Threshold modelling Lolium multiflorum seed germination: effects of Neotyphodium endophyte infection and storage environment

2012 ◽  
Vol 40 (1) ◽  
pp. 51-62 ◽  
Author(s):  
P.E. Gundel ◽  
M.A. Martínez-Ghersa ◽  
C.M. Ghersa
2007 ◽  
Vol 13 ◽  
pp. 277-280
Author(s):  
P.E. Gundel ◽  
J.B. Landesmann ◽  
M.A. Martínez-Ghersa ◽  
C.M. Ghersa

Neotyphodium endophytes are obligate vertically-transmitted endo-symbionts of Lolium multiflorum grass. Thus, the success of endophyte is tied with the success of the seed. Here we present results from experiments aiming to test the effect of endophyte infection on seed viability and germination vigour. Endophyteinfected and non-infected seeds of three L. multiflorum accessions were compared under accelerated ageing conditions (40ºC and ≈15% moisture content). Endophyte negatively affected seed viability and seed germination vigour in only one of the evaluated accessions. The effect of endophyte presence on seed quality in pasture grasses could depend on the population genetic background, and be related to direct or indirect effects of fungal infection on seed morphological or physiological characteristics. Keywords: Lolium multiflorum, Neotyphodium endophyte, seed quality, accelerated ageing


2011 ◽  
Vol 35 (6) ◽  
pp. 1141-1148 ◽  
Author(s):  
Rade Stanisavljevic ◽  
Dragoslav Ðjokic ◽  
Jasmina Milenkovic ◽  
Lana Ðukanovic ◽  
Vladeta Stevovic ◽  
...  

During post-harvest maturation, different species vary in the length of dormancy breaking or germination increases. Seed dormancy and slow seedling development often limit establishment of forage grass stands. Seed germination and seedling vigour of Italian ryegrass (Lolium italicum A. Braun, Synonym Lolium multiflorum L.), cocksfoot (Dactylis glomerata L.) and timothy (Phleum pretense L.) were observed after harvest and storage. After harvest in June, seeds were stored under standard storage conditions and sampled every 30 days after harvest (DAH), up to 270 DAH, and then every 60 days up to 990 DAH. At each date, seeds were tested for final germination percentage and for seedling vigour traits. Timothy seeds had a maximum germination (88%) and the best seedlings vigour at 90 DAH, which implies that early autumn (September-October) is the best sowing period for freshly harvested seeds of timothy. Timothy seed germination was poor from 270 DAH (73%). The best germination and vigour of Italian ryegrass and cocksfoot seedlings were between 270 and 330 DAH, which equates to spring sowing time (March-April) in the succeeding year. Cocksfoot and Italian ryegrass seeds maintained satisfactory germination levels up to 630 DAH (81%) and 810 DAH (81%), respectively. The data can serve for the determination of a proper storage duration management between harvest and sowing of the tested species under ambient conditions of south-eastern Europe.


2016 ◽  
Vol 44 (1) ◽  
pp. 199-206 ◽  
Author(s):  
J. Juan-Vicedo ◽  
J. Fernández-Pereira ◽  
S. Ríos ◽  
J.-L. Casas ◽  
I. Martín
Keyword(s):  

Author(s):  
Afonso Henrique Schaeffer ◽  
Diógenes Cecchin Silveira ◽  
Otávio Augusto Schaeffer ◽  
Nadia Canali Lângaro ◽  
Leandro Vargas

Botany ◽  
2009 ◽  
Vol 87 (1) ◽  
pp. 88-96 ◽  
Author(s):  
Pedro E. Gundel ◽  
M. Alejandra Martínez-Ghersa ◽  
Lucas A. Garibaldi ◽  
Claudio M. Ghersa

Neotyphodium endophyte fungi are vertically transmitted symbionts of cool-season grasses. The seed phase of the grass’ life cycle appears to be critical for the persistence of the fungus. Endophyte viability decreases faster than seed viability, but little is known of the effects of this endophyte on seed viability. The endophyte could affect seed viability through changes in water content. Here, we assessed the effects of the endophyte on seed viability, the differential survival of endophyte and seed, and the effects of infection on seed water content. Viability of endophyte-infected and noninfected seeds and endophyte were evaluated over a period of 729 d under 12 controlled environmental conditions. Seed viability was reduced by the infection at high temperature and high relative humidity, but not under other conditions. Moreover, endophyte viability decreased faster than seed viability only under high humidity or high temperature. Seed water content was not affected by endophyte presence. The proportion of viable infected seeds was mainly affected by the loss in endophyte viability and secondly by the differential survival of infected and noninfected seeds. Knowledge on the relative importance of these processes is critical to understand the factors affecting the efficiency of endophyte vertical transmission and the frequency of endophyte-infected plants.


