Xianke Yang

Reliable quantification of stomatal traits is essential for understanding plant gas exchange and its responses to environmental changes. However, grasses present methodological challenges due to their complex leaf surface topography and the distinctive dumbbell‐shaped stomata arranged in longitudinal rows. Here, we combined a literature‐based synthesis with comparative experiments to assess how measurement methods influence stomatal trait estimates and to characterize interspecific variation and environmental plasticity across Oryza species. Literature‐based synthesis revealed large cross‐study variations in reported stomatal density, with apparent differences of up to one order of magnitude among studies using SEM and impression‐based methods, although this variation may also reflect differences in genotypes, environments, developmental stages, and sampling protocols. Experimental comparisons confirmed consistent differences between SEM and imprint measurements, although the differences were smaller in magnitude. Across species, stomatal density, guard‐cell length, and guard‐cell width exhibited substantial diversity and conserved rankings across environments, while guard‐cell length showed greater environmental sensitivity. Moreover, method‐dependent differences significantly affected estimates of anatomical maximum stomatal conductance. Our results demonstrate that measurement methodology is an important source of uncertainty in stomatal trait estimation, even within the same leaf, and that Oryza species display broad interspecific morphological variations but comparatively constrained environmental responses. These findings highlight the need to standardize imaging protocols and to account for method‐dependent differences for accurate interpretation of relationships between stomatal morphology and functions in rice.

Summary: How plants cope with drought remains a major challenge in plant biology. Plants have evolved diverse drought resistance strategies, whether they operate synergistically or exhibit trade‐offs remains a critical knowledge gap. Here, we examined drought resistance strategies across 128 plant species, encompassing diverse plant phyla, original biomes, leaf types, and growth forms. Their leaf water retention capacity, rehydration capacity, and anatomical traits of leaves were measured. Our analyses revealed a significant negative correlation between leaf water retention capacity and rehydration capacity ( R ² = 0.55, P < 0.001), providing compelling evidence for an trade‐off between desiccation avoidance and desiccation tolerance at the leaf level. This trade‐off exhibits clear anatomical underpinnings in leaf structural traits including cell size, leaf thickness, vein density, and xylem proportion. We found significant variations in both capacities across plant phyla, original biomes, and leaf types, suggesting that vascular structure evolution and habitat adaptation may be primary drivers shaping drought resistance strategies. Notably, interspecific differences in leaf water retention capacity were mainly due to variations in water loss rate rather than water storage capacity. Our findings advance mechanistic understanding of drought resistance strategies across different plant types and contribute to improved predictions of vegetation responses to climate change.

The Huaihe River Basin (HRB) is situated in a transitional climate zone between northern and southern China, where droughts and floods have significantly impacted socioeconomic development. In this study, we employed a two‐dimensional bulk model to examine atmospheric water cycle processes and summer precipitation in the HRB. The region's precipitation primarily originates from advected moisture, mainly entering through southern and western boundaries. Although summer precipitation from advected moisture substantially exceeds that in winter, the precipitation recycling ratio is lower in summer (5.46%) than in winter (6.11%). Summer precipitation in the HRB shows a negative correlation with the precipitation recycling ratio, and its interannual variability is predominantly controlled by precipitation from advected moisture. Differences in water cycle processes between the years of summer drought and flood demonstrate that precipitation variations are largely driven by changes in the advected moisture. Composite analysis further reveals that precipitation in the HRB is influenced by anomalous moisture transport in the Indo‐Northwest Pacific. During drought and flood years, the HRB is affected by the cyclonic and anticyclonic moisture transport anomalies, respectively, and both moisture transport patterns are fundamentally controlled by large‐scale atmospheric circulation anomalies. This investigation of the atmospheric water cycle of HRB provides crucial insights for understanding the regional drought‐flood disaster mechanisms.

Climate‐related risks are shaped not only by changes in mean temperatures, but also by temperature variability, which raises the likelihood of extreme weather events with profound impacts on society and ecosystems. Previous studies have documented contrasting seasonal trend differences in summer and winter temperature variability across most land areas. However, spring—a phenologically sensitive season for agricultural systems—has received limited attention for its temperature variability. Focusing on the major rice‐growing regions in southern China, this study employs three indices—daily temperature standard deviation (STD), day‐to‐day temperature variability (DTD) and rapid cooling events (RCE)—to analyse the decadal trends and causes of spring temperature variability and assess its climate effects on rice yield anomalies. Our results reveal decadal trends in the spatial distribution of temperature variability, with increasing frequency and intensity in the Yangtze River Basin and Yunnan Province, and a decreasing trend across much of South China, closely following regional climatological patterns. Overall, the frequency and intensity of RCE trend exhibit a “strong gets weaker, weak gets stronger” pattern, likely linked to increased STD trends caused by spatial non‐uniformity of warming. Through a multiple regression statistical model employing dominance analysis, we find that climate factors, including both mean climate and climate variability, explained 19%–45% of the variance in provincial rice yield anomalies, with up to 13% of the explained variance attributable to spring climate factors related to temperature variability. This study underscores the critical role of spring temperature variability in climate resilience, highlights the urgent need to enhance the adaptability of agricultural systems to extreme climate events.

This study explores the relationship between summer‐developed ENSOs and tropical cyclone (TC) genesis over the western North Pacific (WNP) in distinguishing two types of summer ENSOs with distinct developing evolutions: so‐called ‘continuing ENSOs’ and ‘emerging ENSOs’. The summer equatorial Pacific sea surface temperature anomalies (SSTAs) during continuing ENSOs persist from the preceding winter, whereas emerging ENSOs feature a rapid decline in SSTAs from the preceding winter and newly develop from the following spring. The impact of summer ENSOs on WNP TC genesis is characterised by a shift in genesis location, as revealed in previous studies. The shift in genesis location is characterised by a zonal pattern with increased (decreased) TCs east (west) of 140° E in May to June (MJ) and a northwest–southeast dipole pattern with increased (decreased) TC genesis in the southeast (northwest) part of the WNP in July to September (JAS). The present study reveals that this impact of summer ENSOs is mainly contributed by emerging ENSOs, whereas the continuing type weakens ENSO's impact. During emerging ENSOs, more intense cyclonic anomalies over the central Pacific significantly intensify the monsoon trough east of 140° E, strengthening the impact of summer ENSOs on the location of TC genesis. The reduced vertical wind shear and enhanced absolute vorticity brought by the monsoon trough are important for the shift in TC genesis. The present study indicates that the classification of these two types of summer ENSOs with different temporal evolutions is a crucial factor in studying the impact of summer ENSOs on WNP TC activity.