温室盆栽1年紫花苜蓿产量和光合速率的变化规律

采用盆栽方法,将8个紫花苜蓿(Medicago sativa)品种播种在智能温室内,保持一致的适宜温度、光照和水肥环境,探讨其各茬产量、叶绿素和光合速率的变化规律.为验证第1年得到的试验结果,第2年另选4个紫花苜蓿品种在相同生长条件下重复本试验.结果表明:在适宜的光、温、水肥条件下,紫花苜蓿播种后第1～3茬产量逐渐升高,之后基本保持稳定.第1～6茬初花期收获时株高、叶绿素含量和净光合速率变化不大,大部分茬次间差异不显著.相关分析表明,株高、单叶重与产量成正相关.综合分析认为,紫花苜蓿各茬产量主要受环境的影响,温室栽培下生长至一定时间时,产量可保持稳定.

Photosynthetic Characterization of Yield Variations of Alfalfa under Greenhouse Conditions for First Year

Alfalfa (Medicago sativa) is usually harvested 3～6 times annually. The biomass yields of first cut in the spring are generally the highest in practice. The yields are then declining in the following cuts. This seasonal reduction in alfalfa biomass yields could be associated with prevailing changes in environmental factors such as rainfall and heat stress or due to biological characteristics of alfalfa itself. In order to answer this question even clearly, 8 alfalfa varieties were grown under the controlled greenhouse conditions with suitable temperature, light, water and nutrient supply to determine the driving force of biomass yield variations of alfalfa genotypes. Another 4 alfalfa varieties were chosen to repeat the experiment in the second year. The results showed that the biomass yields of the alfalfa plants increased from first cut to third cut. The yields after third cut were stabilized. The biomass yields of alfalfa remained similar or even increased from the first to last cut without high temperature, water deficit and nutrient limitations. These data implied that dry matter yield was positively correlated with plant height and leaf weight.