Leaf Senescence Research Articles

The clockwork of spring: bud dormancy timing as a driver of spring leaf-out in temperate deciduous trees

The initiation of spring leaf-out is a critical determinant of the growing season in trees, affecting primary production and species interactions in forest ecosystems. Variations in the timing of leaf-out among tree species are linked to their differential progression of bud dormancy. However, identifying reliable markers for bud dormancy has been challenging, leaving the connection between the timing of autumn leaf senescence, bud dormancy and spring leaf-out unclear. To test whether species initiating dormancy release earlier also exhibit earlier leaf senescence in autumn and earlier leaf-out in spring, we estimated the dates of peak dormancy depth (PDD), senescence timing and spring leaf-out across various species, locations and experimental conditions in Central Europe. PDD was defined as the date when the maximum thermal sum was required for leaf-out, whereas leaf senescence was assessed through the decrease in leaf greenness. Our findings reveal that PDD timing is a more accurate predictor of species-level differences in spring leaf-out dates than the timing of leaf senescence, the latter being a poor proxy for PDD. The observed temporal asynchrony between PDD and senescence was linked to dormancy induction showing species-specific sensitivity to temperature variations. Conversely, the timing of leaf senescence showed a consistent reaction to temperature changes across all species. These findings suggest that the physiological processes within buds and leaves during autumn are governed by distinct environmental cues, with the bud dormancy process serving as a more reliable predictor of spring phenological differences among forest tree species than does autumn leaf senescence.

Group C MAP kinases phosphorylate MBD10 to regulate ABA-induced leaf senescence in Arabidopsis.

Abscisic acid (ABA) is a phytohormone that promotes leaf senescence in response to environmental stress. We previously identified methyl CpG-binding domain 10 (MBD10) as a phosphoprotein that becomes differentially phosphorylated after ABA treatment in Arabidopsis. ABA-induced leaf senescence was delayed in mbd10 knockout plants but accelerated in MBD10-overexpressing plants, suggesting that MBD10 positively regulates ABA-induced leaf senescence. ABA-induced phosphorylation of MBD10 occurs in planta on Thr-89, and our results demonstrated that Thr-89 phosphorylation is essential for MBD10's function in leaf senescence. The in vivo phosphorylation of Thr-89 in MBD10 was significantly downregulated in a quadruple mutant of group C MAPKs (mpk1/2/7/14), and group C MAPKs directly phosphorylated MBD10 in vitro. Furthermore, mpk1/2/7/14 showed a similar phenotype as seen in mbd10 for ABA-induced leaf senescence, suggesting that group C MAPKs are the cognate kinases of MBD10 for Thr-89. Because group C MAPKs have been reported to function downstream of SnRK2s, our results indicate that group C MAPKs and MBD10 constitute a regulatory pathway for ABA-induced leaf senescence.

Anthocyanins act as a sugar-buffer and an alternative electron sink in response to starch depletion during leaf senescence: a case study on a typical anthocyanic tree species, Acer japonicum.

We hypothesized that anthocyanins act as a sugar-buffer and an alternative electron sink during leaf senescence to prevent sugar-mediated early senescence and photoinhibition. To elucidate the anthocyanin role, we monitored seasonal changes in photosynthetic traits, sugar, starch and N contents, pigment composition, and gene expression profiles in leaves exposed to substantially different light conditions within a canopy of an adult tree of fullmoon maple (Acer japonicum). Enhancement of starch amylolysis accompanied with cessation of starch synthesis occurred in the same manner independent of light conditions. Leaf sugar contents increased, but reached upper limits in the late stage of leaf senescence, even though leaf anthocyanins further increased after complete depletion of starch. Sun-exposed leaves maintained higher energy consumption via electron flow than shade-grown leaves during leaf N resorption. Thus, anthocyanins accumulated in sun-exposed leaves might have a regulative role as a sugar buffer, retarding leaf senescence, and an indirect photoprotective role as an alternative sink for electron consumption to compensate declines in other metabolic processes such as starch and protein synthesis. In this context, anthocyanins might be key substrates protecting both outer-canopy leaves (against photoinhibition) and inner-canopy leaves (via shading by outer-canopy leaves) from high light stress during N resorption.

