The growth pattern of oat plants in winter as affected by the seasonal cold wind was investigated at Honjo experimental farm, Shimane University from December in 1975 to March in 1976.
The results obtained are as follows ;
1. The rate of leaf emergence and the number of tillers of the non hedged oat plants were respectively smaller than those of the hedged plants which were protected against the seasonal cold wind.
2. The relative growth rate(RGR) of the non hedged plants kept lower level throughout the test period than that of the hedged plants so that the increase of dry matter weight was smaller in the non hedged plants than in the hedged plants Due to the strong cold wind which blew at the speed of more than 3 m/sec. (daily mean value) for about 10 days in January, the RGR and the dry matter weight decreased remarkably.
3. The leaf area per plant decreased in the non hedged plants mainly due to the withering of leaves caused by the cold wind. Further, marked decrease in leaf area ratio(LAR) was detected in the non hedged plants as the cold wind had little effect on the growth of root.
4. The seasonal trend of net assimilation rate(NAR) was almost similar with that of RGR in either plot. The NAR of the non hedged plants was so affected by the strong cold wind in January that it was abnormally down to a minus value under the conditions.