Association of Eyespot Resistance in Wheat cv. 'Cappelle-Desprez' with Endopeptidase Profile

To test for the association of the eyespot of wheat cv. ‘Cappelle-Desprez’ with the structural gene encoding the isozyme Ep-A1, F₃, families from the cross ‘Cappelle-Desprez’ (resistant) X ‘Chinese Spring’ (susceptible) were selected on the basis of endopeptidase phenotype. Analysis of eyespot reaction showed that Ep-Alb homozygotes were associated with a higher level of resistance than Ep-Al a homozygotes. Thus selection of the Ep-Alb allelc should assure concurrent selection of at least a part of the eyespot resistance of ‘Cappelle-Desprez’.     

黄瓜叶片生长期间内肽酶活性和同工酶变化及其生化特性

研究了黄瓜自然生长期间叶片可溶性蛋白质降解、内肽酶活性及其同工酶的变化,并对叶片衰老后期粗提液内肽酶的基本生化特性进行了研究.结果表明,黄瓜叶片内肽酶活性在叶片伸出5 d时较低,叶片衰老后期(叶片伸出35 d)显著升高,Rubisco蛋白发生明显降解;叶片全展以后叶片蛋白质含量与内肽酶活性显著负相关.黄瓜叶片粗提液总内肽酶的最适pH为7.0,最适温度为40 ℃,内肽酶活性可被Ca2 、Zn2 、半胱氨酸等激活.内肽酶抑制剂试验显示,丝氨酸类型的内肽酶活性占内肽酶总活性的57%左右.采用以明胶为底物的内肽酶梯度凝胶电泳活性染色方法,检测到叶片中至少有4种内肽酶同工酶,各同工酶在叶片生长过程中出现的时间和活性大小不同,丝氨酸型内肽酶同工酶活性随叶片生长明显增强,暗示该类内肽酶在黄瓜叶片衰老过程中可能具有重要作用.     

Changes in Endopeptidase Activity during Photosynthetic Declination in Rice Leaf

Two japonica rice varieties, Wuyujing 3 and 97-7, were used to study the changes in contents of soluble protein, free amino acids and endopeptidase activity during photosynthetic declination. The content of soluble protein in flag leaf of cv. Wuyujing 3 was higher than that of cv. 97-7, but decreased rapidly in Wuyujing 3. Free amino acids in flag leaf and the thirteenth leaf of Wuyujing 3 started to increase 10 days before the turning point of photosynthetic declination (TPPD), while it occurred just 1-2 days before TPPD in the flag leaf and the thirteenth leaf of 97-7. During reversible phase of photosynthetic declination, endopeptidase activity remained at a low level and increased slightly only in the later part of this phase. Then it rose up rapidly at irreversible decline phase and reached a very high level. For Wuyujing 3, the change in endopeptidase activity in the thirteenth leaf was parallel to that in flag leaf. However, for 97-7, the rapid increase of endopeptidase activity in the thirteenth leaf started later than that of flag leaf. The results implied that the rate of protein breakdown and conversion to transportable nitrogen in leaves of 97-7 was slower than that in leaves of Wuyujing 3 during photosynthetic declination and it led to relatively lower seed setting rate and fully filling grains rate in 97-7. This may be one of the important reasons why 97-7 could not bring the high yield potentiality into play and the findings may be taken into consideration while breeding for high potential varieties in future.     

铝胁迫与小麦叶片的内肽酶活性及活性氧的产生

采用温室内自然光下小麦种子培养实验 ,研究了Al3 胁迫下和H2O2 处理时小麦幼苗叶片中的内肽酶活性和可溶性蛋白质的含量变化。结果表明 ,Al3 的胁迫和H2O2 处理均使小麦幼苗叶片中的内肽酶活性升高 ,可溶性蛋白质含量下降。Al3 的胁迫下 ,H 2O2 的清除剂ASA(抗坏血酸 )的加入使内肽酶活性明显下降 ,可溶性蛋白质的含量明显增加。Al3 胁迫下小麦幼苗叶片中的内肽酶活性升高和可溶性蛋白质含量下降的原因之一是产生了活性氧—H2O2。