Climate Adaptation in White Oak (Quercus alba, L.): A Forty-Year Study of Growth and Phenology

Climate change poses a significant threat to the resilience and sustainability of forest ecosystems. This study examines the performance of white oak (Quercus alba, L.) across a range of provenances in a common garden planting, focusing on the species’ response to climatic variables and the potential role of assisted migration in forest management. We evaluated the survival and growth rates of white oak provenances originating from various points along a latitudinal gradient over a period of 40 years. These provenances were planted in a common garden situated near the midpoint of this latitudinal gradient, where we also monitored their phenological traits, such as budburst and leaf senescence. The results revealed substantial variation in phenological responses and growth patterns among the provenances, with southern provenances demonstrating faster growth and later senescence relative to local sources, with limited impact on survival. In contrast, the northern provenances demonstrated slower growth, resulting in later-aged competition-induced mortality. The findings highlight the necessity of incorporating genetic diversity into white oak reforestation and conservation strategies, as the local provenance may no longer be the most suitable option for current and future conditions. We advocate for a nuanced approach to forest management that leverages genetic insights to optimize seed source selection for reforestation, fostering resilient forest landscapes in the face of ongoing climate shifts.

Historical tree phenology data reveal the seasonal rhythms of the Congo Basin rainforest.

Tropical forest phenology directly affects regional carbon cycles, but the relation between species-specific and whole-canopy phenology remains largely uncharacterized. We present a unique analysis of historical tropical tree phenology collected in the central Congo Basin, before large-scale impacts of human-induced climate change. Ground-based long-term (1937-1956) phenological observations of 140 tropical tree species are recovered, species-specific phenological patterns analyzed and related to historical meteorological records, and scaled to characterize stand-level canopy dynamics. High phenological variability within and across species and in climate-phenology relationships is observed. The onset of leaf phenophases in deciduous species was triggered by drought and light availability for a subset of species and showed a species-specific decoupling in time along a bi-modal seasonality. The majority of the species remain evergreen, although central African forests experience relatively low rainfall. Annually a maximum of 1.5% of the canopy is in leaf senescence or leaf turnover, with overall phenological variability dominated by a few deciduous species, while substantial variability is attributed to asynchronous events of large and/or abundant trees. Our results underscore the importance of accounting for constituent signals in canopy-wide scaling and the interpretation of remotely sensed phenology signals.

KAKU4 regulates leaf senescence through modulation of H3K27me3 deposition in the Arabidopsis genome

Lamins are the major components of the nuclear lamina, which regulate chromatin structure and gene expression. KAKU4 is a unique nuclear lamina component in the nuclear periphery, modulates nuclear shape and size in Arabidopsis. The knowledge about the regulatory role of KAKU4 in leaf development remains limited. Here we found that knockdown of KAKU4 resulted in an accelerated leaf senescence phenotype, with elevated levels of H2O2 and hormones, particularly SA, JA, and ABA. Our results demonstrated the importance of KAKU4 as a potential negative regulator in age-triggered leaf senescence in Arabidopsis. Furthermore, we conducted combination analyses of transcriptomic and epigenomic data for the kaku4 mutant and WT leaves. The knockdown of KAKU4 lowered H3K27me3 deposition in the up-regulated genes associated with hormone pathways, programmed cell death, and leaf senescence, including SARD1, SAG113/HAI1, PR2, and so forth. In addition, we found the functional crosstalks between KAKU4 and its associated proteins (CRWN1/4, PNET2, GBPL3, etc.) through comparing multiple transcriptome datasets. Overall, our results indicated that KAKU4 may inhibit the expression of a series of genes related to hormone signals and H2O2 metabolism by affecting the deposition of H3K27me3, thereby suppressing leaf senescence.

