连作马铃薯植株库源关系及其对块茎产量的调节机理

Sink-source relationship of potato plants and its role involved in the reduction of tuber yield in continuous cropping system

甘肃中部沿黄灌区是国内重要的加工型马铃薯生产基地和种薯繁殖基地,但集约化生产带来的连作障碍已严重影响到产业的健康发展.为揭示马铃薯连作障碍机理,本研究通过田间试验,设置马铃薯连作年限为0~5年的处理,研究了马铃薯植株库容量、库活性和源活性对连作的响应特征及其对块茎产量的调节机制.结果表明:短期连作(1~2年)条件下块茎产量较非连作(0年)无显著变化,长期连作(3~5年)显著下降28.6%~32.8%,单薯质量降低是导致块茎产量下降的直接原因.长期连作马铃薯库容量较非连作显著降低38.4%~53.0%.长期连作导致块茎形成推迟,同时单薯干物质积累量降低.长期连作也显著降低马铃薯源活性,与非连作相比,株高、主茎分枝数、叶绿素含量和叶片干物质量均显著下降,根系形态发育受到抑制,根系活力显著下降28.6%~63.1%,叶片RuBP羧化酶和蔗糖磷酸合成酶活性分别显著下降52.6%~64.6%和26.3%~53.4%.长期连作条件下马铃薯源端生产性能降低导致同化产物减少,花后阶段向块茎的输入不足,降低块茎产量.库源关系失衡是甘肃中部沿黄灌区长期连作马铃薯产量大幅降低的原因.

The Yellow River irrigation area in middle Gansu Province is one of the main production bases for processing potato and potato tuber seeds in China. However, continuous potato cropping （ CPC）, resulting from intensive cultivation, has been affecting the sound development of the potato industry. A long-term field experiment was carried out in order to reveal the mechanisms of CPC ob- stacles. Five treatments, with different years of continuous potato cropping, were designed marking as 0-5 a, 0 a was maize-potato rotation, used as the control （CK）. The present study focused on how to change in sink size and sink activity conditions, especially their roles involved in as well as source activity of potato plants under CPC the reduction of tuber yield. There were no differences in tuber yield under short-term CPC （ 1-2 a） compared with CK, however, significant significant decline by 28.6%-32.8% occurred under long-term CPC （3-5 a）, which was mainly derived from the decline in fresh mass of each tuber. Compared with CK, long-term CPC significantly decreased sink size by 38.4%-53.0%. In addition, long-term CPC not only postponed the potato development progress, by postponing the formation and development of potato tubers, but reduced dry matter ac-cumulation in tubers as well. Long-term CPC significantly decreased source activity, showing that plant height, branch numbers per main stem, chlorophyll content, and dry-matter content of leaf were significantly lower than those of CK, besides, morphological development of root system was also restrained. Compared with CK, root vigor, ribulose diphosphate carboxylase （RuBP Case） and sucrose phosphate synthase （SPS） activities of leaves under long-term CPC significantly decreased by 28.6%-63.1%, 52.6%-64.6% and 26.3%-53.4%, respectively. Long-term CPC caused signi- ficant decline in production capability of source, consequently, reduced the production of assimila- tion product by a large margin, and contributed to the deficiency in translocation amount of assimi- lates into tuber during post-anthesis, which finally led to the reduction in tuber yield. In conclu- sion, the unbalance of sink-source relationship of potato plants was the main cause for CPC obsta- cles in the Yellow River irrigation area in middle Gansu Province.