Mahmood Aqib, Wang Wei, Ali Iftikhar, Zhen Fengxian, Osman Raheel, Liu Bing, Liu Leilei, Zhu Yan, Cao Weixing, Tang Liang
National Engineering and Technology Center for Information Agriculture, Nanjing Agricultural University, Nanjing 210095, China.
Key Laboratory for Crop System Analysis and Decision Making, Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Nanjing 210095, China.
Plants (Basel). 2021 May 20;10(5):1021. doi: 10.3390/plants10051021.
Extreme temperature events as a consequence of global climate change result in a significant decline in rice production. A two-year phytotron experiment was conducted using three temperature levels and two heating durations to compare the effects of heat stress at booting, flowering, and combined (booting + flowering) stages on the production of photosynthates and yield formation. The results showed that high temperature had a significant negative effect on mean net assimilation rate (MNAR), harvest index (HI), and grain yield per plant (YPP), and a significant positive effect under treatment T on mean leaf area index (MLAI) and duration of photosynthesis (DOP), and no significant effect on biomass per plant at maturity (BPP), except at the flowering stage. Negative linear relationships between heat degree days (HDD) and MNAR, HI, and YPP were observed. Conversely, HDD showed positive linear relationships with MLAI and DOP. In addition, BPP also showed a positive relationship with HDD, except at flowering, for both cultivars and Wuyunjing-24 at combined stages. The variation of YPP in both cultivars was mainly attributed to HI compared to BPP. However, for biomass, from the first day of high-temperature treatment to maturity (BPP), the main change was caused by MNAR followed by DOP and then MLAI. The projected alleviation effects of multiple heat stress at combined stages compared to single-stage heat stress would help to understand and evaluate rice yield formation and screening of heat-tolerant rice cultivars under current scenarios of high temperature during the rice-growing season.
全球气候变化导致的极端温度事件致使水稻产量显著下降。利用三个温度水平和两个加热持续时间进行了为期两年的人工气候箱试验，以比较孕穗期、开花期以及联合（孕穗期 + 开花期）阶段的热胁迫对光合产物生产和产量形成的影响。结果表明，高温对平均净同化率（MNAR）、收获指数（HI）和单株籽粒产量（YPP）有显著负面影响，在处理T下对平均叶面积指数（MLAI）和光合作用持续时间（DOP）有显著正面影响，除开花期外，对成熟时的单株生物量（BPP）无显著影响。观察到热度日（HDD）与MNAR、HI和YPP之间呈负线性关系。相反，HDD与MLAI和DOP呈正线性关系。此外，除开花期外，两个品种以及联合阶段的武运粳24的BPP与HDD也呈正相关。与BPP相比，两个品种YPP的变化主要归因于HI。然而，对于生物量，从高温处理的第一天到成熟（BPP），主要变化是由MNAR引起的，其次是DOP，然后是MLAI。与单阶段热胁迫相比，联合阶段多重热胁迫的预计缓解效应将有助于理解和评估水稻产量形成以及在当前水稻生长季节高温情况下筛选耐热水稻品种。
