Stigma Constriction in Pearl Millet, a Factor Influencing Reproduction and Disease

The sequence of events during pollination in pearl millet isdescribed. Four or five hours after pollination with compatiblepollen a constriction region located in the fused stylodia,consisting of a collar of parenchymatous cells, becomes apparent.The structural integrity of the constriction region is lostwithin 6 h of pollination, thereby eventually isolating theovary from other pollen and also from ovary pathogens whichnormally enter throught the stigma. The constriction developsin unpollinated gynoecia 4–5 d after stigma emergence,thereby contributing to out-crossing in the protogynous commercialhybrid commonly grown in the semi-arid tropics. The potentialsignificance of a stigma constriction character in a wider botanicalcontext is discussed, particularly as it is a hitherto unrecognizedincompatibility barrier. Pennisetum americanum (L.), pearl millet, Sorghum bicolor (L.), sorghum, pollination, stigma constriction, ergot, protogyny, incompatibility barrier     

THE NORMAL INTESTINAL FLORA OF THE PIG II. QUANTITATIVE BACTERIOLOGICAL STUDIES

SUMMARY: Faecal and caecal samples from normal pigs were examined and the factors causing variations in bacterial numbers investigated by a dilution count technique. The range of variation for viable counts of faeces from normal pigs was 1.0 × 10⁸-9.9 × 10⁹/g and was in sufficiently close agreement with the results obtained with caecal contents to justify the use of faecal counts as an index of caecal numbers. The use of individually-fed pigs instead of group-fed pigs, with the consequent reduction of variations in environmental factors, appeared to reduce the variability of the counts. Changes in diet, either by incorporating grass meal or replacing all the animal protein by vegetable protein, did not affect the total numbers of organisms. The small variations in bacterial numbers regarded as significant by some of the earlier workers thus appear to be of little importance. Smears from high dilutions indicated that the predominant organisms were lactobacilli and streptococci; coli-aerogenes types were present in smaller numbers.