棉属诸种植株茸毛与其地理分布的关系

通过时棉属33个野生二倍体种和6个四倍体种植株茸毛与其分布地理纬度关系的分析看出,分布在南、北回归线间的棉种植株多茸毛;分布在南、北回归线附近的棉种植株稀毛或近光滑;分布在南回归线以南,北回归线以北的棉种植株光滑无毛。这种离开赤道愈远,棉种植株茸毛越少以至光滑的现象,体现了棉属诸种植株茸毛与地理分布的规律性。而那些不合这一规律的棉种,正是在分布、起源和进化上长期有争议的棉种。根据棉种植株茸毛与地理分布的规律性,笔者认为戴维逊氏棉是克劳茨基棉的变种;四倍体棉种是多元发生。

RELATIONSHIP BETWEEN CEOGRAPHICAL DISTRIBUTION AND PLANT PUBESCENCE IN GOSSYPIUM

The relationship between plant pubescence and the geographical distribution of 33 diploid and 6 tetraploid cottons is analysed in this paper. The plants of those species in Gossypium distributed in tropic areas between the Tropic of Cancer and Tropic of Capricorn appear to show high density pubescence;the plants of the species distributed near Tropic of Cancer and Tropic of Capricorn seem to show low density pubescence or almost smooth;the plants of the species distributed in the sub-tropic areas,south Tropic of Capricorn and north Tropic of Cancer show no pubescence. The farther from the equator,the less pubescence cotton plants have. This indicute the regularity of Plant pubescence in Gossypium with the geographical distribution. The species which seem not to suit this regularity are just the ones disputed on their origin,migration and evolution for along time.