不同砧木對柑桔果實生理及形態變化之研究

Effects of Different Rootstocks on the Physiological and Morphological Changes of Citrus Fruits

翁仁祿(Jen-Lu Weng)

《中國園藝》 19卷5期 (1973/09) Pp. 319-327

摘要

本研究以酸桔，Cleopatra，廣東檸檬及枳殼等四種砧木嫁接椪柑及桶柑，調查各種砧木對所產果實發育情形，成熟度及果皮絨層組織崩壞程度之影響，以求各砧木柑桔果實之最適採取期。
四砧木中枳殼砧因根羣分佈較淺，受降雨量之影響最爲顯著，果實生長率和降雨量成正相關關係。果皮之發育略與果肉之生長速度成反比例，果肉生長旺盛時由果實內部向外産生之壓力較強，果皮較薄。降雨量少果實生長停頓時卽發生相反現象。果實成熟期之果皮以枳殼砧爲最厚。椪柑果實果汁之含糖量以12月間爲最高，含酸量以1月間爲最低，四砧木中枳殼砧果實果汁之含糖，酸量均高，風味最佳。桶柑果實果汁之含糖量以採取放置2週後之2月上旬最高。含酸量卽隨藏日數之增加，而逐日降低。
椪柑果實中以Cleopatra砧果實果皮albedo組織之崩壞速度爲最早，酸桔砧果實爲最遲，前者於10月下旬，後者於12月下旬開始崩壞。桶柑果實果反albedo組織之崩壞時期最遲，不同砧木果實間之果皮albedo細胞之肥大速度雖依採用砧木種類而有異，但均以月下旬爲崩壞始期。最適採取期椪柑爲12月間、桶柑在12月下旬至1月中旬之間，但枳殼砧椪柑及桶柑果實果汁成份濃厚且成熟較早，可提早採收期。

並列摘要

Loose skin mandarins like ponkan and tonkan can be easily peeled when mature, a property desired by consumers and canners alike. However, over puffiness IS considered a defect because it causes uneholesome appearoma and increased handling losses of tile fruit. Owing to the warm climate in the fall and winter seasons in Taiwan, albedo cells on the citrus fruit skin enlarge very rapidly, sometimes causing over puffiness of the fruits. Under this study, ponkan and tonkan fruits on various kinds of rootstocks namely: sunki, cleopatra mandarin, lunpar lime and triforiate orange, were observed and their development maturation and albedo tissue corruption at different stages and seasons carefully studied. Some of the important findings are summarized as follows:
1. The growth rate of fruit was significantly influenced by rainfall More rainfall accelerated the fruit growth, while the reverse is true with less rainfall. Such kind of influence on mandarin fruit grafted on trifoliate orange rootstock was particularly obvious because of the shallowness of root distribution of the trifoliate orange rootstock in the soil.
2. The growth rate pf peel was somewhat conversely relater to that of flesh. The rapid growth of the flesh gave rise to a pressure in the inner surface of the peel and hence, caused thinner peel growth. Interrupted growth of flesh caused by insufficient rainfall, on the other hand, increased the thickness of peel. When mature mandarin fruit on trifoliate orange rootstock thicker peel than that on other kinds of roostocks.
3. The sugar content of ponkan fruit suice was highest in December and the acid content was lowest in January. Ponkan fruit grown on the trifoliate orange rootstock had higher suger and acid contents and better eating quality than that grown on other kinds of rootstocks. Tonkan fruit juice had the highest sugar content in February when the fruit had been stored for two weeks and its acid content diminished during the storage period.
4. Accompanying the fruit growth, albedo cells on the peel were observed to have been enlarged, their shape changed, intercellular spaces incresed, then sponge like albedo tissue formed and finally corrupted. Albedo tissue of ponkan fruit on the cleopatra mandarin rootstock began to corrupt at an earliest date (in late October) and that on the sunki rootstock at the latest (in late December). Albedo cells of tonkan fruits on different rootstocks had different rates of enlargement. The corruption of albedo tissue of tonkan began in late December.
(5). Ponkan had the highest soluble solid content in juice in December when the albedo tissue had not yet significantly corrupted. Therefore December is considered to be the most adequate time for harvesting ponkan. Judging from the facts that tonkan fruit had the highest sugar content in early February and that albedo tissue began to corrupt from late December, the adequate harvesting time may fall during the period from late December to the middle of January. Both ponkan and tonkan grafted on trifoliate orange rootstocks seemed to mature earlier and have more concentrated fruit juice than the same kind of fruit on other rootstocks and hence they can be harvested earlier.