Composición nutricional de seis gramíneas tropicales del estado de Jalisco, México

El objetivo de este estudio fue evaluar la composición química de seis gramíneas forrajeras para el trópico húmedo y seco mexicano: Andropogon gayanus, Andropogon gerardii, Cenchrus ciliaris, Chloris gayana, Megathyrsus maximus y Urochloa brizantha. Las muestras se colectaron en noviembre de 2019, en Tonaya, Jalisco, México. Se determinaron: materia seca, cenizas, proteína cruda (total e insoluble), extracto etéreo, fibra detergente neutro, fibra detergente ácido, hemicelulosa, lignina y celulosa. La evaluación se realizó en el Laboratorio de Nutrición Animal del Departamento de Zootecnia, Universidad Autónoma Chapingo, Texcoco, Estado de México. Cada gramínea se evaluó por triplicado y cada repetición se consideró como unidad experimental. Las medias de composición química fueron separadas mediante la prueba de Tukey (p < 0.05). La correlación entre cada par de variables (p < 0.05) se estimó mediante el coeficiente de Pearson (p < 0.05). A mayor porcentaje de proteína total (p < 0.05) menor porcentaje de extracto etéreo y mayores porcentajes de cenizas y de proteína insoluble. Además, a mayor porcentaje de proteína insoluble, menor porcentaje de lignina (p < 0.05). Probablemente, la proteína se concentra en su fracción insoluble a expensas del extracto etéreo y la lignina. Consecuentemente, gran-tallo-azul (Andropogon gerardii) mostró porcentajes altos de proteína total (10.27%) y cenizas (7.88%), y bajos de lignina (5.23%) y extracto etéreo (1.37%); pero su proteína insoluble no fue tan elevada (2.06%) como la de guinea (Megathyrsus maximus) (6.08%). Por tanto, A. gerardii tuvo el mejor contenido nutricional a los 35 días de rebrote.

Reação de acessos de Cenchrus a Pyricularia grisea no semiárido brasileiro

O fungo Pyricularia grisea causa manchas foliares em capim buffel (Cenchrus ciliaris), sendo um problema em pastagens dessa forragem no Texas, EUA e México. Apesar desta doença não apresentar problemas graves ao capim buffel no Semiárido brasileiro, a busca de germoplasma com algum nível de tolerância a esta doença tem importância preventiva. O objetivo neste estudo foi avaliar a reação de acessos de Cenchrus spp. a P. grisea, em infecção natural. Foram avaliados 20 acessos pertencentes ao Banco Ativo de Germoplasma (BAG) de Cenchrus da Embrapa Semiárido, em blocos casualizados com três repetições e parcela contento 20 plantas. As avaliações foram realizadas em dois ciclos de avaliação em 2019 e 2020, no período chuvoso, quando as condições ambientais para o desenvolvimento da doença eram favoráveis. Para a avaliação da severidade da doença foi utilizada uma escala de notas variando de 1 a 4 e percentual da área foliar lesionada. Os dados médios das notas por parcelas foram submetidos a análise de variância e as médias comparadas pelo teste de Scott e Knott, à 5% de significância. Houve efeito significativo para a tolerância à doença. Dez acessos receberam nota média acima de 3 (CPATSA 83476; CPATSA 79151; CPATSA 79150; CPATSA 79591; CPATSA 90194; CPATSA 79144; CPATSA 79558; CPATSA 79134; CPATSA 90570; CPATSA 79613), nas duas avaliações, indicando uma moderada resistência em relação a testemunha suscetível, a cultivar Biloela. Existe variabilidade a ser explorada para reação a P. grisea no BAG de Cenchrus da Embrapa Semiárido.

Combining Rainwater Harvesting and Grass Reseeding to Revegetate Denuded African Semi-arid Landscapes

In African drylands, perennial grasses preferred by grazing livestock are disappearing at an alarming rate. This has led to recurrent livestock feed shortages threatening pastoralist’s livelihoods. Combining native grass reseeding and rainwater harvesting offers a viable and innovative solution to reverse this trend. However, studies to determine how biomass yields are affected by soil moisture availability attributed to in situ rainwater harvesting in African drylands are limited. We investigated how biomass yields of three grasses native to Africa, i.e., Enteropogon macrostachyus (Bush rye grass), Cenchrus ciliaris (African foxtail grass), and Eragrostis superba (Maasai love grass), are affected by soil moisture content in a typical semi-arid landscape. Rainwater harvesting structures included trenches, micro-catchments and furrows. Additionally, rain runoff was diverted from an adjacent road used as a catchment area. Soil moisture was measured between November 2018 and August 2019 using PlantCare Mini-Logger sensors installed at 40 and 50 cm depths and 0, 1, 5 and 15 m away from the trench. Quadrat method was used to determine biomass yields in August 2019. Peaks in soil moisture were observed after rainfall events. Soil moisture content gradually decreased after the rainy season, but was higher closer to the trench. This is attributed to the prolonged rainwater retention in the trenches. Biomass yields were in the order Eragrostis superba > Cenchrus ciliaris > Enteropogon macrostachyus. Biomass production was higher near the trenches for all the studied species. Sensitivity to soil moisture demonstrated by the magnitude to yield reduction during the growing season was in the order Eragrostis superba > Cenchrus ciliaris > Enteropogon macrostachyus. These results suggest that Eragrostis superba is more sensitive to drought stress than Enteropogon macrostachyus that is adapted to a wide range of soil moisture conditions. We demonstrated that in situ rainwater harvesting structures enhanced soil moisture availability and displayed great potential for revegetating denuded natural rangelands in semi-arid African landscapes. Thus, combining rainwater harvesting and reseeding techniques can produce measurable improvements in pastoral livelihoods and should be incorporated in dryland development policies in the region. Ultimately, incorporating such innovative strategies can strengthen the effectiveness of ecological restoration in African drylands to meet the objectives of the UN Decade on Ecosystem Restoration and achieving the UN Sustainable Development Goals. Graphical abstract