Complex Formation between the Transcription Factor WRKY53 and Antioxidative Enzymes Leads to Reciprocal Inhibition.

The transcription factor WRKY53 of the model plant Arabidopsis thaliana is an important regulator of leaf senescence. Its expression, activity and degradation are tightly controlled by various mechanisms and feedback loops. Hydrogen peroxide is one of the inducing agents for WRKY53 expression, and a long-lasting intracellular increase in H2O2 content accompanies the upregulation of WRKY53 at the onset of leaf senescence. We have identified different antioxidative enzymes, including catalases (CATs), superoxide dismutases (SODs) and ascorbate peroxidases (APXs), as protein interaction partners of WRKY53 in a WRKY53-pulldown experiment at different developmental stages. The interaction of WRKY53 with these enzymes was confirmed in vivo by bimolecular fluorescence complementation assays (BiFC) in Arabidopsis protoplasts and transiently transformed tobacco leaves. The interaction with WRKY53 inhibited the activity of the enzyme isoforms CAT2, CAT3, APX1, Cu/ZuSOD1 and FeSOD1 (and vice versa), while the function of WRKY53 as a transcription factor was also inhibited by these complex formations. Other WRKY factors like WRKY18 or WRKY25 had no or only mild inhibitory effects on the enzyme activities, indicating that WRKY53 has a central position in this crosstalk. Taken together, we identified a new additional and unexpected feedback regulation between H2O2, the antioxidative enzymes and the transcription factor WRKY53.

T-DNA insertion mutants of Arabidopsis DA1 orthologous genes displayed altered plant height and yield-related traits in rice (O. Sativa L.).

The Arabidopsis DA1 gene is a key player in the regulation of organ and seed development. To extend our understanding of its functional counterparts in rice, this study investigates the roles of orthologous genes, namely DA1, HDR3, HDR3.1, and the DA2 ortholog GW2, through the analysis of T-DNA insertion mutants. The aim of this research is to elucidate the impact of T-DNA insertions in DA1, HDR3, HDR3.1, and GW2 on agronomic traits in rice. By evaluating homozygous plants, we specifically focus on key parameters such as plant height, tiller number, days to heading, and grain size. T-DNA insertion locations were validated using PCR, and subsequent analyses were conducted on homozygous plants. Agronomic traits, including plant height, tiller number, days to heading, and grain size, were assessed. Additionally, leaf senescence assays were performed under dark incubation conditions to gauge the impact of T-DNA insertions on this physiological aspect. The study revealed distinctive phenotypic outcomes associated with T-DNA insertions in HDR3, HDR3.1, GW2, and DA1. Specifically, HDR3 and HDR3.1 mutants exhibited significantly reduced plant height and smaller grain size, while GW2 and DA1 mutants displayed a notable increase in both plant height and grain size compared to the wild type variety Dongjin. Leaf senescence assays further indicated delayed leaf senescence in hdr3.1 mutants, contrasting with slightly earlier leaf senescence observed in hdr3 mutants under dark incubation. The findings underscore the pivotal roles of DA1 orthologous genes in rice, shedding light on their significance in regulating plant growth and development. The observed phenotypic variations highlight the potential of these genes as targets for crop improvement strategies, offering insights that could contribute to the enhancement of agronomic traits in rice and potentially other crops.

Large Differences in Bud Burst and Senescence between Low- and High-Altitude European Beech Populations along an Altitudinal Transect in the South-Eastern Carpathians

Large Differences in Bud Burst and Senescence between Low- and High-Altitude European Beech Populations along an Altitudinal Transect in the South-Eastern Carpathians

Transcription factor NtNAC56 regulates jasmonic acid-induced leaf senescence in tobacco.

