Hydraulic‐stomatal coordination in tree seedlings: tight correlation across environments and ontogeny in Acer pseudoplatanus

Abstract

1. Hydraulic conductance is recognized as a major determinant of gas exchange and productivity. However, whether this also applies to seedlings, a critically important stage for vegetation regeneration, has been largely unknown.2. We analyzed the hydraulic and stomatal conductance of leaves and shoots for 6-week-old Acer pseudoplatanus seedlings emerging in different lowland and treeline habitats and under glasshouse conditions, respectively, as well as on 9-, 15-and 18 week-old plants, and related findings to leaf and xylem anatomical traits.3. Treeline seedlings had higher leaf area-specific shoot hydraulic conductance (K shoot-L ), and stomatal conductance (g s ), associated with wider xylem conduits, lower leaf area and higher stomatal density than lowland and glasshouse-grown plants. Across the first 18 weeks of development, seedlings increased fourfold in absolute shoot hydraulic conductance (K shoot ) and declined by half in K shoot-L , with correlated shifts in xylem and leaf anatomy. Distal leaves had higher leaf hydraulic conductance (K leaf ) and g s compared to basal leaves. 4. Seedlings show strong variation across growth environments and ontogenetic shifts in hydraulic and anatomical parameters. Across growth sites, ontogenetic stages and leaf orders, g s was tightly correlated with K shoot-L and K leaf , balancing hydraulic supply with demand for the earliest stages of seedling establishment.

Comparative Apparent Hydraulic Conductance, Leaf Gas Exchange, and Water Resource Partitioning of Populus euphratica Trees and Saplings

“…In this study of both saplings and mature trees, leaf stomatal conductance had a strong positive correlation with K L (Figure 5a), suggesting that a decrease in leaf-specific apparent hydraulic conductance exercises a great influence on stomatal closure, reducing transpiration. This is in agreement with previous studies that documented the coordination of g s with plant hydraulic conductance [48,49]. Meanwhile, we found that the effect of K L on g s was different between saplings and mature trees via the slope rate of g s and K L (Figure 5a).…”

Influence of Juvenile Growth on Xylem Safety and Efficiency in Three Temperate Tree Species

“…However, growth performance was notably associated to a higher hydraulic efficiency in two of the three species, most likely through an increase in hydraulically-weighted vessel diameter (D h ), which was strongly and positively related to sapwood-specific hydraulic conductivity (K s ). In B. pendula and A. pseudoplatanus, two species with an isohydric water potential regulation strategy [45,58], and Kumar et al, unpublished, efficiency-related variables (e.g., D h and K s ) were associated with higher growth. This is consistent with earlier intra-and inter-specific studies reporting a close association of growth biomass increment to hydraulic efficiency rather than to other wood traits [14,34,37,59].…”

Kuraklık Stresi Altındaki İki Akçaağaç Türünün (Acer negundo ve Acer pseudoplatanus) Fidanlarının Gaz Değişim Parametrelerinin Karşılaştırılması

“…It is also a transformer species that significantly changes its ecosystem's conditions (Richardson et al, 2000). Conversely, A. pseudoplatanus is also an invasive species, but it is also a critical silvicultural and ecological role in European forests (Beikircher et al, 2021). Besides these, Acer species as urban plants provide ecosystem services that range from carbon sequestration and heavy metal accumulation to shading urban surroundings and improving urban life quality.…”