不同密度杂草稻胁迫对栽培稻光合作用及生理特性的影响

为了探明杂草稻胁迫对栽培稻产量的影响及其生理原因,以杂草稻JS-Y1和栽培稻南粳44为材料,通过田间试验研究不同密度杂草稻(0,4,8,12,16株/m2)胁迫对栽培稻拔节期、抽穗期和灌浆中期光合性能、叶绿素荧光参数、透光率、膜脂过氧化和保护酶活性及产量的影响。结果表明:与对照相比,随着杂草稻发生密度的增加,杂草稻胁迫不同程度抑制了栽培稻不同生育期生理指标,影响栽培稻正常的生理功能,杂草稻的存在对栽培稻和杂草稻的共生群体的透光率造成了影响,在距地面20,50,80 cm和穗下10 cm,较对照分别降低54.03%~72.49%,39.68%~61.57%,48.98%~54.40%,38.07%~56.76%,达显著水平,叶片叶绿素含量、光合参数、PSⅡ的实际光化学效率(ФPSⅡ)和光化学淬灭系数(q P),以及膜脂过氧化酶活性,均随着栽培稻生育进程和杂草稻密度的增加而呈逐渐降低的趋势,在灌浆中期尤为明显;与对照(杂草稻发生密度为0)相比,杂草稻发生密度为4,8,12,16株/m2时,栽培稻产量分别下降了16.73%,43.01%,66.61%,83.24%,达显著差异。说明不同密度杂草稻胁迫时,影响了栽培稻群体的透光率,造成地上光合能力下降,栽培稻叶片细胞膜系统受到破坏是造成栽培稻产量降低的重要生理原因。

Effect of Weedy Rice with Different Densities Stress on the Photosynthesis and Physiological Characteristics of Cultivated Rice

In order to investigate the effect of weedy rice stress on grain yield of cultivated rice and its physio-logical mechanism,weedy rice JS-Y1 and rice cultivar Nanjing 44 were chosen as test materials in field experiment to study the effects of different densities(0,4,8,12,16 plant/m 2 ) of weedy rice stress on photosynthetic character-istics,chlorophyll fluorescence parameters,transmittance,lipids peroxidation and defensive enzyme activities and yield components of cultivated rice.The results showed that with the increase of weedy rice density,weedy rice sup-pressed the physiological stress indicators of cultivated rice in varying degrees at different growth stages comparing with the control,the transmittance in the height above the soil surface 20,50,80 cm and height below panicles 10 cm were declined by 54.03%-72.49%,39.68%-61.57%,48.98%-54.40% and 38.07%-56.76%,had sig-nificant difference compared with their controls,SPAD,photosynthetic parameters,ФPSⅡ,qP,lipids peroxidation and defensive enzyme activities were declined with the different growth stages and the increase of weedy rice density,es-pecially in the middle of filling stages.The production of cultivated rice with densities of 4,8,12,16 plant/m 2 weedy rice decreased by 16.73%,43.01%,66.61%,83.24%,had significant difference compared to control (no weedy rice planted).It was indicated that the main reasons causing the yield loss of cultivated rice was weedy rice with different densities stress on transmittance of cultivated rice population,caused the cell membrane system decom-posed and the declined photosynthetic capacity.