植物学报2026，Vol.61Issue(1)：78-89,12.DOI:10.11983/CBB25016
抽穗期刈割改善密植甜高粱光合速率和生物量形成
Heading-stage Mowing Improves Photosynthetic Rate and Biomass Production in High-density Sweet Sorghum
摘要
Abstract
INTRODUCTION:Light intensity is an important environmental factor affecting plant photosynthesis.High-density plan-ting,an important crop cultivation practice for high yields,can reduce canopy light intensity,which decreases yield by reducing the rate of photosynthesis and the number of plant tillers.Given the large size of sweet sorghum plants which can naturally lead to dense canopy,we hypothesized that mowing might be able to increase photosynthetic rate and tillering,and population biomass,by improving the light environment within the canopy in high-density planted sweet sorghum. RATIONALE:Currently high-quality forage shortage is a serious problem in China.Sweet sorghum,a high quality forage crop ideal for silage,has attracted great attention due to its high biomass production and excellent palatability.This study aims to elucidate the patterns and physiological-ecological mechanisms by which mowing increases the population bio-mass of sweet sorghum,thus providing a theoretical basis for high-yield sweet sorghum cultivation. RESULTS:With increasing planting density(15 000,75 000,and 135 000 plant·hm-2),the main stem height of sweet sorghum increases,while stem diameter and leaf area decrease,accompanied by a reduction in the number of tillers.At the same time,the higher the planting density,the lower the canopy light intensity,the leaf photosynthetic performance and the fresh weight per plant,although the population-level fresh forage yield can increase significantly as the planting density increases up to 135 000 plant·hm-2.We found that heading-stage mowing largely increased the number of tillers(4.7,3.7,and 2.3 per plant,respectively)in all density treatments and reduced the tiller mortality by 35 days.In addition,heading-stage mowing significantly improved canopy light conditions,leaf photosynthetic efficiency and plant fresh weight in densely planted sweet sorghum,further increasing fresh grass yield.Our analysis showed that the average canopy light intensity and the net photosynthetic rate of functional leaves on the main stem were the main factors that influenced the actual tiller number and the main stem fresh weight,respectively. CONCLUSION:Our results demonstrated that high density planting is an important cultivation strategy for the high yields of sweet sorghum through improving the light environment within the dense canopy,thereby increasing the photosynthetic rate and the number of tillers per plant,and eventually increasing the population biomass.关键词
生物量/密植/光照强度/刈割/光合作用/甜高粱/分蘖Key words
biomass/high density planting/light intensity/mowing/photosynthesis/sweet sorghum/tillering引用本文复制引用
何梓齐,吴含玉,孙智超,胡婷婷,王英伟,张亚黎,姜闯道..抽穗期刈割改善密植甜高粱光合速率和生物量形成[J].植物学报,2026,61(1):78-89,12.基金项目
中国科学院先导专项(No.XDA26040103) （No.XDA26040103）
