Fourie J F, Holz G
Department of Plant Pathology, University of Stellenbosch, Private Bag X1, Matieland 7602, South Africa.
Plant Dis. 1998 Feb;82(2):165-170. doi: 10.1094/PDIS.1998.82.2.165.
Sugars in exudates from Harry Pickstone plum and Sunlite nectarine fruit and from pollen of weeds commonly found in orchards were determined by gas-liquid chromatography, and their effect on the development of Botrytis cinerea was determined in vitro and in vivo. Fructose, glucose, and sorbitol were the only sugars detected in exudates of immature fruit. They occurred at low concentrations, but their concentration generally increased as fruit ripened. Sucrose was first detected during maturation. In nectarine, an increase in sugar concentration, especially sucrose, was pronounced during the period of rapid cell enlargement, which occurred approximately 2 weeks before harvest. Absorbance readings of culture media amended with sugar indicated that the hexose sugars (fructose and glucose) and sucrose did not markedly influence growth of B. cinerea at concentrations below 0.22 and 0.12 mM, respectively. The hexose sugars caused a steady increase in growth when supplied at concentrations in excess of 0.44 mM, and sucrose caused a steady increase in growth at 0.23 mM. The stimulatory effect of fruit exudates on growth of B. cinerea on glass slides coincided with the period of rapid sugar release from the fruit and the shift in susceptibility to decay. Only fructose (1.72 mM) and glucose (0.72 mM) were detected in nectarine pollen exudates. Pollen exudates from weeds stimulated fungal growth and significantly increased the aggressiveness of the pathogen on plum and nectarine fruit when added to conidia during the last 4 weeks prior to the picking-ripe stage. The study showed that changes in the composition of nectarine and plum fruit exudates may contribute to the late-season susceptibility of these fruit to B. cinerea infection.
通过气液色谱法测定了哈里·皮克尔斯通李和阳光油桃果实渗出物以及果园常见杂草花粉中的糖分，并在体外和体内测定了它们对灰葡萄孢菌生长发育的影响。未成熟果实渗出物中仅检测到果糖、葡萄糖和山梨醇。它们的浓度较低，但一般会随着果实成熟而增加。蔗糖在成熟过程中首次被检测到。在油桃中，糖分浓度的增加，尤其是蔗糖，在快速细胞膨大期（收获前约2周）尤为明显。用糖改良的培养基吸光度读数表明，己糖（果糖和葡萄糖）和蔗糖在浓度分别低于0.22 mM和0.12 mM时，对灰葡萄孢菌的生长没有显著影响。当己糖浓度超过0.44 mM时，其会使生长稳定增加，而蔗糖在0.23 mM时会使生长稳定增加。果实渗出物对载玻片上灰葡萄孢菌生长的刺激作用与果实快速释放糖分的时期以及对腐烂易感性的变化相吻合。油桃花粉渗出物中仅检测到果糖（1.72 mM）和葡萄糖（0.72 mM）。在采摘成熟阶段前的最后4周，将杂草花粉渗出物添加到分生孢子中时，会刺激真菌生长，并显著增加病原菌对李和油桃果实的侵袭性。该研究表明，油桃和李果实渗出物成分的变化可能导致这些果实后期对灰葡萄孢菌感染的易感性。
