Peroxidase activity and initial growth of ‘Barbosa’ peach on clonal rootstocks

Abstract In the peach nursery trees production, the use of rootstocks with unknown genetic identity obtained from peach seeds in the canning industry is frequent. The hypothesis tested was that there are rootstocks that express greater graft compatibility, enabling greater survival and growth, and that peroxidase activity can be used as indication of graft incompatibility. The aim of this study was to evaluate the survival and the peroxidase activity efficiency in identifying graft incompatibility and the trunk diameter growth of ‘Barbosa’ peach grafted onto 18 Prunus clonal rootstocks, propagated by herbaceous cuttings, compared to own-rooted scion trees. The experimental design was three randomized blocks, with one tree per plot. The first three vegetative cycles of trees conducted in double Y (5.0m x 2.0m) without irrigation were evaluated. The highest trunk diameter growth was provided by ‘Okinawa’, ‘Tsukuba-1’, ‘Tsukuba-2’, Mexico F1 and ‘Flordaguard’ rootstocks, without differing from own-rooted ‘Barbosa’ peach. Peroxidase activity differs by rootstock effect at the beginning of the dormancy period, and is higher than in vegetative growth, especially in interspecific graft combinations. Peroxidase activity is a biochemical indicator of stress, but should not be used alone and generalized to characterize graft incompatibility.

摘要：在桃树育苗生产中，从罐头工业副产物桃种子中获取遗传背景未知砧木的现象较为普遍。本研究验证的假说为：部分砧木可表现出更强的嫁接亲和性，从而提升嫁接成活率与植株生长势；过氧化物酶活性可作为嫁接不亲和性的指示指标。本研究的目的是评估‘Barbosa’桃接穗嫁接至18个经草本扦插繁殖的李属（Prunus）无性系砧木后的嫁接成活率、过氧化物酶活性对嫁接不亲和性的识别效能，以及接穗的干径生长情况，并以自根接穗植株作为对照。试验采用随机区组设计，设置3个重复区组，每小区定植1株苗木。试验对采用双Y形整枝（株行距5.0m×2.0m）且无灌溉条件下的植株前3个营养生长周期进行了观测。结果显示，‘Okinawa’、‘Tsukuba-1’、‘Tsukuba-2’、墨西哥F1及‘Flordaguard’砧木处理的植株干径生长量最高，其生长表现与自根‘Barbosa’桃无显著差异。在休眠期初期，过氧化物酶活性因砧木效应存在显著差异，且其活性水平显著高于营养生长期，在种间嫁接组合中这一差异尤为突出。过氧化物酶活性虽为胁迫相关的生化指示物，但不宜单独使用并泛化用于表征嫁接不亲和性。