In Komatsu city, a carrot-producing district in Ishikawa Prefecture, many carrot roots have been recently found to have shiny white belt-like swollen patches running lengthwise under the epidermis. This physiological disorder, so called "mimizubare-sho",has become a big problem for growers in this district. Kano reported in the previous paper that in roots bearing symptoms of mimizubare-sho the regions containing many cracks with air bubbles in the phloem parenchyma showed up a shiny belt. This paper reports the effect of sowing date on the root growth and the occurrence of mimizubare-sho.

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A cultivar of Japanese radish, 'Gensuke' is cultivated mainly in the sand dune regions in Ishikawa Prefecture. This radish is marketed at a high price in the central wholesale market in Kanazawa City during the period from the end of September to the middle of October. Therefore, the radish is sown from August 10 onwards, and furthermore, sowing during July is much needed among the growers in these districts. In this case, however, "hollow root" which has lengthwise hollownesses in the central part of the root induced by a physiological disorder (s) has been frequently observed. This gives much trouble to the growers in these districts. By the way, Takano observed the increases of meristematic tissues and rays of condcuting tissues in radish roots by naphthalene acetic acid (NAA). Therefore, for the purpose of the prevention of occurrence of hollow root, this research was carried out to investigate the influences of NAA on the growth and the occurrence of hollow root of 'Gensuke'.

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Several population parameters affecting the operational sex ratio of the damselfly, Cercion calamorum Ris, were investigated by mark-recapture methods in Kyoto, Japan. The sex ratios on emergence were even. There was no sexual difference in the daily survival rate during the maturation period; i. e., 0.837 for males and 0.833 for females. The length of the maturation period for most individuals were 10 days (males) and 12 days (females). The daily survival rate for the matured females were slightly higher than that for the matured males (0.861 vs. 0.839). The sex ratio (♀/♂) of the total matured individuals, which was obtained by calculating the above parameters, was 0.79. The arrival rate for the mature males at the reproductive area depended on the ambient temperature and therefore usually reached up to 1.0 on hot days in the summer. The matured females arrived at the reproductive area to oviposit at intervals of two or three days, suggesting that the daily arrival rate of the matured females at the reproductive area was, on the average, 0.29. Thus the operational sex ratio on the basis of a day, assuming that the arrival rate of matured males is 1.0, is estimated as 0.22. It was very close to the observed sex ratio; i. e., 0.23 (July) and 0.18 (Aug.). The sex ratio of the damselflies at the reproductive area on a census, that is, the sex ratio at a moment, was skewed still more toward males. This may reflect the sexual difference of the mean duration of staying at the reproductive area (414 min. for males and 126 min. for females). The expected sex ratio on a census added in the above parameter was also close to the observed one in August (0.066 vs. 0.065), but not to the ones in the early season probably because of the lower arrival rate of males at the reproductive area due to low temperature.

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[in Japanese]

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