2007 ◽  
Vol 13 ◽  
pp. 107-110
Author(s):  
M. Omacini ◽  
E.J. Chaneton ◽  
C.M. Ghersa

There is a growing recognition that endophyte effects on host plant traits may be propagated through food chains. We studied Neotyphodium occultans effects on soil nematode communities mediated by current and past patch occupancy by endophyteinfected Lolium multiflorum populations. A microcosm experiment was performed to evaluate whether abundance and diversity of nematodes at different trophic levels were affected by endophyte infection through rhizosphere-mediated or littermediated effects. We found that presence of endophyte-infected plants and their aerial litter both triggered a bottom-up trophic cascade enhancing the abundance of herbivorous and predaceous nematode taxa. Endophyte infection also increased overall nematode richness, mostly through changes induced at the highest trophic level in this soil food web. Our results suggest that fungal endophytes can modify the linkages between aboveand belowground community compartments, with potential consequences on plant patch dynamics. Keywords: soil food webs, Lolium multiflorum, Neotyphodium occultans, plant-soil feedback, after-life effects, indirect interactions, trophic cascades


2006 ◽  
Vol 84 (7) ◽  
pp. 1043-1051 ◽  
Author(s):  
Piippa R. Wäli ◽  
Marjo Helander ◽  
Oiva Nissinen ◽  
Kari Saikkonen

Neotyphodium endophytes are suggested to be mutualistic symbionts of grasses and regarded as potential biological plant protection agents. We examined the effects of the Neotyphodium endophyte of meadow ryegrass on snow molds in vitro with dual cultures of endophyte and Typhula ishikariensis , and on grass–snow mold interactions in vivo in a greenhouse and in a field experiment. In dual cultures, the endophytes formed an inhibition zone and retarded the growth of T. ishikariensis. In the field experiment, however, the endophyte-infected (E+) meadow ryegrasses were more susceptible to T. ishikariensis than the endophyte-free (E–) grasses. Endophyte infection increased the winter damage of grasses both in greenhouse and in field conditions. After winter, the growth of E+ grasses exceeded the growth of E– plants in the field experiment, indicating the marked tolerance of E+ grasses against winter damage. We detected differences in growth and pathogenesis between the different T. ishikariensis strains and found meadow ryegrass cultivar–endophyte status interaction in the growth of meadow ryegrasses, which highlight the effects of the genetic background of the participants on endophyte–grass–snow mold interactions.


2018 ◽  
Vol 40 (3) ◽  
pp. 246-252 ◽  
Author(s):  
Daniel Felipe de Oliveira Gentil ◽  
Sidney Alberto do Nascimento Ferreira ◽  
Elizabeth Rodrigues Rebouças

Abstract: Psidium friedrichsthalianum is a species whose fruit can be used to make juices, jellies/jams and sweets, and its seedlings serve as rootstocks with resistance to Meloidogyne spp. The aim of this study was to evaluate the performance of seeds of this species at different germination temperatures, and to verify the effects of different moisture levels on their storage in two experiments. In the first, six germination temperatures (15, 20, 25, 30, 35, and 40 ºC) were evaluated, and in the second, seeds with different moisture levels (15.4, 9.8, 9.0, 8.4, and 8.2%) were stored in sealed containers at 20 °C for 0, 1, 3, 6, 9, and 12 months. Seed germination was favored by temperatures of 20 ºC and 25 ºC, reaching 93% and 87%, respectively, along with the highest germination speed indexes (2.582% day1 and 2.568% day-1) and shortest germination times (37.9 and 36.9 days). Temperatures of 30 °C and 35 °C maintained the seeds quiescent, while 40 °C was lethal. In storage, the seeds tolerated desiccation to 8.2% moisture content and could be stored in sealed containers at 20 ºC for 12 months, with germination higher than 70%.


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