摘要
我们测定了苹果幼果脱落期间磷化物含量的变化,以及脱落幼果与正常发育果实对P^(32)的吸收和转化。发现:脱落幼果中的无机磷含量较高;而其它糖磷酸醋、不稳定高能核苷酸和磷脂类等有机磷化物含量,则较发育果实降低很多。脱落幼果的ATP酶活性也比对照低。使用P^(32)进行示踪试验的结果看出,发育果实的果肉和种子中进入较多的P^(32);而脱落幼果吸收和运入的P^(32)少得多,失去了取得养分的生理优势。在脱落幼果与对照果实之间,P^(32)的转化也有明显差别。参入糖磷酸酯、高能核苷酸、磷脂、核酸和其它磷蛋白中的P^(32)显著降低。应用果肉和种子进行的试验,都得到类似结果。这些结果表明:由于脱落幼果养分供应不足,磷酸化作用水平降低,维持正常生命活动所必需的能量和原料亏缺,因此生长受阻,正常代谢作用不能进行,引起果实提前衰老,最后导致幼果脱落。
Changes of the phosphate compounds and the incorporation of radioactive pho- sphate into various phosphorus-containing compounds in both developing and absciss- ing fruits of‘Tompkins King' apple were investigated in 1962--1964. It was found that in abscissing fruits, the contents of inorganic phosphates were higher, while those of organic phosphates were lower than in developing fruits. The activity of ATPase was also lower in abscissing than in developing ftuits. Experiments with P^(32)-labeled phosphate indicated that the uptake of P^(32) by abscissing fruits was much less active than by developing fruits. There was more radioactivity in sugar-phosphates, high-energy nucleotides, phospholipids, nucleic acids and phosphoproteins in developing than in abscissing fruits. Similar results were ob- tained in fruit flesh and in seeds. The above results suggest that the shortage of food supply and the low level of phosphoryation in young fruit may cause suppression in fruit growth and alteration in normal metabolic pathway, which in turn may eventually bring about the senes- cence and abscission of the young fruits.
