the combined effect of salinity and P-availability on root morphology and anatomy as well as nutrient uptake of wheat plants. A pot experiment was performed in open-field conditions using a Moroccan variety of durum wheat. Special emphasis was placed on how orthophosphate and polyphosphate fertilizer forms and phosphorus doses alter the morphology and anatomy of the roots under salt stress. Two soluble fertilizers were used: an orthophosphate (Ortho-A) and a polyphosphate (Poly-B) were applied at four P levels (0, 30, 45 and 60 ppm of P). Our findings showed that salt stress induced, at both anatomical and morphological levels, a series of modifications in the roots of wheat plants. Compared to salt-stressed and unfertilized plants, soluble P-fertilizers significantly increased soil available P, root P- content, RPAE, root length (RL), root surface area (RSA), root volume (RV), root mass density (RMD), root tissue water content (TWC), number of root tips, vascular cylinder diameter and SD/CT ratio. Furthermore, Poly-B showed a positive response in both morphological and anatomical parameters at lower doses while Ortho-A revealed significant results within the increase in P-concentration. The increased root parameters observed under P-treatments could determine the root performance and efficiency to acquire water and P and their transport to the aboveground organs of wheat plants under salinity

Optimization of macronutrients for improved grain yield of quinoa (Chenopodium quinoa Wild.) crop under semi-arid conditions of Morocco

In the context of climate change, quinoa represents a potential alternative crop for increasing crops diversity, agricultural productivity, and farmer’s income in semi-arid regions. However, appropriate crop management practices under limited water supply are still poorly documented. Quinoa, like other cultivated crops, needs optimum quantities of nutrients, especially nitrogen (N), phosphorus (P), and potassium (K), for better growth and high grain yield. To determine the adequate levels of nutrient requirements and their effect on quinoa growth and productivity, a field experiment was conducted during two growing seasons (2020–2021 and 2021–2022). The experiment was conducted in Ben Guerir region, north-central Morocco, and consisted of a randomized complete block design (RCBD) with three replications. The treatments studied consist of a combination of four N rates (0, 40, 80, and 120 kg ha−1), three P rates (0, 30, and 60 kg P2O5 ha−1), and three K rates (0, 60, and 120 kg K2O ha−1). The physiological, nutritional, and production parameters of quinoa were collected and analyzed. The results showed that the highest total biomass (3.9 t ha−1) and grain yield (0.8 t ha−1) under semi-arid conditions were obtained with 40 kg N ha−1, 60 kg P2O5 ha−1, and 120 kg K2O ha−1. The application of 40–60–120 kg ha−1 of N–P2O5–K2O increased plant height by 44%, chlorophyll content index by 96%, total biomass by 134%, grain yield by 112%, and seed weight by 118%. Among the three macronutrients, N was the most limiting factor, followed by K and P. Nutrients uptake data showed that quinoa needs 60 kg N, 26 kg P2O5, and 205 kg K2O to produce 1 t of grain yield. Our field results provide future recommendations for improving the agronomic and environmental sustainability of quinoa cultivation in dryland areas in Morocco

Worldwide development of agronomic management practices for quinoa cultivation: a systematic review

Quinoa (Chenopodium quinoa Wild.) is a drought and salinity-tolerant crop that originated in the Andes over 7000 years ago. It is adapted to different agroecological areas and can be grown from sea level to an altitude of 4000 m. The outstanding nutritional status of quinoa, with its high content of proteins, vitamins, and minerals, makes it a promising crop able to combat hunger and malnutrition in different countries in the 21st century. Quinoa cultivation has expanded from South America to Africa, Europe, Asia, and North America. Reviewing quinoa cropping practices will provide farmers with adequate recommendations for improving the agronomic and environmental sustainability of quinoa cultivation worldwide. For this reason, we conducted a systematic review of agronomic management practices in 148 field experiments conducted worldwide from 2000 to 2022. The collected data from the literature were analyzed and presented by location to determine high-performing genotypes, optimal planting dates, and other adequate cropping practices affecting quinoa performance and yield. Results showed that quinoa could be successfully cultivated in the new farming areas. Quinoa yields were higher than those reported in its place of origin, ranging from 108 kg ha-1, obtained by KU-2 in Washington State, to 9667 kg ha-1, obtained by Longli in China. Although quinoa is considered a crop with low input requirements, positive grain yield response was observed following increasing fertilization rates. Quinoa needs 2 to 4.6 kg of nitrogen to produce 1q of grain yield. In terms of phosphorus and potassium, quinoa needs 3.7 kg P2O5 and 4.3 kg K2O to produce 1 ton of total biomass. Quinoa has low water requirements (300-400 mm). However, a positive response was recorded with water quantities up to 866 mm. During our investigation, weed control in quinoa crop is still undeveloped and usually done manually. Research addressing this issue can increase quinoa yields and decrease the production cost. Downey mildew and birds’ attack are the major phytosanitary problems affecting quinoa grain yield. Other pests such as miners and aphids can also affect the health of quinoa, but their injury is not a serious problem. After the harvest, saponins found in the out layer of the seed can be removed through washing and mechanical pearling process, but the latter technic was found to be efficient and cost effective to reduce the saponin content. Our results constitute the first recommendation base for the adequate worldwide agronomic practices of quinoa crop

Food Legumes and Rising Temperatures: Effects, Adaptive Functional Mechanisms Specific to Reproductive Growth Stage and Strategies to Improve Heat Tolerance

Ambient temperatures are predicted to rise in the future owing to several reasons associated with global climate changes. These temperature increases can result in heat stress- a severe threat to crop production in most countries. Legumes are well-known for their impact on agricultural sustainability as well as their nutritional and health benefits. Heat stress imposes challenges for legume crops and has deleterious effects on the morphology, physiology, and reproductive growth of plants. High-temperature stress at the time of the reproductive stage is becoming a severe limitation for production of grain legumes as their cultivation expands to warmer environments and temperature variability increases due to climate change. The reproductive period is vital in the life cycle of all plants and is susceptible to high-temperature stress as various metabolic processes are adversely impacted during this phase, which reduces crop yield. Food legumes exposed to high-temperature stress during reproduction show flower abortion, pollen and ovule infertility, impaired fertilization, and reduced seed filling, leading to smaller seeds and poor yields. Through various breeding techniques, heat tolerance in major legumes can be enhanced to improve performance in the field. Omics approaches unravel different mechanisms underlying thermotolerance, which is imperative to understand the processes of molecular responses toward high-temperature stress

Vitalité des plantes d'orge ("Hordeum vulgare" L.) en conditions de stress hydrique et thermique analysée par la fluorescence chlorophyllienne

L'évaluation de la tolérance aux stress hydrique et thermique et leur combinaison a été étudiée chez des variétés d'orge d'origine marocaine. La technique de fluorescence chlorophyllienne a été intensivement employée "in vivo" comme outil non destructeur pour évaluer les réponses des différentes variétés ainsi que d'autres paramètres (RWC, Indexe de plastochrone, âge des feuilles...). Les courbes OJIP de la fluorescence chorophyllienne ont été analysées par JIP-test qui traduit les changements provoqués par le stress en question en paramètres quantitatifs. Les réponses des plantes d'orge au stress thermique ont été évaluées au niveau du photosystème II. Un antagonisme apparent entre le stress thermique et hydrique a été observé. La caractéristion des plantes par la fluorescence chlorophyllienne est basée sur l'extraction d'un certain nombre de détails et de paramètre de chaque courbe OJIP. Il est essentiel d'évaluer le potentiel de la fluorescence chlorophyllienne pour détecter les réponses des différentes variétés