Dynamics of dry matter accumulation in internodes indicates source and sink relations during grain-filling stage of japonica rice

A - Papers appearing in refereed journals

Xu, H., Wang, Z., Xiao, F., Yang, L., Li, G., Ding, Y., Paul, M. J., Li, W. and Liu, Z. 2020. Dynamics of dry matter accumulation in internodes indicates source and sink relations during grain-filling stage of japonica rice. Field Crops Research. (Article), p. 108009. https://doi.org/10.1016/j.fcr.2020.108009

AuthorsXu, H., Wang, Z., Xiao, F., Yang, L., Li, G., Ding, Y., Paul, M. J., Li, W. and Liu, Z.
Abstract

Storage of non-structural carbohydrates (NSC) in internode parenchyma before anthesis functions as a major carbon source for rice grain filling. In this study, two-year field and pot experiments with three japonica cultivars and two nitrogen (N) fertilization modes were performed, and dynamics of dry matter (DM) in internodes were quantified from 21 day before anthesis (DBA) to 60 day after anthesis (DAA; maturity). Results showed that in comparison to leaves and sheaths, DM in internodes varied dramatically, with a clear pattern of increasing at 21 DBA, peaking at 10 DAA, then dramatically dropping until 20 or 30 DAA, and finally refilling at maturity. The sharp reduction of dry matter in the internodes corresponded with the fastest rate of grain filling, indicating the importance of internode reserves for yield formation. On the other hand, the high rate of refilling in internodes at late stage implies the excess production of leaf photosynthetic assimilates. Similarly, starch content in internodes showed a pattern of decreasing at 20–30 DAA. To clarify the indicative meaning of internode reserves, we calculated their remobilization rate at 20 DAA and refilling rate at 60 DAA. Genotypic variations existed for the three cultivars, with a range of 15.17 %–36.37 % for remobilization rate and 54.36 %–104.33 % for refilling rates in 2018. Overall, N topdressing significantly increased the translocation of internode reserves for all three cultivars. Furthermore, our calculation showed that only about 10 % of the grain yield was formed during the second month of rice grain filling, indicating this period is less important for grain yield. Our findings help to clarify the significance of internode DM dynamics for rice management and should be beneficial to enhance our knowledge of source and sink relations, the fundamental component of crop yield formation.

KeywordsRice; Internode; Dry matter; Non-structural carbohydrates; Source and sink relation
Year of Publication2020
JournalField Crops Research
Journal citation(Article), p. 108009
Digital Object Identifier (DOI)https://doi.org/10.1016/j.fcr.2020.108009
Open accessPublished as non-open access
FunderBiotechnology and Biological Sciences Research Council
Funder project or codeDFW - Designing Future Wheat - Work package 1 (WP1) - Increased efficiency and sustainability
Output statusPublished
Publication dates
Online25 Nov 2020
Publication process dates
Accepted13 Nov 2020
PublisherElsevier Science Bv
ISSN0378-4290

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