Leaf senescence is a vital aspect of plant physiology and stress responses and is induced by endogenous factors and environmental cues.. The plant-specific NAC (NAM, ATAF1/2, CUC2) transcription factor family influences growth, development, and stress responses in Arabidopsis (Arabidopsis thaliana) and other species. However, the roles of NACs in tobacco (Nicotiana tabacum) leaf senescence are still unclear. Here, we report that NtNAC56 regulates leaf senescence in tobacco. Transgenic plants overexpressing NtNAC56 (NtNAC56-OE) showed induction of senescence-related genes and exhibited early senescence and lower chlorophyll content compared to wild-type (WT) plants and the Ntnac56-19 mutant. In addition, root development and seed germination were inhibited in the NtNAC56-OE lines. Transmission electron microscopy observations accompanied by physiological and biochemical assays revealed that NtNAC56 overexpression triggers chloroplast degradation and reactive oxygen species accumulation in tobacco leaves. Transcriptome analysis demonstrated that NtNAC56 activates leaf senescence-related genes and jasmonic acid (JA) biosynthesis pathway genes. In addition, the JA content of NtNAC56-OE plants was higher than in WT plants, and JA treatment induced NtNAC56 expression. We performed DNA affinity purification sequencing to identify direct targets of NtNAC56, among which we focused on LIPOXYGENASE 5 (NtLOX5), a key gene in JA biosynthesis. A dual-luciferase reporter assay and a yeast one-hybrid assay confirmed that NtNAC56 directly binds to the TTTCTT motif in the NtLOX5 promoter. Our results reveal a mechanism whereby NtNAC56 regulates JA-induced leaf senescence in tobacco and provide a strategy for genetically manipulating leaf senescence and plant growth.

Deletion of the sugar importer gene OsSWEET1b accelerates sugar starvation-promoted leaf senescence in rice.

Leaf senescence is a combined response of plant cells stimulated by internal and external signals. Sugars acting as signaling molecules or energy metabolites can influence the progression of leaf senescence. Both sugar starvation and accumulation can promote leaf senescence with diverse mechanisms that are reported in different species. Sugars Will Eventually be Exported Transporters (SWEETs) are proposed to play essential roles in sugar transport, but whether they have roles in senescence and the corresponding mechanism are unclear. Here, we functionally characterized a sugar transporter, OsSWEET1b, which transports sugar and promotes senescence in rice (Oryza sativa L.). OsSWEET1b could import glucose and galactose when heterologously expressed in Xenopus oocytes and translocate glucose and galactose from the extracellular apoplast into intracellular cytosol in rice. Loss of function of OsSWEET1b decreased glucose and galactose accumulation in leaves. ossweet1b mutants showed accelerated leaf senescence under natural and dark-induced conditions. Exogenous application of glucose and galactose complemented the defect of OsSWEET1b deletion-promoted senescence. Moreover, the senescence-activated transcription factor OsWRKY53, acting as a transcriptional repressor, genetically functions upstream of OsSWEET1b to suppress its expression. OsWRKY53-overexpressing plants had attenuated sugar accumulation, exhibiting a similar phenotype as the ossweet1b mutants. Our findings demonstrate that OsWRKY53 downregulates OsSWEET1b to impair its influx transport activity, leading to compromised sugar accumulation in the cytosol of rice leaves where sugar starvation promotes leaf senescence.

Synergistic effects of planting density and nitrogen fertilization on chlorophyll degradation and leaf senescence after silking in maize

Regulating planting density and nitrogen (N) fertilization could delay chlorophyll (Chl) degradation and leaf senescence in maize cultivars. This study measured changes in ear leaf green area (GLAear), Chl content, the activities of Chl a-degrading enzymes after silking, and the post-silking dry matter accumulation and grain yield under multiple planting densities and N fertilization rates. The dynamic change of GLAear after silking fitted to the logistic model, and the GLAear duration and the GLAear at 42 d after silking were affected mainly by the duration of the initial senescence period (T1) which was a key factor of the leaf senescence. The average chlorophyllase (CLH) activity was 8.3 times higher than pheophytinase activity and contributed most to the Chl content, indicating that CLH is a key enzyme for degrading Chl a in maize. Increasing density increased the CLH activity and decreased the Chl content, T1, GLAear, and GLAear duration. Under high density, appropriate N application reduced CLH activity, increased Chl content, prolonged T1, alleviated high-density-induced leaf senescence, and increased post-silking dry matter accumulation and grain yield.

