夏玉米干物质累积与分配、叶片特性及籽粒败育对花粒期光照胁迫的响应

Response of Dry Matter Accumulation and Distribution,Leaf Characteristics and Kernel Abortion to Light Stress from Flowering to Maturity in Summer Maize

在大田条件下,在玉米花粒期设置透光率30%(S_(30))、透光率60%(S_(60))2个光照胁迫处理,以自然光照为对照(CK),研究了夏玉米干物质累积与分配、叶片特性及籽粒败育对花粒期光照胁迫的响应。结果表明:花粒期光照胁迫显著降低了夏玉米干物质累积,抑制了干物质向籽粒中的分配,向茎秆、叶片的分配比例增加。花粒期光照胁迫增加了比叶面积,随着光照胁迫强度的增加而上升,叶片变薄。在花粒期光照胁迫下LAI花后30 d降低,花后40 d下降显著,S_(30)的LAI略高于S_(60),但均低于CK。花粒期光照胁迫使穗位叶的Pn在不同时刻均显著低于CK,表现为S_(30)<S_(60)<CK,花后10 d的Pn均高于花后40 d,随着光照胁迫的增强,其Pn的衰减幅度升高。花粒期光照胁迫显著增加了叶绿素a、叶绿素b、叶绿素a+b含量。花粒期光照胁迫阻碍了籽粒的正常发育,败育籽粒增多,籽粒败育率、总败育率均显著高于CK,随着光照胁迫强度的增加而增加。花粒期光照胁迫显著降低了穗粒数、百粒重,秃尖显著变长,胁迫强度越大则其变化幅度也越大,致使玉米最终产量直接降低,2020年光照胁迫处理S_(30)、S_(60)的产量分别比CK降低了50.31%、25.34%;2021年光照胁迫处理S_(30)、S_(60)的产量分别比CK降低了52.94%、13.07%。

A field experiment was conducted to study the response of dry matter accumulation and distribution,leaf characteristics and kernel abortion to light stress from flowering to maturity in summer maize,and 2 light stress treatments from flowering to maturity were designed in the experiment,such as light transmittance 30%(S_(30))and 60%(S_(60)).Natural light was used as control.The results showed that light stress from flowering to maturity significantly decreased dry matter accumulation in summer maize,inhibited the distribution of dry matter to the grain,and increased the distribution ratio of stem and leaf.Light stress from flowering to maturity increased the specific leaf area,and increased with the increase of light stress intensity,while the leaves became thinner.Light stress from flowering to maturity decreased LAI at 30 days after flowering,and decreased significantly at 40 days after flowering.Treatment S_(30) was slightly higher than S_(60),but lower than CK.Light stress from flowering to maturity made ear leaf Pn significantly lower than that of natural light CK at different times,showing S_(30)<S_(60)<CK,The Pn of 10 days after flowering was higher than that of 40 days after flowering.With the increase of light stress,the attenuation range of Pn also increased.Light stress from flowering to maturity significantly increased the contents of chlorophyll a,chlorophyll b and chlorophyll a+b.Light stress from flowering to maturity impeded grain normal development,and abortive grain numbers increased.Grain abortive percentage and total abortive percentage were significantly higher than that of natural light,and increased with the increase of light stress intensity.Light stress from flowering to maturity significantly reduced grain number per ear and 100 grains weight,and bald tip became significantly longer.The greater the stress intensity,the greater the change range,resulting in direct reduction of corn final yield.The light stress treatment S_(30) and S_(60) decreased by 50.31%and 25.34%,respectively,compared with CK in 2020,and S_(30) and S_(60) decreased by 52.94%and 13.07%,respectively,compared with CK in 2021.