Biochemical responses of Digitaria commutata and Cenchrus ciliaris to water stress: antioxidative reactions, proline and soluble sugars accumulation

The impact of water stress on antioxidant enzyme activities, proline, soluble sugars, and carotenoids contents found in Digitaria commutata and Cenchrus ciliaris plants was investigated. Two different watering regimes were used on plants over a period of three months. Water stress decreased total chlorophyll content in plants, but increased carotenoids content. Interestingly, no change was observed in the quantum yield of PSII photochemistry (Fv/Fm). Malondialdehyde (MDA) content increased to a higher extent in both species. Enhanced activities of all the enzymes (peroxidase, catalase, and superoxide dismutase) studied, except for catalase in the roots were observed. Proline and soluble sugars contents increased significantly following water stress exposure. No clear differences were found between both species. The results link drought tolerance of Digitaria commutata and Cenchrus ciliaris plants with better capabilities of anti-oxidative system. Additionally, it is linked to the accretion of osmoprotectants proline and soluble sugars when exposed to drought.

Análisis de la respuesta productiva ante la variabilidad climática en tipos de vegetación exótica y nativa del Desierto Sonorense

La introducción de zacate buffel (Cenchrus ciliaris) para incrementar la producción de forraje ha provocado modificaciones en grandes extensiones de terreno del Desierto Sonorense. Aunado a lo anterior, nuestro conocimiento acerca de la influencia de fenómenos climáticos, como El Niño, sobre la dinámica de productividad en la vegetación, es limitado. El presente trabajo pretende analizar la actividad fotosintética/productiva de la vegetación del Desierto Sonorense en sitios con matorral subtropical y praderas de buffel para determinar diferencias entre fases del fenómeno El Niño Oscilación del Sur (ENSO acrónimo en inglés). Se establecieron sitios de estudio en comunidades vegetales con y sin buffel. Se adquirieron imágenes satelitales del “Moderate Resolution Imaging Spectroradiometer (MODIS)” para derivar el Índice de Vegetación de Diferencia Normalizada (NDVI, acrónimo en inglés) en compuestos de 16 días. Se obtuvo información acerca de las diferentes fases de El Niño desde 2001 hasta 2017. Los resultados sugieren actividad productiva mayor durante la fase Neutra que durante las fases El Niño o La Niña. También, el matorral subtropical presenta mayor actividad productiva que las praderas de buffel en cualquiera de las combinaciones estación-fase analizadas, excepto en La Niña durante el verano

Ecotypic Morphological and Physio-Biochemical Responses of Two Differentially Adapted Forage Grasses, Cenchrus ciliaris L. and Cyperus arenarius Retz. to Drought Stress

Crop performance and yield are the results of genotypic expression as modulated by continuous interaction with the environment. Among the environmental aspects, drought and salinity are the most important factors, which limit the forages, including grasses, on a global basis. Grass species have the ability to grow under low water conditions and can produce high dry yield, proteins, and energy in areas exposed to drought stress. For this purpose, we conducted the present study to understand the response of forage grasses under drought stress from two different regions (Salt Range and Faisalabad) of Punjab, Pakistan. Two ecotypes of each grass species (Cenchrus ciliaris L. and Cyperus arenarius Retz.) were grown in pots at the botanical research area, Government College University Faisalabad, Pakistan. A group of plants were subjected to drought stress (60% field capacity) and controlled (100% field capacity) after three weeks of seed germination. The results from the present study depicted that the fresh and dry weights of root and shoot were decreased significantly under drought conditions. Moreover, C. ciliaris of the Salt Range area showed more resistance and higher growth production under drought stress. The chlorophyll (a and b) contents were also decreased significantly, while MDA, total soluble sugars, and proline levels were increased significantly under water-limited environments in the C. arenarius of Salt Range area. Enzymatic antioxidants (superoxidase dismutase (SOD) and peroxidase (POD)) and leaf Na+ were significantly raised in C. arenarius under drought stress collected from the Faisalabad region. Cenchrus ciliaris showed higher level of H2O2, total soluble proteins, glycinebetaine, catalase (CAT) and POD compared to C. arenarius. It also retained more leaf and root Ca2+, and root K+ under drought stress. It was concluded from the study that C. ciliaris is more resistant to drought in biomass production collected from the Salt Range area. The results suggested that C. ciliaris can be more widely used as a forage grass under water-scarce conditions as compared to C. arenarius.

