Clearwater Michael J, Seleznyova Alla N, Thorp T Grant, Blattmann Peter, Barnett Andrew M, Lowe Russell G, Austin Paul T
Horticulture and Food Research Institute of New Zealand, Te Puke Research Center, RD 2 Te Puke, New Zealand.
Tree Physiol. 2006 Apr;26(4):505-15. doi: 10.1093/treephys/26.4.505.
Patterns of shoot development and the production of different types of shoots were compared with scion leaf area index (LAI) to identify how eight clonal Actinidia rootstocks influence scion development. Rootstocks selected from seven Actinidia species (A. chrysantha Merri., A. deliciosa (A. Chev.) C. F. Liang et A.R. Ferguson, A. eriantha Benth., A. hemsleyana Dunn, A. kolomikta (Maxim. et Rupr.) Maxim., A. kolomikta C.F. Liang and A. polygama (Sieb. et Zucc.) Maxim.) were grafted with the scion Actinidia chinensis Planch. var. chinensis 'Hort16A' (yellow kiwifruit). Based on an earlier architectural analysis of A. chinensis, axillary shoot types produced by the scion were classified as short, medium or long. Short and medium shoots produced a restricted number of preformed leaves before the shoot apex ceased growth and aborted, resulting in a 'terminated' shoot. The apex of long shoots continued growth and produced more nodes throughout the growing seasons. Mid-season LAI of the scion was related to the proportion of shoots that ceased growth early in the season. Scions on low-vigor rootstocks had 50% or less leaf area than scions on the most vigorous rootstocks and had a higher proportion of short and medium shoots. On low-vigor rootstocks, a higher proportion of short shoots was retained during pruning to form the parent structure of the following year. Short parent shoots produced a higher proportion of short daughter shoots than long parent shoots, thus reinforcing the effect of the low-vigor rootstocks. However, overall effects of rootstock on shoot development were consistent regardless of parent shoot type and nodal position within the parent shoot. Slower-growing shoots were more likely to terminate and scions on low-vigor rootstocks produced a higher proportion of slow-growing shoots. Shoot termination also occurred earlier on low-vigor rootstocks. The slower growth of terminating shoots was detectable from about 20 days after bud burst. Removal of a proportion of shoots at the end of bud burst increased the growth rate and decreased the frequency of termination of the remaining shoots on all rootstocks, indicating that the fate of a shoot was linked to competitive interactions among shoots during initial growth immediately after bud burst. Rootstock influenced the process of shoot termination independently of its effect on final leaf size. Scions on low-vigor rootstocks had a higher proportion of short shoots and short shoots on all rootstocks had smaller final leaf sizes at equivalent nodes than medium or long shoots. Only later in the development of long shoots was final leaf size directly related to rootstock, with smaller leaves on low-vigor rootstocks. Thus, the most important effect of these Actinidia rootstocks on scion development occurred during the initial period of shoot growth immediately after bud burst.
将接穗的新梢发育模式和不同类型新梢的产生情况与接穗叶面积指数（LAI）进行比较，以确定8种猕猴桃无性系砧木如何影响接穗发育。从7个猕猴桃物种（金花猕猴桃、美味猕猴桃、毛花猕猴桃、长叶猕猴桃、狗枣猕猴桃、葛枣猕猴桃和软枣猕猴桃）中选出砧木，与中华猕猴桃品种‘Hort16A’（黄心猕猴桃）接穗进行嫁接。基于之前对中华猕猴桃的结构分析，将接穗产生的腋生新梢类型分为短梢、中梢和长梢。短梢和中梢在梢尖停止生长并败育之前，产生的叶原基数量有限，形成“终止型”新梢。长梢的梢尖持续生长，并在整个生长季节产生更多节位。接穗的季中叶面积指数与季节早期停止生长的新梢比例有关。低活力砧木上的接穗叶面积比活力最强的砧木上的接穗叶面积少50%或更少，且短梢和中梢的比例更高。在低活力砧木上，修剪时保留较高比例的短梢以形成下一年的母枝结构。短母枝产生的短子梢比例高于长母枝，从而强化了低活力砧木的影响。然而，无论母枝类型和母枝上的节位如何，砧木对新梢发育的总体影响是一致的。生长较慢的新梢更有可能终止生长，低活力砧木上的接穗产生的生长较慢的新梢比例更高。低活力砧木上的新梢终止也更早发生。从萌芽后约20天开始，就可以检测到终止生长新梢的生长较慢。在萌芽末期去除一部分新梢，可提高所有砧木上剩余新梢的生长速率，并降低其终止频率，这表明新梢的命运与萌芽后初期生长过程中新梢之间的竞争相互作用有关。砧木对新梢终止过程的影响独立于其对最终叶片大小的影响。低活力砧木上的接穗短梢比例更高，并且在所有砧木上，相同节位的短梢最终叶片大小比中梢或长梢小。只有在长梢发育后期，最终叶片大小才与砧木直接相关，低活力砧木上的叶片较小。因此，这些猕猴桃砧木对接穗发育的最重要影响发生在萌芽后新梢生长的初期阶段。