Leaf Senescence Database v5.0: A Comprehensive Repository for Facilitating Plant Senescence Research

Through an extensive literature survey, we have upgraded the Leaf Senescence Database (LSD v5.0; https://ngdc.cncb.ac.cn/lsd/), a curated repository of comprehensive senescence-associated genes (SAGs) and their corresponding mutants. Since its inception in 2010, LSD undergoes frequent updates to encompass the latest advances in leaf senescence research and its current version comprises a high-quality collection of 31,740 SAGs and 1,209 mutants from 148 species, which were manually searched based on robust experimental evidence and further categorized according to their functions in leaf senescence. Furthermore, LSD was greatly enriched with comprehensive annotations for the SAGs through meticulous curation using both manual and computational methods. In addition, it was equipped with user-friendly web interfaces that facilitate text queries, BLAST searches, and convenient download of SAG sequences for localized analysis. Users can effortlessly navigate the database to access a plethora of information, including literature references, mutants, phenotypes, multi-omics data, miRNA interactions, homologs in other plants, and cross-links to various databases. Taken together, the upgraded version of LSD stands as the most comprehensive and informative plant senescence-related database to date, incorporating the largest collection of SAGs and thus bearing great utility for a wide range of studies related to plant senescence.

Rice ONAC016 promotes leaf senescence through abscisic acid signaling pathway involving OsNAP

Senescence-induced NAC (senNAC) TFs play a crucial role in senescence during the final stage of leaf development. In this study, we identified a rice senNAC, ONAC016, which functions as a positive regulator of leaf senescence. The expression of ONAC016 increased rapidly in rice leaves during the progression of dark-induced and natural senescence. The onac016-1 knockout mutant showed a delayed leaf yellowing phenotype, whereas the overexpression of ONAC016 accelerated leaf senescence. Notably, ONAC016 expression was upregulated by abscisic acid (ABA), and thus detached leaves of the onac016-1 mutant remained green much longer under ABA treatment. Quantitative RT-PCR analysis showed that ONAC016 upregulates the genes associated with chlorophyll degradation, senescence, and ABA signaling. Yeast one-hybrid and dual-luciferase assays revealed that ONAC016 binds directly to the promoter regions of OsNAP, a key gene involved in chlorophyll degradation and ABA-induced senescence. Taken together, these results suggest that ONAC016 plays an important role in promoting leaf senescence through the ABA signaling pathway involving OsNAP.

Photosynthesis of rice leaves with a parallel venation is highly tolerant to vein severing.

Vein severing in plants caused by leaf damage is common in fields where crops are cultivated. It is hypothesized that leaves with complex reticulate venation can withstand hydraulic disturbances caused by vein severing, thereby preserving leaf carbon assimilation. However, limited research focuses on vein damage of leaves with parallel venation. We studied how vein-severing affected the photosynthetic traits of rice (Oryza sativa) leaves in seconds, minutes and days, under varying water-demand conditions and differing extents of water supply disruption. Rice leaves completely lost their photosynthetic capacity within 2.5 minutes after excision. Severing the midrib resulted in reduced light-saturated photosynthetic rate (A), stomatal conductance (gsw ) and transpiration rate (E) by 2.6, 6.8 and 5.9%, respectively, already after thirty minutes. We further investigated the photosynthetic trait responses to various extents of leaf width severing, while keeping the midrib functional. Surprisingly, A, gsw and E in the downstream area of the severed leaves largely remained stable, showing minimal variation across different leaf width severing ratios. These traits declined only slightly even under increased ambient light intensity and leaf-to-air vapor pressure deficit. This sustained photosynthesis post-severing is attributed to the efficient lateral water transport. Long-term leaf damage slightly but not significantly, impacted the downstream photosynthetic traits within five days post-severing. However, a more pronounced reduction in gas exchange during leaf senescence was observed nine days after severing. These findings suggested that rice leaves can tolerate hydraulic disturbances from vein severing and maintain functionality under various conditions, which is crucial for crop yield stability. However, long-term consequences require further investigation.

