Sun Yan, Han Yang, Xu Zikai, Zhang Jinting, Shen Jianbo, Cheng Lingyun
College of Resources and Environmental Sciences, National Academy of Agriculture Green Development, Key Laboratory of Plant-Soil Interactions, Ministry of Education, State Key Laboratory of Nutrient Use and Management (SKL-NUM), China Agricultural University, Beijing, China.
Front Plant Sci. 2023 Jul 4;14:1223532. doi: 10.3389/fpls.2023.1223532. eCollection 2023.
Lower phosphorus (P) availability limits crop productivity in agroecosystems. The remobilization of P from the source to the sink organs plays an important role in enhancing the P-utilization efficiency of crops. During the grain filling stage, phosphorus flow to the developing grains, the primary sink, determines crop yield. However, the specific contributions of different organs to grain P throughout the post-silking period in maize remain unclear.
In our study, three maize inbred lines (CIMBL89, Ji846, and CML118) with contrasting P statuses were selected and grown in a field with high P (HP, 150 kg ha-1 P2O5) and low P (LP, 0 kg ha-1 P2O5) conditions.
The grain yield of CIMBL89 was 69% and 169% greater under HP supply, and 83% and 309% greater than those of Ji846 and CML118 under LP supply, respectively. The ear length, ear diameter, and kernel row number of CML118 were lower than those of CIMBL89 and Ji846 under HP conditions. Most of the P (87%) in the grains of CIMBL89 came from P uptake at the LP supply, while almost all P (95%) came from P remobilization in various organs at the HP supply after silking. In contrast, 91% of the P found in the grain of CML118 came from P remobilization under LP supply, while 76% came from P uptake under HP supply after silking.
In conclusion, our findings suggest that CIMBL89, with greater P acquisition efficiency, contributes to grain formation and production during the post-silking period under LP conditions. Additionally, CIMBL89 can fully remobilize P and avoid the extravagant absorption of P in P-sufficient soil, which sets it apart from Ji846 and CML118.
较低的磷（P）有效性限制了农业生态系统中作物的生产力。磷从源器官向库器官的再转运在提高作物磷利用效率方面发挥着重要作用。在灌浆期，流向发育中的籽粒（主要库）的磷决定作物产量。然而，玉米抽丝后不同器官对籽粒磷的具体贡献仍不清楚。
在我们的研究中，选择了三个磷状况不同的玉米自交系（CIMBL89、吉846和CML118），并在高磷（HP，150 kg ha-1 P2O5）和低磷（LP，0 kg ha-1 P2O5）条件的田间种植。
在高磷供应下，CIMBL89的籽粒产量分别比吉846和CML118高69%和169%；在低磷供应下，分别比吉846和CML118高83%和309%。在高磷条件下，CML118的穗长、穗直径和籽粒行数低于CIMBL89和吉846。CIMBL89籽粒中大部分磷（87%）来自低磷供应时的磷吸收，而在高磷供应下抽丝后，几乎所有磷（95%）来自各器官的磷再转运。相比之下，CML118籽粒中91%的磷来自低磷供应下的磷再转运，而76%来自高磷供应下抽丝后的磷吸收。
总之，我们的研究结果表明，CIMBL89具有更高的磷吸收效率，有助于在低磷条件下抽丝后籽粒的形成和生产。此外，CIMBL89能够充分再转运磷，避免在磷充足的土壤中过度吸收磷，这使其有别于吉846和CML118。
