生长前期光照强度对甘薯叶片光合生理和结薯的影响

Effect of light intensity on leaf photosynthetic physiology and root system of sweet potato in the early stage of growth

探明甘薯生长前期不同光照强度对叶片光合生理和结薯性的影响,为甘薯合理套作高位作物提供高产理论依据和实践对策。于2021年,以不同干率和叶型的甘薯品种S1(潮薯1号)、S2(广薯87)和S3(渝苏162)为主区,以L200[(200±50)μmol m^(-2)s^(-1)]、L500[(500±50)μmol m^(-2)s^(-1)]和L800[(800±50)μmol m^(-2)s^(-1)]不同光照强度为副区,开展双因素裂区试验,研究了叶片的光合特性、组织结构和植株结薯情况。结果表明,随着光照强度的减弱,甘薯叶片上表皮厚度、栅栏组织厚度、海绵组织厚度、叶片厚度、净光合速率(P_(n))、蒸腾速率(T_(r))、气孔导度(G_(s))、RUBP羧化酶活性、单株结薯数、单株薯重、块根干物质重逐渐降低,以高光照强度L800处理最优;而胞间CO_(2)浓度(C_(i))、叶绿素a含量、叶绿素b含量、类胡萝卜素含量、叶绿素a/b、块根干率,以低光照强度L200处理最优。通过因子分析综合评价,高干率S3品种在弱光环境下表现最好,低干率S1品种表现最差。甘薯叶片主要通过增加光合色素的含量与增加叶面积指数来提高对光能的捕获,协同叶片组织结构、光合生理及RUBP羧化酶活性的可塑性变化来适应弱光环境。

This study investigated the impact of different light intensities on leaf photosynthetic physiology and tuberization during the early growth stage of sweet potatoes.The findings contribute to theoretical and practical strategies for achieving high yields through relay intercropping of high-position crops with sweet potatoes.To explore the photosynthetic characteristics,tissue structure,and tuberization of sweet potato leaves,a two-factor split plot experiment was conducted in 2021.The main plot consisted of three sweet potato cultivars with varying root drying rates and leaf types:S1(Chaoshu 1),S2(Guangshu 87),S3(Yusu 162).The subplot included three light intensities:L200[(200±50)μmol m^(-2)s^(-1)],L500[(500±50)μmol m^(-2)s^(-1)],L800[(800±50)μmol m^(-2)s^(-1)].The results revealed that decreasing light intensity led to reductions in upper epidermis thickness,palisade tissue thickness,spongy tissue thickness,leaf thickness,net photosynthetic rate(P_(n)),transpiration rate(T_(r)),stomatal conductance(G_(s)),RUBP carboxylase activity,number of storage roots per plant,storage root weight per plant,and dry matter weight of storage roots.Among these parameters,the treatment with high light intensity(L800)exhibited the best performance.However,the intercellular CO_(2)concentration(C_(i)),chlorophyll a content,chlorophyll b content,carotenoid content,chlorophyll a/b ratio,and storage root drying rate were optimal under low light intensity(L200).Comprehensive evaluation through factor analysis revealed that the S3 variety with high root drying rate performed best under low light intensity,while the S1 variety with low root drying rate performed the worst.Sweet potato leaves primarily enhance light energy capture by increasing the content of photosynthetic pigments and leaf area index.They adapt to low light environments through plasticity in leaf anatomical structure,photosynthetic physiology,and RUBP carboxylase activity.