Circadian resonance, whereby a plant's endogenous rhythms are tuned to match environmental cues, has been repeatedly shown to be adaptive, although the underlying mechanisms remain elusive. Concomitantly, the adaptive value of nocturnal transpiration in C3 plants remains unknown because it occurs without carbon assimilation. These seemingly unrelated processes are interconnected because circadi...

of their natural distributions in southern Alberta, Canada. In this semi-arid area, poplars are obligate riparian species but they occupy several intergrading ecoregions. Populus deltoides Bartr. ex Marsh predominates in the warmest and driest eastern prairie ecoregions; P. balsamifera L. occupies the cooler and wetter western parkland and montane ecoregions; and P. angustifolia James and hybri...

Stomatal responsiveness to evaporative demand (air vapour pressure deficit (VPD)) ranges widely between species and cultivars, and mechanisms for stomatal control in response to VPD remain obscure. The interaction of irrigation and soil moisture with VPD on stomatal conductance is particularly difficult to predict, but nevertheless is critical to instantaneous transpiration and vulnerability to...

Container-grown black spruce (Picea mariana (Mill.) B.S.P.) seedlings were planted in trays containing a sand and peat mixture, and placed in a climate-controlled greenhouse. One group of seedlings was kept well-watered, and another group was subjected to three cycles of drought. Gas exchange analysis showed that mesophyll photosynthetic function was largely unimpaired by drought. In contrast, ...

Isoprene emission in relation to stomatal distribution and conductance was determined for the hypostomatous species, aspen and white oak, and the amphistomatous species, cottonwood. For aspen and oak, isoprene emission from the adaxial (nonstomatal) surface was <2% of that from the abaxial (stomatal) surface, even when stomata were closed by addition of abscisic acid (ABA). When treated with AB...

Root development is influenced by nutrient and water availabilities. Plants are able to adjust many attributes of their root in response to environmental signals including the size and shape of the primary root, lateral roots and root hairs. Here we investigated the response of roots to changes in the levels of leaf transpiration associated with altered stomatal frequency. We found that plants ...

mungbean (vigna radiata (l.) wilczek) or green gram as a dryland grain legume is exposed to varied timings and severity of drought stress, resulting in variability in photoassimilate production. in order to evaluate some physiological responses in one mungbean cultivar to timing and severity of drought stress, a 3-replicate rcbd (randomized complete block design) field experiment was carried ou...

abstract application of salicylic acid (sa) as a phytohormone has been increased due to its role in plant tolerance to environmental stresses such as drought. the main goal of this experiment was to evaluate the effects of sa on morphological and physiological characteristics of cucumber seedlings under drought stress. a factorial experiment based on completely randomized block design was condu...

The following three models were combined to predict simultaneously photosynthesis, stomatal conductance, transpiration and leaf temperature of a rose leaf: the biochemical model of photosynthesis of Farquhar, von Caemmerer and Berry (1980, Planta 149: 78-90), the stomatal conductance model of Ball, Woodrow and Berry (In: Biggens J, ed. Progress in photosynthesis research. The Netherlands: Marti...