Decoding autumn phenology: Unraveling the link between observation methods and detected environmental cues.

Leaf coloring and fall mark the end of the growing season (EOS), playing essential roles in nutrient cycling, resource allocation, ecological interactions, and as climate change indicators. However, understanding future changes in autumn phenology is challenging due to the multitude of likely environmental cues and substantial variations in timing caused by different derivation methods. Yet, it remains unclear whether these two factors are independent or if methodological uncertainties influence the environmental cues determined. We derived start of growing season (SOS) and EOS at a mixed beech forest in Central Germany for the period 2000-2020 based on four different derivation methods using a unique long-term data set of in-situ data, canopy imagery, eddy covariance measurements, and satellite remote sensing data and determined their influence on a predictor analysis of leaf senescence. Both SOS and EOS exhibited substantial ranges in mean onset dates (39.5 and 28.6 days, respectively) across the different methods, although inter-annual variations and advancing SOS trends were similar across methods. Depending on the data, EOS trends were advanced or delayed, but inter-annual patterns correlated well (mean r = .46). Overall, warm, dry, and less photosynthetically productive growing seasons were more likely to be associated with a delayed EOS, while colder, wetter, and more photosynthetically productive vegetation periods resulted in an earlier EOS. In addition, contrary to recent results, no clear influence of pre-solstice vegetation activity on the timing of senescence was detected. However, most notable were the large differences in sign and strength of potential drivers both in the univariate and multivariate analyses when comparing derivation methodologies. The results suggest that an ensemble analysis of all available phenological data sources and derivation methods is needed for general statements on autumn phenology and its influencing variables and correct implementation of the senescence process in ecosystem models.

Tomato arabinosyltransferase prevents precocious senescence

Senescence, a crucial developmental process in the life cycle of plants, involves programmed destruction of cellular components of leaves. The onset of senescence is synchronized with other developmental processes for successful reproduction since senescence eventually leads to cell death. Arabinosyltransferase FASCIATED AND BRANCHED 2 (FAB2) is known to control meristem proliferation. Here, we show that FAB2 can inhibit premature leaf senescence in tomato plants. Both chemically mutagenized and CRISPR-generated fab2 mutants exhibited excessively accelerated senescence, which resulted in sterility. Transcriptome analysis revealed that FAB2 extended leaf longevity by suppressing transcription of genes highly expressed in mature leaves. Transcription of FAB2 was increased in younger leaves, potentially inhibiting premature leaf senescence. The precocious senescence of fab2 mutants was in contrast to fasciated inflorescence (fin) mutants, which carried mutations in a hydroxyproline O-arabinosyltransferase gene, leading to meristem overproliferation. Our observations indicate that complex genetic hierarchy in the cascade of tomato arabinosyltransferases could control different aspects of developmental processes such as stem cell proliferation and senescence.

Stable water isotopes reveal the onset of bud dormancy in temperate trees, whereas water content is a better proxy for dormancy release.

