桑樹冬芽休眠の生理学的研究
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概要
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1) This experiment was carried out to ascertain the Test-period of mulberry-tree in Kagoshima. The materials were 4-, 5-, and 33-year-old plants of the form, Shukakuichi and the form, Kairyowasejumonji, with different prunning period. It is well known that the dormany (in a wide sense) of mulberry-tree exists during early autumn to winter and is divided into (automatic) rest and (heteronomic) quiescence. Adding to this, it was recognized by the author that the rest began seemingly at the end of September, subsequently became deeper through the later part of October into November, turning gradually into quiescence from the beginning of December, and at last, after the end of January the preparation of bud-sprout became almost complete. The rest-period of the form, Shukakuichi, was nearly the same with that of the form, Kairyowasejumonji, but the degree of rest-condition was deeper in the former than in the latter. Differences of tree-age, 4- and 33-year-old plants, and of cutting-period, (spring and early summer) gave no influence upon the rest-condition. 2) The author performed the leaf-spray of α-naphthalene acetic acid (NAA, 0.02%), maleic hydrazide (MH, 0.1%) and urea (0.5%) solutions on the mulberry tree, during the period from the end of August to early September ; namely, the period shortly before the bud of mulberry tree falls into the rest : and observed the effect of these treatments upon the rest-period of the bud of the tree. In the early rest-period, the bud-sprouting-rate of the tree treated with NAA or MH was lower than that of the non-treated sample, indicating the inhibiting effect of these 2 solutions ; on the other hand, the bud-sprouting-rate sprayed with urea was higher, showing the sprout-promoting-effect to some extent. The deepest rest-periods of the NAA-treated and urea-treated mulberry trees retarded 10 days and 20 days, respectively ; compared with those of the non-treated ones. Small wattles cut from the trees of several different stages of the rest-period were immersed in water and in 5 as well as in 50 p.p.m. solution of -indole acetic acid (IAA), α-naphthalene acetic acid (NAA) and 2,3,5,-triiodobenzoic acid (TIBA) for 24 hours in room temperature. The sprouting-rates induced by water as well as by 5 p.p.m. solutions of different chemicals, except NAA, were nearly identical with each other ; however, NAA inhibited the bud-sprouting in the early period of the rest. All the 50 p.p.m. solutions inhibited the bud-sprouting ; while the bud immersed in water, was promoted to sprout slightly better, compared with the bud not immersed in water. The effect of the leaf-cutting, carried out in 3 different periods (on July 19,August 8 and September 18), leaving the growing-point and uppermost 4-5 leaves as they were, upon the rest-condition of the tree was also observed. The leaf-cutting on July 19 as well as on September 18 gave little effect upon the rest, but concerning the mulberry, whose leaves had been removed off on August 8,the deepest rest-period was delayed for 20 days as compared with the case of the intact tree ; furthermore, its sprouting-rate in the "tominki"(heteronomic quiescence) was markedly lowered. From these results it may be said that leaf-cutting in about August, exerted a worse influence upon mulberry tree than that carried out in about July as well as in about September. 3) By measuring the variation in the contents of reducing sugar, total sugar and saccharose in mulberry winter buds in the rest-period as well as before and after the term, it was ascertained that there was a small peak of the content, on about the 20 th of October, i. e. in the deepest dormant period. The contents of total sugar and saccharose began to increase in real, from about the 20th Of November, getting to the maximum amount, on the 30th of January ; but decreased from that time to the sprouting period of winter-buds. The contents of the reducing sugar gave a large peak on the 11th-20th of January, and there
- 鹿児島大学の論文
- 1971-09-25