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Hayashi T.,Hokkaido Research Organization Konsen Agricultural Experiment Station | Makino T.,Hokkaido Research Organization Konsen Agricultural Experiment Station | Sato N.,Hokkaido Research Organization Konsen Agricultural Experiment Station | Deguchi K.,Hokkaido Research Organization Animal Research Center
Plant Production Science | Year: 2015

Severe barrenness of maize (Zea mays L.) occurred in 2003 in eastern Hokkaido (Konsen region), one of the coldest areas in Japan. In many fields, tassels with few or no spikelets were observed in the cultivar widely grown in this region. The anthesis date was delayed 7 days from the silking date in the cultivar in the field at Konsen Agricultural Experiment Station (KAES). In July, when the tassels were developing at the 6- to the 9-leaf stage, the air temperature and sunshine hours were much lower in 2003 than in the average year. Therefore, we hypothesized that the barrenness resulted from these specific climatic conditions in 2003. To examine this assumption, we applied low temperature treatment (10ºC for 7 days) to the plants of the cultivar widely grown in this region in 2003 at around the 6- to 9-leaf stage in a greenhouse at KAES. Tassels were formed at the 7-leaf stage, and developed but they did not reach their full-size at the 8-leaf stage. The tassel length was shorter when the plants were subjected to the low temperature treatment, especially at the 8-leaf stage. The days from silking to anthesis was increased by the treatment in 2 of the 3 test years. The present results suggest that the cultivar is sensitive to the low air temperature at the 8-leaf stage for the development of tassels and may result in barrenness. © 2014, Crop Science Society of Japan. All right reserved.

Kamada H.,Japan National Agriculture and Food Research Organization | Matsui Y.,Hokkaido Research Organization Konsen Agricultural Research Center | Sakurai Y.,Hokkaido Research Organization Animal Research Center | Tanigawa T.,Hokkaido Research Organization Animal Research Center | And 12 more authors.
Placenta | Year: 2012

Fetal fibroblast cell culture from cotyledons of bovine placenta and animal experiments close to term were used to elucidate afterbirth release and factors missing in the signal transduction mechanism for retained fetal membranes (RFM) after delivery. In cell culture the addition of arachidonic acid (Ara) to the medium caused rapid release to free floating cell in the culture dish, accompanied by matrix metalloproteinase (MMP) activation, being consistent with previous in vivo observations, where a relation between MMP and fetal membrane release had been shown. Ara-induced cell floating was not inhibited by the addition of cyclooxygenase (COX) inhibitor, and not induced by the addition of PGF2α or PGE2 to replace Ara, while 12-lipoxygenase (12-LOX) metabolite of Ara, 12-oxo-eicosatetraenoic acid (12-oxoETE), strongly induced cell floating. In the animal experiments, 12-oxoETE injection to delivery-induced cows (n = 6) using prostaglandin (PG) and dexamethazone resulted in rapid release of fetal membranes. In cows with natural calf delivery, a 12-oxoETE peak (11.7-16.8 ng/ml) was observed in maternal blood plasma prior to release of fetal membranes. This investigation thus gives new indications for that the mediator for fetal membrane release is 12-oxoETE and not PG. © 2011 Elsevier Ltd. All rights reserved.

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