National Key Laboratory for Plant Molecular Genetics, Chinese Academy of Science (CAS) Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, CAS, Building No. 1, Room 402, Fenglin Road 300, Shanghai, 200032, China.
University of Chinese Academy of Sciences, Beijing, 100049, China.
Sci Rep. 2020 Sep 9;10(1):14813. doi: 10.1038/s41598-020-71913-y.
Huanghuazhan (HHZ) and 9,311 are two elite rice cultivars in China. They have achieved high yield through quite different mechanisms. One of the major features that gives high yield capacity to 9,311 is its strong early vigor, i.e., faster establishment of its seedling as well as its better growth in its early stages. To understand the mechanistic basis of early vigor in 9,311, as compared to HHZ the cultivar, we have examined, under controlled environmental conditions, different morphological and physiological traits that may contribute to its early vigor. Our results show that the fresh weight of the seeds, at germination, not only determined the seedling biomass at 10 days after germination (DAG), but was also responsible for ~ 80% of variations in plant biomass between the two cultivars even up to 30 DAG. Furthermore, the 9,311 cultivar had a larger root system, which led to its higher nitrogen uptake capacity. Other noteworthy observations about 9,311 being a better cultivar than HHZ are: (i) Ten out of 15 genes involved in nitrogen metabolism were much more highly expressed in its roots; (ii) it had a higher water uptake rate, promoting better root-to-shoot nitrogen transfer; and (iii) consistent with the above, it had higher leaf photosynthetic rate and stomatal conductance. All of the above identified features explain, to a large extent, why the 9,311, as compared to HHZ, exhibits much more vigorous early growth.
黄花占（HHZ）和 9311 是中国的两个优质水稻品种。它们通过不同的机制实现了高产。9311 具有较强的早期活力，即更快地建立幼苗和更好地在早期生长，这是其高产的主要特征之一。为了了解 9311 与 HHZ 相比在早期活力方面的机制基础，我们在受控环境条件下检查了可能与其早期活力有关的不同形态和生理特征。我们的结果表明，种子在发芽时的鲜重不仅决定了发芽后 10 天（DAG）的幼苗生物量，而且还解释了两个品种之间植物生物量差异的约 80%，即使在 30 DAG 时也是如此。此外，9311 品种具有更大的根系，这导致其具有更高的氮吸收能力。关于 9311 比 HHZ 更好的品种的其他值得注意的观察结果是：（i）参与氮代谢的 15 个基因中有 10 个在其根部的表达要高得多；（ii）它具有更高的吸水速率，促进更好的根到梢的氮转移；（iii）与上述情况一致，它具有更高的叶片光合速率和气孔导度。所有上述确定的特征在很大程度上解释了为什么与 HHZ 相比，9311 表现出更强的早期生长活力。
