Lodging is an important factor that restricts the yield of rapeseed and the mechanical harvesting. To explore agricultural practise and mechanisms that can synergistically improve the rapeseed yield and lodging resistance, a conventional plant type HZ 62 was selected in 2016–2017, and HZ 62 and an erect-leaf type 1,301 were grown in 2017–2018. The planting density was set as main plots at 15 × 10⁴ plants ha¹ (D1), 30 × 10⁴ plants ha^-1 (D2) and 45 × 10⁴ plants ha⁻¹ (D3), with the row spacing as sub-plots of 15 cm (R15), 25 cm (R25) and 35 cm (R35). The results showed that with increased density and narrowed row spacing, the radiation utilisation efficiency (RUE) of the population and seed yield were greatly increased. Compared with that at D1R25, the yield of HZ 62 at D3R15 was increased by 19.00% and 22.53%, respectively, in 2016–2017 and 2017–2018, whereas the yield of 1,301 rose by 31.98%. The influence of the RUE on the seed yield reached the peak at flowering stage. With increased planting density and narrowed row spacing, the lodging index of HZ 62 declined. The lodging index of 1,301 was increased with higher density and declined with narrowed row spacing. Compared with D1R25, the averaged lodging index across different parts of HZ 62 at D3R15 declined by 15.03% and 10.80%, respectively, in 2016–2017 and 2017–2018, and that of 1,301 was increased by 25.47%. Compared with D1R25, the stem proteomics during the flowering stage showed the expression of photosynthesis-related proteins (A0A078FHG9, A0A078JZM9 and A0A078JQI2) up-regulated, that consistent with Rubisco, SPS and FBPase activities; proteins related to phenylpropanes metabolism, A0A078IWR4 of HZ 62 and A0A078JWZ9 of 1,301 increased that consistent with POD activity, which resulted in more sucrose, starch and lignin in the stem at D3R15. Moreover, the protein related to cellulose synthesis (A0A078I4D9), the activity of β-1,3-glucanase and content of cellulose in the stem were up-regulated in HZ 62 but down-regulated in 1,301, contrary to the variation in the stem lodging index. The cellulose synthesis differed between the varieties in different treatment combinations of planting density and row spacing. This was the key process by which planting density and row spacing influence the lodging of rapeseed varieties with varied plant architecture.

中文翻译：

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不同种植密度和行距下油菜茎的生理和蛋白质组学特性影响种子产量和抗倒伏性

倒伏是制约油菜产量和机械收获的重要因素。为了探索协同提高油菜籽产量和抗倒伏性的农业实践和机制，2016-2017年选择了常规株型HZ 62，2017-2018年种植了HZ 62和直立叶型1,301。种植密度设置为主地块，15 × 10 ⁴株 ha ¹ (D1)、30 × 10 ⁴株 ha ^-1 (D2) 和 45 × 10 ⁴株 ha ^-1(D3)，行距为 15 cm (R15)、25 cm (R25) 和 35 cm (R35) 的子地块。结果表明，随着密度的增加和行距的缩小，种群的辐射利用效率（RUE）和种子产量大大提高。与D1R25相比，D3R15的HZ 62在2016-2017年和2017-2018年分别增加了19.00%和22.53%，而1,301的产量增加了31.98%。RUE对种子产量的影响在开花期达到高峰。随着种植密度的增加和行距的缩小，HZ 62的倒伏指数下降。1,301 的倒伏指数随着密度的增加而增加，随着行距的缩小而下降。与D1R25相比，D3R15HZ 62不同地区的平均住宿指数分别下降了15.03%和10.80%，2016-2017年和2017-2018年，1301个增长25.47%。与D1R25相比，开花期茎蛋白质组学显示光合作用相关蛋白（A0A078FHG9、A0A078JZM9和A0A078JQI2）表达上调，与Rubisco、SPS和FBPase活性一致；与苯丙烷代谢相关的蛋白质，HZ 62 的 A0A078IWR4 和 1,301 的 A0A078JWZ9 增加，这与 POD 活性一致，导致 D3R15 茎中更多的蔗糖、淀粉和木质素。此外，与纤维素合成相关的蛋白质（A0A078I4D9）、β-1,3-葡聚糖酶活性和茎中纤维素含量在HZ 62中上调而在1,301中下调，与茎中的变异相反住宿指数。不同种植密度和行距处理组合的品种间纤维素合成量不同。这是种植密度和行距影响具有不同植物结构的油菜品种倒伏的关键过程。