Limitation of Unloading in the Developing Grains Is a Possible Cause Responsible for Low Stem Non-structural Carbohydrate Translocation and Poor Grain Yield Formation in Rice through Verification of Recombinant Inbred Lines

Guohui Li; Junfeng Pan; Kehui Cui; Musong Yuan; Qiuqian Hu; Wencheng Wang; Pravat K Mohapatra; Lixiao Nie; Jianliang Huang; Shaobing Peng

doi:10.3389/fpls.2017.01369

Limitation of Unloading in the Developing Grains Is a Possible Cause Responsible for Low Stem Non-structural Carbohydrate Translocation and Poor Grain Yield Formation in Rice through Verification of Recombinant Inbred Lines

Front Plant Sci. 2017 Aug 8:8:1369. doi: 10.3389/fpls.2017.01369. eCollection 2017.

Authors

Guohui Li¹, Junfeng Pan¹, Kehui Cui^{1

2}, Musong Yuan¹, Qiuqian Hu¹, Wencheng Wang¹, Pravat K Mohapatra³, Lixiao Nie^{1

2}, Jianliang Huang^{1

2}, Shaobing Peng¹

Affiliations

¹ National Key Laboratory of Crop Genetic Improvement, MOA Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science and Technology, Huazhong Agricultural UniversityWuhan, China.
² Hubei Collaborative Innovation for Grain IndustryJinzhou, China.
³ School of Life Sciences, Sambalpur UniversitySambalpur, India.

Abstract

Remobilisation of non-structural carbohydrates (NSC) from leaves and stems and unloading into developing grains are essential for yield formation of rice. In present study, three recombinant inbred lines of rice, R91, R156 and R201 have been tested for source-flow-sink related attributes determining the nature of NSC accumulation and translocation at two nitrogen levels in the field. Compared to R91 and R156, R201 had lower grain filling percentage, harvest index, and grain yield. Meanwhile, R201 had significantly lower stem NSC translocation during grain filling stage. Grain filling percentage, harvest index, and grain yield showed the consistent trend with stem NSC translocation among the three lines. In comparison with R91 and R156, R201 had similarity in leaf area index, specific leaf weight, stem NSC concentration at heading, biomass, panicles m^-2, spikelets per panicle, remobilization capability of assimilation in stems, sink capacity, sink activity, number and cross sectional area of small vascular bundles, greater number and cross sectional area of large vascular bundles, and higher SPAD, suggesting that source, flow, and sink were not the limiting factors for low stem NSC translocation and grain filling percentage of R201. However, R201 had significant higher stem and rachis NSC concentrations at maturity, which implied that unloading in the developing grains might result in low NSC translocation in R201. The results indicate that stem NSC translocation could be beneficial for enhancement of grain yield potential, and poor unloading into caryopsis may be the possible cause of low stem NSC translocation, poor grain filling and yield formation in R201.

Keywords: grain yield formation; non-structural carbohydrates; rice (Oryza sativa L.); source-flow-sink attributes; translocation; unloading of assimilates.