Abstract:

In order to understand the effect of water stress on the internode length of sugarcane， 8 sugarcane varieties developed home and abroad with different drought tolerance were planted in barrels and in fields. Under the conditions of artificial water stress and natural rain-fed condition in fields， the plant height， stalk diameter and internode length of sugarcane were investigated during the harvest period. The results showed that， under the conditions of artificial water stress， drought caused 88% of sugarcane varieties to grow shorter， and the stem diameter of sugarcane decreased first and then increased （stem diameter of +13~+6 node） due to the artificial water stress and rehydration， and the internode length became significantly shorter and then increased. Under natural rain-fed condition infields， the plant heights of 8 sugarcane varieties in 2 test bases were 2.7~3.4 m in 2 years. Influenced by drought climate and other conditions， the relatively ideal sugarcane varieties judged by plant height were ‘ROC1’ ‘ROC22’ ‘GT21’ and ‘CP80-1827’. Compared with artifical water stress， natural drought led to the reduction of sugarcane stem diameter with the most details in +7 leaf stems， the internode length becomed shorter and the shortest internode appeared in +8 and +9 leaf stems. Under the conditions of artificial water stress， the varieties with strong drought tolerance showed the high internode water stress index （IWSI）and internode water stress recovery index （IWSRI）. While the varieties with strong drought tolerance showed the high IWSI and low IWSRI under natural rain-fed conditions in fields. In terms of recovery index， the normal internode length after drought rewatering was longer than that before drought， which showed that the moderate drought stimulated the growth of sugarcane. In general， water stress leaded to shorter plant height， smaller stem diameter and shorter internode length of sugarcane. The IWSI and IWSRI could be used to understand the growth difference of different sugarcane varieties stem nodes in response to water stress， and they could be as indexes to evaluate the drought tolerance of sugarcane varieties under drought conditions. The research on sugarcane drought tolerance could not completely rely on artificial water control to simulate drought， and the breakthrough research on sugarcane drought tolerance should focus on natural drought in field.

Key words: sugarcane, water stress, stem nodes

摘要：

为了解干旱胁迫对甘蔗节间长度的影响，连续2年对国内外8个不同抗旱能力的甘蔗品种采用桶栽和大田种植，在人为控水和大田自然干旱胁迫条件下，于甘蔗收获期调查甘蔗株高、茎径及节间长度。结果表明，在桶栽人为控水条件下，干旱导致88%的甘蔗品种株高变矮；受干旱控水、复水影响，甘蔗茎径呈先变小后增大的趋势（+13~+6节茎径），节间长度明显变短后再增长。在自然干旱水分胁迫下，2个试验基地 8个甘蔗品种2年的株高为2.7~3.4 m；受干旱气候及其他条件影响，株高相对理想的甘蔗品种为‘ROC1’‘ROC22’‘GT21’和‘CP80-1827’。同人为控水相比，自然干旱导致甘蔗茎径变小，最细节出现在+7叶茎；节间长度变短，最短节出现在+8和+9叶茎。在人为控水干旱条件下，抗旱性较强的甘蔗品种节间旱胁迫指数和节间旱胁迫恢复指数相对较高。在大田自然干旱条件下，抗旱性较强的甘蔗品种表现为相对较高的节间旱胁迫指数和较低的节间旱胁迫恢复指数。从恢复指数来看，干旱复水后的正常节间长度均大于干旱前的正常节间长度，表明适度的干旱刺激了甘蔗生长。总体来说，水分胁迫导致甘蔗株高变矮、茎径变小、节间长度变短，节间旱胁迫指数和节间旱胁迫恢复指数可作为甘蔗茎节应对干旱胁迫的指标，以此来评价甘蔗品种的抗旱性具有一定的参考价值。甘蔗的抗旱性研究不能完全依赖人为控水的模拟干旱，其抗旱能力的整体评价需要围绕大田自然干旱开展。

关键词: 甘蔗, 干旱胁迫, 茎节