Texas A&M AgriLife Research and Extension Center, 6500 Amarillo Blvd W, Amarillo, TX, 79106, USA.
Department of Agricultural Science, West Texas A&M University, Canyon, TX, 79106-0001, USA.
Planta. 2021 Sep 3;254(4):63. doi: 10.1007/s00425-021-03712-2.
The expression of stay-green (SG) characteristic in sorghum under water stress was related to N supply. SG genotype performed better than a non-stay-green (NSG) genotype at medium and high N levels. The differences in physiological parameters between SG and NSG genotypes were not significant at low N level and severe water stress. Grain sorghum [Sorghum bicolor (L.) Moench] with stay-green (SG) trait has the potential to produce more biomass and use soil water and nitrogen (N) more efficiently under post-flowering water stress. Previous studies were mostly conducted without N deficiency and more information is needed for interactions among soil N availability, SG genotype, and post-flowering water stress. In this study, the differences in leaf growth and senescence, shoot and root biomass, evapotranspiration (ET), water use efficiency (WUE), leaf photosynthetic responses, and nitrogen use efficiency (NUE) between a SG genotype (BTx642) and a non-stay-green (NSG) genotype (Tx7000) were examined. The two genotypes were grown at three N levels (Low, LN; Medium, MN; High, HN) and under three post-flowering water regimes (No water deficit, ND; Moderate water deficit, MD; Severe water deficit, SD). The genotypic difference was generally significant while it frequently interacted with N levels and water regimes. At medium and high N levels, SG genotype consistently had greater green leaf area, slower senescence rate, more shoot biomass and root biomass, and greater WUE and NUE than the NSG genotype under post-flowering drought. However, differences in several variables (e.g., leaf senescence, ET, WUE and NUE) between genotypes were not significant under SD at LN. At HN and MN, photosynthetic function of SG genotype was better maintained under drought. At LN, SG genotype maintained greater green leaf area but had lower photosynthetic activity than the NSG genotype. Nonetheless, adequate N supply is important for SG genotype under drought and greater root biomass may contribute to greater NUE in SG genotype.
在水分胁迫下，高粱中保持绿叶（SG）特性的表达与氮供应有关。在中高氮水平下，SG 基因型的表现优于非保持绿叶（NSG）基因型。在低氮水平和严重水分胁迫下，SG 和 NSG 基因型之间的生理参数差异不显著。具有保持绿叶（SG）特性的粮用高粱 [高粱（L.）莫恩奇]在花后水分胁迫下具有产生更多生物量和更有效地利用土壤水和氮（N）的潜力。以前的研究大多是在没有氮缺乏的情况下进行的，因此需要更多关于土壤氮供应、SG 基因型和花后水分胁迫之间相互作用的信息。在这项研究中，研究了 SG 基因型（BTx642）和非保持绿叶（NSG）基因型（Tx7000）之间叶片生长和衰老、地上部和根生物量、蒸散（ET）、水分利用效率（WUE）、叶片光合响应和氮利用效率（NUE）的差异。在三种氮水平（低氮、LN；中氮、MN；高氮、HN）和三种花后水分处理（无水分亏缺、ND；中度水分亏缺、MD；严重水分亏缺、SD）下种植了这两种基因型。基因型差异通常是显著的，但它经常与氮水平和水分处理相互作用。在中高氮水平下，SG 基因型在花后干旱下始终具有更大的绿叶面积、更慢的衰老率、更多的地上部和根生物量、更高的 WUE 和 NUE，而 NSG 基因型则没有。然而，在 LN 下，SD 下，基因型之间的几个变量（例如叶片衰老、ET、WUE 和 NUE）的差异不显著。在 HN 和 MN 下，SG 基因型的光合功能在干旱下得到更好的维持。在 LN 下，SG 基因型保持了更大的绿叶面积，但光合活性低于 NSG 基因型。尽管如此，氮的充足供应对干旱下的 SG 基因型很重要，更大的根生物量可能有助于 SG 基因型更高的 NUE。
