This study investigates the functional significance of heterophylly in Ginkgo biloba, where leaves borne on short shoots are ontogenetically distinct from those on long shoots. Short shoots are compact, with minimal internodal elongation; their leaves are supplied with water through mature branches. Long shoots extend the canopy and have significant internodal elongation; their expanding leaves...

Replacing ultra-pure water solution with ion solution closer to the composition of natural xylem sap increases stem hydraulic conductance by up to 58%, likely due to changes in electroviscosity in the pit membrane pores. This effect has been proposed to contribute to the control of plant hydraulic and stomatal conductance and potentially to influence on carbon balance during dehydration. Howeve...

One of the most tantalizing unresolved questions in plant hydraulics is: where does water evaporate within the leaf? While several studies have explored experimental routes to answer this question (e.g. Sheriff & Meidner 1974; Farquhar & Raschke 1978), none have been able to provide a clear answer. In this issue of Plant, Cell & Environment, Tom Buckley has presented a new mathematical model in...

Improving water use efficiency (WUE) may prove a useful way to adapt crop species to drought. Since the recognition of the importance of mesophyll conductance to CO₂ movement from inside stomatal pores to the sites of photosynthetic carboxylation, there has been interest in how much intraspecific variation in mesophyll conductance (gm) exists, and how such variation may impact leaf WUE within C...

Young, visually symptomless leaves from potato (Solanum tuberosum) plants infected with Verticillium dahliae exhibited reduced carbon assimilation rate, stomatal conductance, and intercellular CO(2), but no increase in dark respiration, no change in the relationship between carbon assimilation rate versus intercellular CO(2), and no change in light use efficiency when intercellular CO(2) was he...

Limited mesophyll diffusion conductance to CO(2) (g(m)) can significantly constrain plant photosynthesis, but the extent of g(m)-limitation is still imperfectly known. As g(m) scales positively with foliage photosynthetic capacity (A), the CO(2) drawdown from substomatal cavities (C(i)) to chloroplasts (C(C), C(i)-C(C)=A/g(m)) rather than g(m) alone characterizes the mesophyll diffusion limitat...

this experiment was conducted to study the effect of plastic mulch on the growth and some physiological characteristics of two strawberry cultivars (paros and queen elisa) under drought stress. a factorial experiment was performed based on randomized complete block design with four treatments, including mulch, without mulch, normal irrigation (control) and deficit irrigation (-10 bar) with thre...

There are two optima for maximizing hydraulic conductance per vasculature volume in plants. Murray's law (ML) predicts the optimal conduit taper for a fixed change in conduit number across branch ranks. The opposite, the Yarrum optimum (YO), predicts the optimal change in conduit number for a fixed taper. We derived the solution for YO and then evaluated compliance with both optima within the x...

As trees grow taller, decreased xylem path conductance imposes a major constraint on plant water and carbon balance, and is thus a key factor underlying forest productivity decline with age. The responses of stomatal conductance, leaf area: sapwood area ratio ( A L : A S ) and soil–leaf water potential gradient ( DY S–L ) to height growth were investigated in maritime pine trees. Extensive meas...

Salinity significantly limits leaf photosynthesis but the factors causing the limitation in salt-stressed leaves remain unclear. In the present work, photosynthetic and biochemical traits were investigated in four rice genotypes under two NaCl concentration (0 and 150 mM) to assess the stomatal, mesophyll and biochemical contributions to reduced photosynthetic rate (A) in salt-stressed leaves. ...