Earlier spring growth onset in temperate forests is a visible effect of global warming that alters global water and carbon cycling. Consequently, it becomes crucial to accurately predict the future spring phenological shifts in vegetation under different climate warming scenarios. However, current phenological models suffer from a lack of physiological insights of tree dormancy and are rarely experimentally validated. Here, we sampled twig cuttings of five deciduous tree species at two climatically different locations (270 and 750m a.s.l., ~ 2.3°C difference) throughout the winter of 2019-20. Twig budburst success, thermal time to budburst, bud water content and short-term 2H-labelled water uptake into buds were quantified to link bud dormancy status with vascular water transport efficacy, with the objective of establishing connections between the dormancy status of buds and their effectiveness in vascular water transport. We found large differences in the dormancy status between species throughout the entire investigation period, likely reflecting species-specific environmental requirements to initiate and release dormancy, whereas only small differences in the dormancy status were found between the two studied sites. We found strong 2H-labelled water uptake into buds during leaf senescence, followed by a sharp decrease, which we ascribed to the initiation of endodormancy. However, surprisingly, we did not find a progressive increase in 2H-labelled water uptake into buds as winter advanced. Nonetheless, all examined tree species exhibited a consistent relationship between bud water content and dormancy status. Our results suggest that short-term 2H-labelled water uptake may not be a robust indicator of dormancy release, yet it holds promise as a method for tracking the induction of dormancy in deciduous trees. By contrast, bud water content emerges as a cost-effective and more reliable indicator of dormancy release.

Divergence in Autumn Phenology Extracted From Different Satellite Proxies Reveals the Timetable of Leaf Senescence Over Deciduous Forests

AbstractRemote sensing detection of autumn phenology is challenging and highly uncertain, as exemplified by the observed divergence in autumn phenology extracted from different proxies. Here, we compared the autumn phenology derived from Solar‐Induced chlorophyll Fluorescence (SIF), Chlorophyll/Carotenoid Index (CCI), Enhanced Vegetation Index (EVI), and Normalized Difference Vegetation Index (NDVI) over deciduous forest sites. We observed a clear temporal sequence in the derived autumn phenology from various proxies: SIF < CCI < EVI < NDVI. Comparison with field measurements supported that SIF, EVI, and NDVI can successfully capture the attenuation of photosynthetic activity, leaf coloration, and leaf fall, respectively. The sequence among the autumn phenology derived from those proxies was also consistent with their responses to climate cues, where SIF had the highest partial correlation coefficient to solar radiation in autumn, followed by CCI, EVI, and NDVI, while NDVI was more correlated with temperature, followed by EVI, CCI, and SIF.

The complex stress of waterlogging and high temperature accelerated maize leaf senescence and decreased photosynthetic performance at different growth stages

AbstractThe greenhouse effect caused by global warming was becoming more and more obvious, resulting in increased frequency of high temperature and high humidity, which significantly affected maize productivity. However, it was poorly understood how the interactions of high temperature and high humidity affected leaf senescence, photosynthetic performance and yield of summer maize. Three stress treatments including (a) high temperature stress (T), (b) waterlogging stress (W) and (c) complex stress (T‐W) were set at the third leaf stage (V3), the sixth leaf stage (V6) and the tasselling stage (VT) in 2019–2020 to explore the influence mechanism of complex stress. Each stress treatment period lasted 6 days. Non‐stressed plants served as control. Yield, antioxidant enzyme activity, photosynthetic characteristics, and dry matter accumulation were determined. Our study found that the activity of antioxidant enzymes was significantly decreased, while malonyldialdehyde (MDA) accumulation was increased under each stress treatment. As a result, the photosynthetic characteristics were impaired, manifested in a significant decrease in net photosynthetic rate (Pn), enzyme activities of phosphoenolpyruvate carboxylase (PEPCase) and ribulose diphosphate carboxylase (RUBPCase). The decrease in photosynthetic intensity affected by each stress treatment led to a significant decrease in total dry matter accumulation and grain yield. The most significant effects of waterlogging and combined stresses on yield occurred at the V3 stage, followed by the V6 and VT stages. However, the most significant effects of high temperature occurred at the VT stage, followed by the V6 and V3 stages. Moreover, the compound stress exacerbated damage to leaf senescence and photosynthetic properties of summer maize compared to the single stress of high temperature or waterlogging.