植酶Q9对大田遮阴夏玉米产量和衰老特性的调控作用

黄淮海夏季太阳辐射量降低以及种植密度增加引起了夏玉米冠层光照不足,产量大幅降低。本试验选用夏玉米品种‘登海605'(DH605)为试验材料,设置3个遮阴处理:花粒期遮阴(S₁)、穗期遮阴(S₂)和全生育期遮阴(S₃),以大田自然光照为对照(CK),并选用化控试剂植酶Q9(原液稀释100倍)对遮阴处理和CK进行外源调控,即花粒期遮阴-植酶Q9(S₁Q)、穗期遮阴-植酶Q9(S₂Q)、全生育期遮阴-植酶Q9(S₃Q)及大田自然光照-植酶Q9(CKQ),化控处理以同时期喷施清水为对照,探讨植酶Q9对大田遮阴夏玉米衰老特性的调控作用。结果表明: 遮阴显著降低了夏玉米的叶面积指数(LAI)、功能叶片叶绿素相对含量值(SPAD值)和净光合速率,进而显著降低了夏玉米产量。同时,遮阴夏玉米穗位叶的超氧物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性显著降低,丙二醛(MDA)、游离脯氨酸含量显著增加,可溶性蛋白含量显著降低。喷施植酶Q9后,S₃Q和S₂Q的LAI、功能叶片SPAD值和净光合速率显著提高;S₃Q、S₂Q、S₁Q的MDA和游离脯氨酸含量显著降低,可溶性蛋白含量和POD活性显著提高,S₂Q、S₃Q各时期的SOD和CAT活性显著提高;S₃Q、S₂Q、S₁Q的产量分别较S₃、S₂、S₁平均提高19%、8%、7%,CKQ与CK间无显著差异。因此,喷施植酶Q9通过提高弱光胁迫下夏玉米的光合能力,延缓叶片的衰老,增加产量,可有效缓解弱光胁迫导致的减产危害。

Effects of phytase Q9 on the yield and senescence characteristics of summer maize shaded in the field

Light shortage in the canopy of summer maize resulted from the decrease of solar radiation and the increase of planting density in Huanghuaihai region could reduce maize yield. In order to explore the effects of phytase Q9 on leaf senescence characteristics of summer maize, three sha-ding treatments with summer maize hybrid ‘Denghai 605' (DH605) were conducted, including shading at flowering to maturity stage (S₁), shading at ear stage (S₂), and shading at whole growth stage (S₃) with natural lighting in the field as control (CK). Chemical control reagent phytase Q9 was used to regulate the shading treatments (the original solution was diluted by 100 times) and the CK exogenously, namely shading at flowering to maturity stage-phytase Q9 (S₁Q), shading at ear stage-phytase Q9 (S₂Q), and shading at whole growth stage-phytase Q9 (S₃Q), and natural lighting-phytase Q9 (CKQ), with spraying water at the same stage as the control. The results showed that leaf area index (LAI), soil-plant analysis development (SPAD) value and net photosynthetic rate of summer maize was significantly reduced by shading, which led to decreases of yield. The activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) in ear-leaf decreased. The content of malondialdehyde (MDA) and free proline increased, and that of soluble protein decreased. The spraying phytase Q9 significantly increased LAI, SPAD and net photosynthetic rate in S₃Q and S₂Q. MDA and free proline content in S₃Q, S₂Q, and S₁Q were significantly decreased, and soluble protein content and POD activity was significantly increased. SOD and CAT activities in S₂Q and S₃Q were significantly increased. The yield of S₃Q, S₂Q and S₁Q were 19%, 8% and 7% higher than that of S₃, S₂ and S₁ respectively. There was no significant difference between CKQ and CK. In conclusion, phytase Q9 could effectively alleviate the negative impact of low light on yield formation of summer maize, and increase grain yield by improving photosynthetic capacity of leaves and delaying leaf senescence.