【目的】探究叶片喷施不同质量浓度的多效唑(PP333)、矮壮素(CCC)、烯效唑(S3307)对板栗苗枝条生长动态及叶片内非结构性碳水化合物(NSC)[可溶性糖(SS)和淀粉(ST)]含量的影响,为板栗化学调控提供理论依据。【方法】以备选砧木3年生板栗‘燕山早丰’(Castanea mollissima‘Yanshanzaofeng’)苗为试验材料,选择15%多效唑可湿性粉剂、50%矮壮素水剂、5%烯效唑可湿性粉剂配置溶液,在花芽分化期选择天气晴朗无风的早晨分别喷施多效唑(50、100、150 mg/L)、矮壮素(100、150、200 mg/L)和烯效唑(30、60、90 mg/L),以喷清水为对照(CK),各处理进行整株喷施,直至叶面布满水珠而不滴水为止。试验采用单因素完全随机区组设计,单株为1个小区,每个处理设5个重复。测定分析3种植物生长延缓剂处理下板栗苗木营养枝、标准枝的生长动态及叶片内非结构性碳水化合物的含量。【结果】①多效唑、矮壮素和烯效唑均能显著降低板栗苗木枝条长度,增加枝条直径,对于标准枝喷施30 mg/L烯效唑效果最好,处理后90 d使得标准枝长度较对照减少24.13%,直径增加26.45%;②延缓剂促进苗木枝条粗壮、长度缩短,延缓板栗砧木生长,提高嫁接成活率并有利于嫁接后生长,100 mg/L多效唑对营养枝促壮效果最好,较对照增加36.63%,长度减少17.10%。③延缓剂处理后,板栗叶片可溶性糖含量升高,其中150 mg/L矮壮素处理板栗苗木叶片内可溶性糖含量始终处于最高水平,且显著高于对照,在处理后90 d达到最高(61.95 mg/g)。④不同延缓剂处理对叶片淀粉含量有不同的影响,处理后30 d,100 mg/L矮壮素处理叶片内淀粉含量始终处于最高水平,且显著高于对照,在处理后60 d和90 d,淀粉含量分别高达1.54、1.51 mg/g;⑤3种延缓剂均能提高板栗苗木内非结构性碳水化合物含量,200 mg/L矮壮素处理对苗木非结构性碳水化合物增加效果最好,该浓度处理后的板栗苗木,其叶片内非结构性碳水化合物总量始终处于最高水平,最高达62.60 mg/g,且显著高于对照。【结论】植物生长延缓剂使得板栗苗木枝条粗壮、长度缩短,抑制砧木生长,从而提高板栗嫁接成活率并有利于嫁接后生长,其中60 mg/L烯效唑对标准枝的处理效果最好,100 mg/L多效唑对营养枝促壮效果最好;对板栗苗木喷施延缓剂有利于其叶片的碳供应,200 mg/L矮壮素处理效果最好;在植物生长延缓剂实际应用于板栗苗木培育中,应根据生产目的合理选择不同种类延缓剂及适宜的质量浓度。

Different concentrations of paclobutrazol (PP333), chlormequat (CCC) and uniconazole (S3307) were sprayed to investigate the growth dynamics of branches and content of soluble sugar (SS), starch (ST) and non-structural carbohydrates (NSC) in leaves of chestnut (Castanea mollissima ) seedlings, in order to provide a theoretical basis for chemical regulation of chestnut. 【Method】A three-year-old chestnut ‘Yanshanzaofeng’ was used as a test material, and 15% paclobutrazol wettable powder, 50% chlormequat aqueous solution, and 5% uniconazole wettable powder formulation solution were selected as experimental solutions. During flower bud differentiation, we sprayed paclobutrazol (50, 100 and 150 mg/L), chlormequat (100, 150 and 200 mg/L) and uniconazole (30, 60 and 90 mg/L); the whole plant in each treatment was sprayed with clear water as a control (CK) on sunny and windless mornings until the leaves were covered with water droplets without dripping. To study the effects of three plant growth retardants on the growth dynamics of standard and vegetative branches of chestnut seedlings and the content of non-structural carbohydrates in leaves a single-factor completely random block design was used, with a single plant as a plot and five replicates for each treatment. 【Result】① Paclobutrazol, chlormequat and uniconazole significantly reduced the branch length of chestnut seedlings and increased the diameter of branches. The 30 mg/L uniconazole spray was the best for standard shoots. The length of standard shoot was reduced by 24.13% and diameter increased by 26.45% at 90 days after treatment. ② Retardants made the shoots thicker and shorter and could delay the growth of chestnut rootstock, improve the graft survival rate, and facilitate growth after grafting. The 100 mg/L paclobutrazol had the best effect in promoting nutrient shoot growth, making it more effective; the seedling branch increased by 36.63% and length decreased by 17.10%. ③ After spraying the seedlings with retardants, the soluble sugar content in chestnut leaves increased. Among them, the soluble sugar content in the leaves of chestnut seedlings treated with 150 mg/L chlormequat was always at the highest level and was significantly higher than that of the control. It reached the highest level (61.95 mg/g) after 90 days. ④ Different retardant treatments had different effects on the starch content of leaves. The starch content in leaves treated with 100 mg/L chlormequat at 30 days after treatment was always at the highest level and was significantly higher than that of the control. The contents were as high as 1.54 mg/g and 1.51 mg/g respectively. ⑤ All kinds of delaying agents could increase the content of non-structural carbohydrates in chestnut seedlings. After spraying the seedlings with retardants, the total amount of non-structural carbohydrates in the leaves of chestnut seedlings was always at the highest level and was significantly higher than that of the control.【Conclusion】Plant growth retardants made seedlings to grow thick, be shortened, and inhibited the growth of chestnut, improving the graft survival rate and facilitating the growth after grafting. Among the retardants, 30 mg/L uniconazole had the best treatment effect on standard shoots, while 100 mg/L paclobutrazol had the best effect in promoting the nutrient shoot growth. The application of retardants to chestnut seedlings was beneficial in the carbon supply of leaves. In this study, 200 mg/L chlormequat was the best treatment. Thus, in applying retardants for the cultivation of chestnut, different types and mass concentrations of retardants should be reasonably selected based on the purpose of production.