Abstract
The effect of powdery mildew infection on the $^{14}CO_2$ assimilation and metabolism of $^{14}C-$assimilates was studied with spring barley cultivars, susceptible Peruvian and adult-plant resistant Asse at the four-leaf stage. No consistent differences between Peruvian and Asse were revealed in $^{14}CO_2$ assimilation and metabolism of $^{14}C-$assimilates in healthy whole plants. In the two cultivars, $^{14}CO_2$ assimilation and translocation of assimilates decreased as the number of infected leaves increased. Despite the same infection intensity, $^{14}CO_2$ assimilation was less inhibited in Asse than Peruvian. Infection reduced the fixation of $^{14}CO_2$ in noninfected fourth leaves of Peruvian more severely than that of Asse. Infection of the lower 3 leaves also inhibited the incorporation of 14 C into carbohydrates such as fructose and glucose in noninfected fourth leaves and their translocation into leaf sheathes, the inhibitions being greater in Peruvian than Asse. In the infected third leaves, there was a reduction of 14 C-activity in carbohydrates, more $^{14}C-$labeled fructose and glucose being retained in Peruvian. The stimulation of $^{14}C-$organic acid synthesis in all plant organs was more pronounced in Peruvian than Asse. Powdery mildew markedly increased the incorporation of $^{14}C$ into amino acids in infected third and noninfected fourth leaves, but reduced their translocation to the leaf sheathes. A greater rise of $^{14}C-$ activity in some amino acids in the two leaves was found in Peruvian than Asse.
흰가루병에 대하여 감수성인 봄보리품종 Peruvian과 성체식물 저항성품종 Asse의 4엽기에서 흰가루병에 감염되었을 때 $^{14}CO_2$동화와 $^{14}C-$동화산물의 대사변화를 연구하였다. 건전식물에서는 Peruvian과 Asse간에 $^{14}CO_2$동화와 $^{14}C-$동화산물 대사에서 차이가 어 없었다. 감염된 엽수가 늘어남에 다라 이들 두 품종에서 $^{14}CO_2$ 동화와 동화산물의 이행량은 감소하였다. 감염정도가 같을때도 Asse보다 Peruvian에서 $^{14}CO_2$동화가 더 감소되었다. 흰가루병이 감염되지 않은 제4엽에서도 $^{14}CO_2$고장이 줄어들었고, Peruvian에서 더 줄었다. 아래 3엽이 감염되었을 때 감염되어 있지 않는 상위 제4엽에서 fructose, glucose등의 탄수화물로 $^{14}C$가 결합되는 것을 억제하였고 Asse보다 Peruvian에서 억제가 더 컸다. 감염된 제3엽에서도 탄수화물내에 $^{14}C$이 줄어들었으나 Peruvian에서 $^{14}C$로 표식된 fructose, glucose함량이 더 높았다. 모든 식물기관에 $^{14}C$-유기산합성이 촉진되었고 Asse보다 Peruvian에서 합성이 더 뚜렷하였다. 감염된 제3엽이나 건전제4엽에서 $^{14}C$이 아미노산으로 결합되는 것이 증가하였으나 엽초로 이동은 감소되었다. 이들 잎에서 어떤 $^{14}C$-아미노산은 Asse보다 Peruvian에 더 많이 축적되었다.
(Department of Plant Protection, College of Agriculture, Korea University)
;