Saline-water irrigation and plant growth regulator application on zucchini fruit yield and quality

ABSTRACT The objective of this study was to evaluate the effect of a plant growth regulator (PGR; Stimulate®) on the yield and quality of zucchini fruits from plants of the cultivar Caserta-Italiana grown under different salinity levels of the irrigation water (SLIW). A randomized block design was used, in a 2 × 6 factorial arrangement consisted of two SLIW (0.5 and 5.0 dS m-1) and six PGR application modes: imbibition of seeds for 8 h in distilled water (PGR-T1; Control); imbibition of seeds for 8 h in PGR at 10 mL L-1 (PGR-T2); imbibition of seeds for 8 h in PGR at 10 mL L-1 plus foliar application at 10 mL L-1 at the flowering stage (PGR-T3); imbibition of seeds for 8 h in PGR at 10 mL L-1 plus two foliar applications at the flowering stage and at 20 and 30 days after sowing (PGR-T4); foliar application at 10 mL L-1 at the flowering stage (PGR-T5); and two foliar applications at 10 mL L-1 at 20 and 30 days after sowing (PGR-T6). The SLIW affected differently the variables of the zucchini crops evaluated. The PGR application to plants under no salt stress (0.5 dS m-1) increased the solid soluble concentration and biomass accumulation of zucchini fruits. The PGR application as seed treatment and foliar application at the flowering stage increased the fruit yield of zucchini plants irrigated with saline water.摘要 本研究旨在评估植物生长调节剂（plant growth regulator, PGR；商品名Stimulate®）对不同灌溉水盐度水平（salinity levels of the irrigation water, SLIW）下种植的卡斯尔塔-意大利（Caserta-Italiana）品种西葫芦果实产量与品质的影响。试验采用随机区组设计，设置2×6析因处理组合，其中灌溉水盐度水平设2个梯度（0.5和5.0 dS·m⁻¹），植物生长调节剂施用方式设6种：1. 蒸馏水浸种8 h（PGR-T1，对照组）；2. 10 mL·L⁻¹的PGR溶液浸种8 h（PGR-T2）；3. 10 mL·L⁻¹的PGR溶液浸种8 h，且于开花期以10 mL·L⁻¹的PGR溶液进行叶面喷施（PGR-T3）；4. 10 mL·L⁻¹的PGR溶液浸种8 h，且分别在开花期、播种后20 d和30 d各进行1次叶面喷施（PGR-T4）；5. 于开花期以10 mL·L⁻¹的PGR溶液进行叶面喷施（PGR-T5）；6. 分别在播种后20 d和30 d以10 mL·L⁻¹的PGR溶液进行叶面喷施（PGR-T6）。灌溉水盐度水平对供试西葫芦的各项测定指标存在差异化影响。在无盐胁迫（0.5 dS·m⁻¹）条件下施用植物生长调节剂，可提升西葫芦果实的可溶性固形物浓度与生物量积累。对于采用盐水灌溉的西葫芦植株，以种子处理结合开花期叶面喷施的方式施用植物生长调节剂，可提高果实产量。