Factors influencing the germination of macroconidia and secondary conidia of Claviceps africana

2002 ◽  
Vol 53 (10) ◽  
pp. 1087 ◽  
Author(s):  
Shamsul A. Bhuiyan ◽  
Victor J. Galea ◽  
Malcolm J. Ryley ◽  
David Tay ◽  
Allan T. Lisle
Keyword(s):  
Optimum Temperature ◽  
Flower Extract ◽  
Extract Agar ◽  
Factors Influencing ◽  
Water Potentials ◽  
Secondary Conidium ◽  
Claviceps Africana ◽  
Conidium Germination ◽  
Temperature Time

The influences of temperature, time, and moisture on the germination of macroconidia and secondary conidia of Australian isolates of Claviceps africana were studied in vitro. The optimum temperature for germination of both macroconidia and secondary conidia of C. africana was 20°C. Although germination of macroconidia ceased near 31°C, approximately 30% of secondary conidia germinated at 37°C after 48 and 72 h of incubation. Sorghum flower extract agar stimulated macroconidium and secondary conidium germination, irrespective of temperature. Germination of macroconidia and secondary conidia on water agar started after 4 h of incubation at 20°C, reaching a maximum after 16–24 h and 14 h, respectively. Maximum germination of both macroconidia and secondary conidia was at ≥ –5 bars at 20°C. Germination of secondary conidia ceased at –35 bars, whereas macroconidia germinated at water potentials as low as –55 bars at 20°C.

scholarly journals Effects of Humidity on the Development of Grapevine Powdery Mildew

2003 ◽  
Vol 93 (9) ◽  
pp. 1137-1144 ◽  
Author(s):  
J. E. Carroll ◽  
W. F. Wilcox
Keyword(s):  
Powdery Mildew ◽  
Management Practices ◽  
Absolute Humidity ◽  
Uncinula Necator ◽  
Disease Development ◽  
Optimum Temperature ◽  
Test Range ◽  
Grapevine Powdery Mildew ◽  
Conidium Germination

The effects of humidity on powdery mildew development on grape seedlings and the germination of Uncinula necator conidia in vitro were examined. Studies were conducted at an optimum temperature of 25 ± 2°C. Disease on foliage was markedly affected by humidity levels in the test range of 39 to 98% relative humidity (RH), corresponding to vapor pressure deficits (VPD) of 1,914 to 61 Pa. Incidence and severity increased with increasing humidity to an optimum near 85% RH, and then appeared to plateau or decrease marginally at higher values. Conidial density and chain length also were proportional to humidity, but were influenced less strongly. There was a strong, positive linear relationship between humidity level and frequency of conidium germination with RH treatments of ≤84%. However, germination frequency fell sharply at RH levels above a mean of 87%. All measures of humidity were equally accurate in predicting germination responses; however, VPD was slightly more effective than RH in accounting for effects on disease development and pathogen sporulation, and both were more effective than absolute humidity. Humidity appears to play a significant role in grapevine powdery mildew epidemiology, confirming the benefits of management practices to avoid and mitigate high humidity in the vineyard canopy.

Factors Influencing in Vitro Rumen Cellulose Digestion

1956 ◽  
Vol 15 (4) ◽  
pp. 1180-1187 ◽  
Author(s):  
C. N. Huhtanen ◽  
R.F. Elliott
Keyword(s):  
Cellulose Digestion ◽  
Factors Influencing

The effects of Pueraria thomsonii flower extract on estrogenic activity, osteoblast differentiation and osteoclast formation in vitro

Maturitas ◽  
2017 ◽  
Vol 100 ◽  
pp. 189
Author(s):  
Hosong Cho ◽  
Boyoung Lee ◽  
Wonkyung Lee ◽  
Soonran Song ◽  
Junman Lim ◽  
...  
Keyword(s):  
Osteoblast Differentiation ◽  
Estrogenic Activity ◽  
Osteoclast Formation ◽  
Flower Extract

scholarly journals Infection Potential of Pleospora allii and Evaluation of Methods for Reduction of the Overwintering Inoculum of Brown Spot of Pear

Plant Disease ◽  
2006 ◽  
Vol 90 (12) ◽  
pp. 1511-1516 ◽  
Author(s):  
Isidre Llorente ◽  
Albert Vilardell ◽  
Emilio Montesinos
Keyword(s):  
Biological Control ◽  
Brown Spot ◽  
Control Methods ◽  
Optimum Temperature ◽  
Chemical Methods ◽  
Stemphylium Vesicarium ◽  
Mechanical Methods ◽  
Pleospora Allii ◽  
Evaluation Of Methods

The capacity for germination and pathogenicity to pear leaves of ascospores of Pleospora allii, the teleomorph of Stemphylium vesicarium, causal agent of brown spot of pear, were studied in vitro. Most ascospores germinated within 1 h at temperatures between 15 and 20°C, and the optimum temperature for germination was 18.9°C. Infections developed on wounded and non-wounded detached pear leaves, but were more frequent on wounded leaves. The minimum infective dose was one ascospore per wound. Biological, chemical, and mechanical methods for decreasing overwintering inoculum of P. allii were evaluated. Ascospores were discharged from March to May, depending on the orchard and year. Leaf shredding or removal were the most effective methods of reducing overwintering inoculum. Biological control methods based on application of Thichodermasp. formulations were partially effective. Chemical methods based on copper and urea treatments were ineffective.

Factors influencing monocyte recognition of human erythrocyte autoantibodies in vitro

Transfusion ◽  
1982 ◽  
Vol 22 (5) ◽  
pp. 355-358 ◽  
Author(s):  
JS Hunt ◽  
ML Beck ◽  
GE Tegtmeier ◽  
WL Bayer
Keyword(s):  
Human Erythrocyte ◽  
Factors Influencing
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