Occurrence of <Emphasis Type="Italic">Phaeoacremonium</Emphasis> spp. and <Emphasis Type="Italic">Phaeomoniella chlamydospora</Emphasis> in grape propagation materials and young grapevines

During a 6-year study, grapevine propagation materials and young grapevines were analysed to evaluate the presence of internal wood discolouration and the occurrence of fungal species involved in Petri disease. The intensity of wood discolouration increased with the ageing of the plants. The maximum incidence of dark streaks was observed in the rootstock while necrosis originating from buds or nodes were notably present in the trunk and cordon of older vines. In contrast, the highest levels of brown-red halo symptoms, defined as discoloured areas around the pith, were recorded in the early growth stages. Phaeoacremonium spp. and Phaeomoniella chlamydospora were usually isolated from the rooted-grafts and the 3-year old plants, respectively. The number of infected grapevines increased with age. Most of the P. chlamydospora strains were isolated from dark streaks or dots, while Phaeoacremonium spp. were detected in brown-red halo symptoms and other symptomatic or asymptomatic wood. The greatest incidence of the two fungal taxa was recorded in the lower parts of the grapevine, including the roots and rootstock.     

落叶松高砧嫁接技术

介绍了落叶松高砧嫁接的时间、方法及嫁接苗管理,并分析了砧木高度、地径与接穗高生长的关系.     

缺钾诱导早衰条件下应用嫁接技术研究根-冠互作对棉花下胚轴解剖结构的影响

缺钾诱导早衰条件下,根-冠互作对棉花叶片早衰的调节包括地上部主导型和根系主导型。本研究主要观察缺钾条件下2种根-冠互作类型单接穗单砧木(I型)和双接穗单砧木(Y型)嫁接接穗下胚轴的解剖结构,并判断其与下胚轴木质部中CTK和ABA的流量是否有关。结果表明,地上部主导型I型嫁接接穗下胚轴解剖结构与砧木品种更为相似,与其木质部CTK和ABA的流量主要受地上部调节不符;Y型嫁接2个不同品种接穗之间下胚轴解剖结构的差异与其木质部CTK和ABA流量的差异虽然具有相关性,但可能是一种伴生现象。根系主导型I型嫁接砧木对接穗的影响很大,但这与砧木对接穗下胚轴木质部CTK和ABA流量的调节可能也是一种伴生现象;Y型嫁接2个不同接穗之间下胚轴解剖结构差异较大,与二者之间CTK和ABA流量无显著差异的结果不符。因此,棉花叶片早衰2种根-冠互作类型接穗下胚轴解剖结构与其木质部中CTK和ABA的流量无关。此外,无论是地上部主导型还是根系主导型,2个品种自身嫁接的接穗下胚轴结构差异在Y型嫁接与I型嫁接中不一致,可能与Y型嫁接的2个接穗之间存在冠-冠互作有关。