喷施多效唑对糜子生长及光合特性的影响

Effects of Spraying Paclobutrazol on Growth and Photosynthetic Characters of Broomcorn Millet

为了明确多效唑喷施时期和浓度对糜子生长及光合特性的影响,以‘齐黍1号’为研究材料,采用随机区组设计,于糜子分蘖期、拔节期和孕穗期叶面喷施150、300、600和1200mg/L多效唑,以清水作对照。结果表明,叶面喷施多效唑可以改变糜子植株茎秆的形态特征,使株高降低、茎粗增加,从而增强植株的抗倒伏能力。在同一喷施时期,随施药浓度的增加,糜子主茎高逐渐降低,节间增粗,抗倒伏力逐渐增强。在糜子生育时期喷施适宜浓度的多效唑能增加糜子的净光合速率、蒸腾速率及相对叶绿素含量,且随着多效唑浓度的增加均呈先增加后降低的变化趋势;在适宜时期喷施多效唑可提高糜子主穗重及主穗粒重,使糜子显著增产,且分蘖期喷施效果优于拔节期和孕穗期,但浓度过高时会降低增产效果。综合分析,在本试验条件下,分蘖期喷施300mg/L的多效唑可以有效增强糜子的抗倒伏能力及光合指标,提高产量,是较适宜糜子的防倒增产栽培措施。

In order to investigate effects of paclobutrazol spraying time and concentration on growth and photosynthetic characters of broomcorn millet,Qishu 1 was used as materials,and the randomized block design was conducted.Four concentrations(150,300,600,1200 mg/L)of paclobutrazol were applied on broomcorn millet,at the tillering,elongation and booting stage,with distilled water as control.The results showed that spraying of paclobutrazol could change morphological traits of stalk,decrease plant height,increase stem diameter and lodging resistance.The appropriate concentration of paclobutrazol in the growth period of broomcorn millet could promote the net photosynthetic rate,transpiration rate and relative chlorophyll content of broomcorn millet,and the three indexes all increased firstly and then decreased with the increase of paclobutrawl concentration.Spraying paclobutrazol could increase the weight of main spike,grain weight of main spike,and grain yield,and the effect of spraying at tillering stage was better than that of jointing stage and booting stage,but when the concentration was too high,the effect of increasing yield reduced.According to the comprehensive analysis,spraying 300 mg/L paclobutrazol at tillering stage could effectively enhance lodging resistance and photosynthetic indexes of millet,which is a suitable cultivation measure for preventing lodging and increasing yield.