Effect of Seed Hydropriming on Seedling Emergence and Growth of Chickpea (Cicer arietinum L.) under Adverse Climatic Condition of Drought and Salinity

Aim: Assessment of influence of seed hydropriming in seed and seedling vigour enhancement for stress tolerance in chickpea which is important for successful crop production under erratic climate change causing drought and salinity stress severely affecting the seedling emergence and establishment especially in arid and semi arid regions of the world. Study Design: A three factorial randomised block design was used in the study, involving seed hydropriming treatment, chickpea varieties and growth conditions. Place and Duration of the Study: The experiment was conducted in Department of Seed Science and Technology, University of Agricultural Sciences, Dharwad, India, during the year 2018. Methodology: Six months old chickpea seeds of variety JG-11 and Annigeri-1 were hydroprimed for 12 hours at 25°C in dark condition. The primed and unprimed control seeds are sown under normal, drought and salinity conditions imposed in pots under controlled conditions. The data recorded were analysed for Analysis of Variance (ANNOVA). Results: The result of the experiment revealed that, upon seed hydropriming an average of 19 per cent increase in seedling emergence and 53.3 per cent increase in seedling vigour index was observed as compared to unprimed control seeds irrespective of variety and the abiotic stress conditions.

Characterization of cultural beneficial bacterial diversity for plant growth promoting attributes associated with rice rhizosphere

Aim: The study was undertaken to isolate, characterize and molecularly identify plant growth promoting rhizobacteria (PGPR) associated with rice rhizosphere occurring in Gangetic plains of the country. Methodology: One hundred forty three plant growth promoting rhizobacteria were isolated on various culture media and characterized culturally and morphologically through Scanning Electron Microscope. These rhizobacterial isolates were further screened for plant growth promoting activities like HCN production, siderophore production and phosphate solubilisation. The 16S rDNA sequencing was done to decipher phylogenetic relationship among 19 selected PGPRs. Besides, these were also tested for anti-oxidative enzyme production to mitigate deleterious effects of various stresses on plant growth and metabolism. Results: Nineteen potential plant growth promoting rhizobacteria were characterized for plant growth promoting attributes and were indentified at molecular level. Rice is well colonized by bacteria mainly Bacillus spp., Pseudomonas spp., Burkholderia sp., and Acinetobactor spp., Rice seeds treated with microbial consortium of MAU 143 + MRT 84 recorded in increased antioxidant production–SOD activity (0.02 U mg−1 f.w.t.), POX activity (0.16 U mg−1 f.w.t.), POP activity (0.06 U mg−1 f.w.t.) and TPC assay (1.17 µg gallic acid mg-1 extract) which might have stimulated the growth of radical (2.2 cm) and plumule (1.6 cm) over control. These three PGPRs viz., MAU 143, MRT 84 and MRT 92 strain showed great potential to improve antioxidant and total polyphenol production and seed vigour of rice seedlings. The identified rhizobacterial strains may be used for plant growth promotion and improvement in nutrients mobilization and oxidative stresses in rice production. Interpretation: The study suggested that plant growth promoting rhizobacteria isolated from rice rhizosphere have greater potential to improve soil nutrients status while provide resistance against infection of pathogenic microbes due to production of anti-oxidative enzymes and phenolic compounds in rice seedlings.

Spermine induced protection of onion seed vigour and viability during accelerated ageing

Aim: The aim of the present study was to investigate the role of spermine, a polyamine as a protective agent on accelerated ageing of onion seeds. Methodology: Onion seeds variety Pusa Riddhi was primed with six concentrations of spermine (0.10 mM to 1.25 mM) and also with hydration and halopriming (2% K2HPO4). Hydrated, haloprimed and un-primed seeds were used as control. The primed and control seeds were accelerated aged at 45 oC and 100 % RH for 72 hr. Seed quality was assessed in control, freshly primed seeds, and in primed seeds subjected to accelerate ageing. Results: All priming treatments enhanced the seed quality, there was 2.34–20.33 % increase in germination. Seed priming with 2% K2HPO4 had highest seed quality improvement which was at par with 1.25 mM spermine primed seeds. Enhanced seed vigour and the activity of antioxidant enzymes over un-primed seeds was observed in both 2% K2HPO4 and spermine primed seeds over unprimed seds. Seeds primed with 1.25 mM spermine recorded 66.66 % and 650 % increase in the activity of ROS scavenging enzymes SOD and POD respectively, but they were at par with halopriming. After accelerated ageing, deterioration in seed quality was minimal in seeds primed with spermine. Seeds primed with 1.25 mM spermine recorded 21.33% higher germination, 62.10 % higher speed of germination, 26.56 % longer seedlings, 13.68 % heavier seedlings and 175 % and 200 % higher SOD and POD activity as comparised to un-primed seeds. Seeds primed with 1.25 mM spermine also performed better over halopriming and hydropriming treatments. Interpretation: Onion seed priming with 1.25 mM spermine was most effective treatment in enhancing the seed germination and vigour under accelerated ageing conditions.