Allelopathy effect of Prosopis juliflora on selected grass species (Cenchrus ciliaris, Paspalidium desertorum and Lintonia nutans)

Prosopis juliflora growing frightening rate of invasiveness had affected the livelihood of the pastoral communities in the Amibara rangeland of Afar National Regional State. Therefore, the aim of this study was to investigate the allelopathy effect of an aqueous leaf, bark, and root extracts of Prosopis juliflora on selected grass species such as Cenchrus ciliaris, Paspalidium desertorum, and Lintonia nutans. A total of 10 soil samples were collected from the Amibara rangeland of Afar National Regional State. The collected soil samples were mixed in a plastic bag to get composite soil. Further, the composite soil sample was subjected to analysis of physic-chemical characters (pH, soil organic matter, phosphorus, and nitrogen content). To study the allelopathy effect of Prosopis juliflora on selected grass species. To this, aqueous extracts were prepared from powdered leaf, bark, and root of Prosopis juliflora at different concentration levels (0%, 1%, 2.5%, 5%, and 10%). Further, the extracts were subjected to analysis of seed germination percentage and seedling growth of selected grass species such as Cenchrus ciliaris, Paspalidium desertorum and Lintonia nutans. Prosopis juliflora showed a significant inhibitory effect on seed germination of Cenchrus ciliaris, Paspalidium desertorum, and Lintonia nutans. grass species. Among the leaf, bark, and root aqueous extracts, the leaf showed the highest inhibitory effect on seed germination percentage, and the effect also concentration-dependent. Prosopis juliflora aqueous extracts of leaf, bark, and root of were exhibited significant inhibition on the fresh shoot biomass weights of Cenchrus ciliaris, Paspalidium desertorum and Lintonia nutans. when compared to the control. While the fresh shoot biomass weight of Cenchrus ciliaris and Paspalidium desertorum was highly deteriorated at (5% and 10%). Whereas, the fresh shoot biomass weight of Lintonia nutans momentously retarded at (1% and 5%) as compared to the control.

Ruminal and Intestinal Morphometric Parameters of Lambs Fed Diets Containing Mimosa Tenuiflora (Willd.) Hay Replacing Buffel Grass Hay

The objective in this study was to evaluate morphometric parameters of the ruminal papillae and intestinal villi of lambs fed diets containing Mimosa tenuiflora (Willd.) hay replacing Buffel grass (Cenchrus ciliaris L.) hay. Twenty-eight Santa Inês lambs with initial body weight of 20.3 ± 1.49 kg were used, being distributed in a completely randomized design with four treatments (0, 333, 670 and 1000 g/kg DM). The width of the ruminal papillae was not affected (P > 0.05), while their area linearly decreased (P = 0.01) as the level of M. tenuiflora hay increased. In the duodenum, the height (P < 0.0001) and the surface (P = 0.01) of the villi linearly decreased with the increase in the level of M. tenuiflora, while the width (P = 0.0001) and the area (P = 0.03) quadratically decreased with minimum values of 132.95 and 50,625.53 µm at the levels of 436 and 575 g/kg, respectively. There was a quadratic increase in the height of the jejunum villi (P < 0.0001) with a maximum value of 623.22 µm at the level of 333 g/kg, while the width quadratically decreased with a minimum value of 143.33 µm at the level of 526 g/kg and the area linearly decreased (P = 0.02). The height of the ileum villi (P = 0.0003) as well as the depth of the crypts in all segments (P < 0.001) linearly decreased. Therefore, it is suggested the substitution of C. ciliaris hay by M. tenuiflora hay up to 333 g/kg DM.

Single-cell transcriptome profiling of buffelgrass (Cenchrus ciliaris) eggs unveils apomictic parthenogenesis signatures

Apomixis, a type of asexual reproduction in angiosperms, results in progenies that are genetically identical to the mother plant. It is a highly desirable trait in agriculture due to its potential to preserve heterosis of F1 hybrids through subsequent generations. However, no major crops are apomictic. Deciphering mechanisms underlying apomixis becomes one of the alternatives to engineer self-reproducing capability into major crops. Parthenogenesis, a major component of apomixis, commonly described as the ability to initiate embryo formation from the egg cell without fertilization, also can be valuable in plant breeding for doubled haploid production. A deeper understanding of transcriptional differences between parthenogenetic and sexual or non-parthenogenetic eggs can assist with pathway engineering. By conducting laser capture microdissection-based RNA-seq on sexual and parthenogenetic egg cells on the day of anthesis, a de novo transcriptome for the Cenchrus ciliaris egg cells was created, transcriptional profiles that distinguish the parthenogenetic egg from its sexual counterpart were identified, and functional roles for a few transcription factors in promoting natural parthenogenesis were suggested. These transcriptome data expand upon previous gene expression studies and will be a resource for future research on the transcriptome of egg cells in parthenogenetic and sexual genotypes.