应用缩节安(DPC)调控棉花株型的定位定量效应研究

缩节安(1,1-dimeyl piperidinium cloride, DPC)是棉花生产中广泛应用的植物生长延缓剂,其调控棉花茎枝生长的定位定量效应尚缺乏系统的量化研究。本研究 2013-2014 年在田间条件下分别于棉花现蕾期、盛蕾期后、盛花期前、盛花期后和打顶后单次应用不同剂量的 DPC,测量了 DPC 作用有效期内的棉花株高和主茎生长速率,探究了所有主茎节间及所有果节对 DPC 的响应。结果表明, DPC 处理对棉花主茎节间的影响范围为 N 节(应用 DPC 时的主茎节)以下 1~4 个和 N 节以上 0~6 个(打顶条件下),对果枝的影响范围为 N 节以下 1~11 个和 N 节以上 0~5 个,其中 N 节以下果枝受影响的果节多于 N 节以上果枝。将盛蕾期后和盛花期前 2 次应用 DPC 的效应叠加,其影响范围几乎可以覆盖全部主茎节间(果枝始节以上)和全部果节。DPC 应用剂量与其作用强度并不总存在较好的线性关系。DPC 的定位定量效应除了与应用时间和剂量有关,还受到温度、降水等环境条件和棉株生物量、源库关系的影响。

Location- and quantity-based effects of mepiquat chloride application on cotton plant-type

The plant growth regulator mepiquat chloride (MC; 1,1-dimethyl piperidinium chloride) has been successfully and worldwide used in cotton production. It has been known that MC application time decides its effect location and MC application rate decides its effect strength. However, there were less detailed information on the location- and quantity-based effects of MC on cotton stem and branches. In the present field study, MC was respectively applied at early squaring stage, after peak squaring stage, before peak blooming stage, after peak blooming stage and post-topping stage with a range of rates. We monitored plant height at three days interval during MC valid period, and measured all internodes of stem and fruiting branches prior to harvest. Under the condition of topping in late July, the overall effectiveness scope of MC (across different application times) on main stem ranged from the fourth internode below the uppermost node (named as N) to the sixth internode above N node. In terms of the effectiveness scope of MC on fruiting branches, it covered the 11 fruiting branches below N node and five branches above N node. In addition, the influenced internodes in most fruiting branches below N node were more than those above N node. When we overlaid the effectiveness scopes of MC application after peak squaring and before peak blooming, the effect was covered almost all internodes of both main stem (above the node of the first fruiting branch) and fruiting branches. Moreover, we found that there was not always a good linear relationship between MC rate and its effective strength. Besides application time and rate, the location- and quantity-based effects of MC may depend on temperature, rainfall, plant biomass and source-sink relationship.