Viabilidad y germinación de semillas de Hechtiaperotensis (Bromeliaceae) / Viability and germination of Hechtia perotensis (Bromeliaceae) seed

ResumenPoblaciones endémicas de Hechtiaperotensis se han descrito en Puebla y Veracruz, México. La recolección de semillas de buena calidad permite su uso en conservación, investigación y restauración ecológica. Algunos compuestos para evaluar la calidad de las semillas silvestres y endémicas, como nitrato de potasio (KNO3) y ácido giberílico (AG3), se utilizan para incrementar la germinación de las semillas y disminuir la latencia. La prueba de cloruro de trifeniltetrazolio (tetrazolio) se correlaciona con la viabilidad de las semillas porque se basa en la actividad de las deshidrogenasas de tejidos vivos que catalizan la respiración mitocondrial. El objetivo de este estudio fue conocer el tamaño y el peso de las cápsulas y las semillas y la germinación y viabilidad de las semillas de H. perotensis recolectadas en Veracruz en 2012 y 2015. Las hipótesis fueron (1) que la germinación y la viabilidad de las semillas son independientes del año de recolecta, (2) que hay una concentración adecuada de tetrazolio para identificar la viabilidad de las semillas y (3) que el pretratamiento con KNO3 o AG3 incrementa la germinación de las semillas. La germinación se evaluó con un diseño completamente al azar con tres tratamientos (testigo y promotores de la germinación KNO3 0.2 % y AG3 500 mg/L), cuatro tratamientos para la prueba de viabilidad (testigo, 0.2, 0.5 y 1.0 % de tetrazolio) y seis repeticiones de cada tratamiento. La germinación se evaluó en 100 semillas y la viabilidad en 25. Los resultados entre y dentro de años se analizaron con ANDEVA y prueba de comparación múltiple de medias de Tukey. La proporción de semillas no germinadas se cuantificó junto con el número de plántulas normales y anormales, semillas con embrión viable o sin él, y con viabilidad baja o sin viabilidad. En promedio la muestra recolectada en 2012 tuvo 36 % de semillas con embrión viable, 7 con viabilidad baja, 24 % no viables y 33 % sin embrión. Este resultado fue significativamente diferente al de 2015, que presentó 87 % de embriones viables, 10 % con viabilidad baja, 0 % no viables y 3 % sin embrión. La germinación también fue significativamente diferente entre los años (22 y 92 %). Los tratamientos pregerminativos no modificaron la germinación. La germinación y la viabilidad de las semillas de H. perotensis varían significativamente entre los años de recolecta.

Abstract:Endemic populations of Hechtiaperotensis have been described in Puebla and Veracruz, Mexico. Good quality seed collections can be used in conservation, research and ecological restoration. To evaluate seed quality of wild and endemic species, some compounds are used as effective promoters of germination, such as potassium nitrate (KNO3) and gibberellic acid (AG3), because they increase seed germination capacity and reduce latency. The triphenyl tetrazolium chloride (tetrazolium) test correlates seed viability because it is based on the activity of dehydrogenases in live tissues that catalyze mitochondrial respiration. The objective of this study was to obtain information on size and weight of capsules and seeds and seed germination and viability of H.perotensis, collected in Veracruz in the year 2012 and 2015. The hypotheses were 1) that seed germination and viability are independent of the year of collection, 2) that there is a tetrazolium concentration that can identify seed viability better than others, and 3) that pretreatment with KNO3 or AG3 improves seed germination. Seed germination was assessed using a completely randomized design with three treatments (control and the germination promoters 0.2 % KNO3 and 500 mg/L AG3), four treatments for the viability test (control, 0.2, 0.5 and 1.0 % of tetrazolium) and six replicates for each treatment. A total of one hundred seeds for germination experiments, and 25 seeds for the viability test were used. The results between and within years were analyzed with ANOVA and multiple comparison with the Tukey test. The proportion of non-germinated seeds was quantified along with the number of normal and abnormal seedlings, seeds with viable embryo, seeds without embryo, and seeds with low or no viability. On average, for the 2012 collected sample, 36 % had viable embryos, 7 % had low viability, 24 % were not viable and 33 % had no embryo. This result was significantly different from the 2015 sample, for which 87 % of seed showed viable embryos, 10 % had low viability, 0 % was not viable and 3 % had no embryo. Seed germination was also significantly different between years (22 and 92 %) Pregerminative treatments did not improve germination. Seed germination and viability of H. perotensis significantly varied between years of seed collection. Rev. Biol. Trop. 65 (1): 153-165. Epub 2017 March 01.