尿素对骠马胁迫紫苏幼苗的缓解效应

为探讨尿素对骠马胁迫紫苏幼苗的缓解效应，阐明适宜紫苏生长的最佳除草施肥条件。采用随机区组试验设计，在紫苏六叶期喷施不同浓度的尿素(0、1、2、4和8g/L)和6.9 %骠马水乳剂(0、1.33、2.66、5.32和 7.98 mL/L)，分析其对紫苏光合特性指标、荧光特性、杂草防效和籽粒产量的影响。结果表明，骠马显著降低紫苏叶片的叶绿素含量指数（CCI），净光合速率（Pn）和气孔导度（Gs）也均不同程度降低，胞间CO2浓度（Ci）升高，说明骠马显著抑制紫苏的光合特性，且表现出一定的剂量-效应关系；叶绿素荧光分析表明，除草剂显著降低了PSⅡ最大光化学效率（Fv/Fm）、PSⅡ潜在活性（Fv/Fo）、PSⅡ实际光化学效率（ФPSⅡ）及光化学荧光淬灭系数（qP），非光化学淬灭系数（NPQ）则呈一定的上升趋势。表明在除草剂骠马胁迫下紫苏叶片发生了光抑制，PSⅡ复合体受到损伤伴随着光合电子传递受阻；8 g/L的尿素处理效果相同；而1～4g/L浓度的尿素处理则效果相反。1～4 g/L的尿素和不同浓度的骠马先后处理，比单用骠马处理效果好，A组的P1N3处理可使籽粒产量比单独施用骠马增产11%，杂草防效提高11.35%，表明先施4 g/L的尿素再施1.33 mL/L 的骠马，能显著缓解骠马对紫苏的胁迫，提高其光合性能，并使其光系统Ⅱ维持较高的光化学效率，该施药模式具有平衡除草施肥技术，安全高产等特点，有较高的推广价值。

Puma stress alleviated by urea on Perilla frutescens (L.) Britt. seedlings

Abstract: Perilla with six leaves was exposed to combined treatment with urea (0, 1, 2, 4 and 8g/L) and puma super (0, 1.33, 2.66, 5.32 and 7.98mL/L) of different concentration to study the mitigative effect of urea on Perilla frutescens (L.) Britt. seedlings to Puma super stress and to find the best treatment. The effect of combinedd treatment on photosynthesis, chlorophyll fluorescence, weed control and seed yield of Perilla frutescens (L.) Britt. were studied by using the randomized block design experiment. Results showed that the chlorophyll content index reduced significantly, and photosynthetic rate (Pn), stomatal conductance(Gs) and transpiration rate (Tr) also reduced at various levels. The intercellular CO2 concentration (Ci) increased under Puma super treatments. It indicated that Puma super significantly inhibited the photosynthetic capacity. It also showed that Puma super significantly decreased maximum PSII photochemical efficiency, effective quantum yield of photochemical energy conversion in PSII, PSII potential activity and photochemical quenching of variable Chl fluorescence; and decreased non-photochemical Chl fluorescence quenching. It indicated that Puma super impaired PSII and blocked the electron transport in light reaction, treatment with urea of moderate concentration (1 to 4g/L) could antagonize the negative effect contributed by Puma super, while high concentration (8g/L) could aggravate this effect. The seed yield and weed control efficiency increased 11% and 11.35% respectively under leaf spray of 4g/L urea and followed by leaf spray of 1.33mL/L Puma super. These results indicated that the mitigative effect of urea on Perilla frutescens (L.) Britt. seedlings to Puma super stress increased effectively. The photosynthesis and PSII photochemical efficiency were improved after treated by 4g/L urea first and then by 1.33 mL/L Puma super. This combination of urea and clethodium could balance the fertilization and weeding, and further promote crop production.