scholarly journals Viability of Neotyphodium endophytic fungus and endophyte-infected and noninfected Lolium multiflorum seeds

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.


2018 ◽  
Vol 1 (1) ◽  
pp. 09-18
Author(s):  
Indra Dwipa ◽  
Muhsanati Muhsanati

Most of rice seeds experience after ripening problem which then result in seed dormancy. This kind of dormancy could be broken through various types of treatments, including storaging in dry place for certain period. This study was aimed to evaluate the combination between seed water content and storage duration to induce the seed germination of local genotype brown rice, Daro Merah. Various levels of seed water content (6-10, 11-15, 16-20 and 21-25 %) and storage duration (2, 4, 6 and 8 weeks) were evaluated to identify its effect on Daro Merah seed germination. Data were analyzed using two-way analysis of variance where significance were further proceeded using Duncan’s New Multiple Range Test with a p>0.05. The results showed that seed germination of Daro Merah reached 95 % at five days after seeding when the seed water content was maintained at 6-10% and stored for 8 weeks. After 14 days, the germination reached 99 % and most of the seeds showed some shoots emerged from the soil. Keywords: Brown rice, germination, seed water content, storage duration, Daro Merah



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



Crop Science ◽  
1969 ◽  
Vol 9 (2) ◽  
pp. 153-155 ◽  
Author(s):  
William R. Kneebone ◽  
Gary L. Major


2012 ◽  
Vol 170-173 ◽  
pp. 706-709
Author(s):  
Zhao Lin Jia ◽  
Shu Wang Yan ◽  
Zhi Liang Huo

By means of laboratory tests and theoretical calculation, the physical, mechanical properties and compaction mechanism of the wind-blown sand are studied to deal with the problem of how to use the wind-blown sand as roadbed materials. It is revealed that water content doesn’t affect the compressibility and the shear strength of the wind-blown sand obviously and the wind-blown sand can be compacted both in dry and wet conditions. The compaction curve of the ordinary fine sand is consistent with that of wind-blown sand and the main factors affecting the compaction properties are the grain composition, water content and compaction work.



2012 ◽  
Vol 36 (2) ◽  
pp. 229-235 ◽  
Author(s):  
Renata Conduru Ribeiro Reis ◽  
Claudinéia Regina Pelacani ◽  
Cimille Gabrielle Cardoso Antunes ◽  
Bárbara França Dantas ◽  
Renato Delmondez de Castro

Studies of seed physiological processes represent the starting point for the sustainable utilization of native or cultivated plant species from the caatinga biome for which germination studies are still scarce. In order to determine adequate methods for the conservation of Gliricidia sepium seeds, the physiological quality of propagules exposed to different conditions and times of storage were examined. Recently collected seeds of G. sepium were analyzed immediately, while the other sample was stored for three, six, nine, or twelve months in plastic or paper bags under refrigeration or at room temperature for further analysis. The germination rates of seeds from each storage regime were determined and these rates compared to their water content. It was observed that germination capacity was directly related to changes in seed humidity. Storing seeds in plastic bags yielded the best conservation, mainly when they were stored at low temperatures. However, even at temperatures near 25°C it was possible to prolong seed viability when their water content was controlled through the use of impermeable packing.



2013 ◽  
Author(s):  
J. Rick Griffin ◽  
James R Johnstone ◽  
Terry E Cotter ◽  
Ashleigh E O'Brien


1933 ◽  
Vol 1 (3) ◽  
pp. 99-102
Author(s):  
P. G. McVetty

Abstract This paper discusses the various methods which have been proposed to determine safe working stresses for high-temperature service. The question of the stability of alloys during the test and in subsequent service is considered, with particular emphasis upon probable changes in creep characteristics during long exposure to stress and temperature. It is shown that published data in general do not admit of extrapolation, and that attempts to estimate total creep in service from such data are not usually satisfactory. The author stresses the need for more fundamental study of the laws governing creep rather than creep tests of many different materials.



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