Leaves of cotton (Gossypium hirsutum L.) were subjected to overpressures in a pressure chamber, and the exuded sap was collected and analyzed. The exudate contained low concentrations of solutes that were abundant in total leaf extracts, and photosynthetic rates and stomatal conductance were completely unaffected by a cycle of pressurization and rehydration. These criteria and others indicate t...

Ecosystems worldwide are facing increasingly severe and prolonged droughts during which hydraulic failure from drought-induced embolism can lead to organ or whole plant death. Understanding the determinants of xylem failure across species is especially critical in leaves, the engines of plant growth. If the vulnerability segmentation hypothesis holds within leaves, higher order veins that are m...

Cuticular wax deposition and composition affects drought tolerance and yield in plants. We examined the relationship between wax and dehydration stress by characterizing the leaf cuticular wax of tree tobacco (Nicotiana glauca L. Graham) grown under periodic dehydration stress. Total leaf cuticular wax load increased after each of three periods of dehydration stress using a CH2Cl2 extraction pr...

Leaf area expansion, dry weight, and water relations of Phaseolus vulgaris L. and P. acutifolius Gray were compared during a drying cycle in the greenhouse to understand the characteristics which contribute to the superior drought tolerance of P. acutifolius. Stomates of P. acutifolius closed at a much higher water potential than those of P. vulgaris, delaying dehydration of leaf tissue. P. acu...

Submergence and drought are major constraints to rice (Oryza sativa) production in rain-fed farmlands, both of which can occur sequentially during a single crop cycle. SUB1A, an ERF transcription factor found in limited rice accessions, dampens ethylene production and gibberellic acid responsiveness during submergence, economizing carbohydrate reserves and significantly prolonging endurance. He...

Submergence and drought are major constraints to rice (Oryza sativa) production in rain-fed farmlands, both of which can occur sequentially during a single crop cycle. SUB1A, an ERF transcription factor found in limited rice accessions, dampens ethylene production and gibberellic acid responsiveness during submergence, economizing carbohydrate reserves and significantly prolonging endurance. He...

Plants of Ramonda serbica were dehydrated to 3.6% relative water content (RWC) by withholding water for 3 weeks, afterwards the plants were rehydrated for 1 week to 93.8% RWC. Plasma membranes were isolated from leaves using a two-phase aqueous polymer partition system. Compared with well-hydrated (control) leaves, dehydrated leaves suffered a reduction of about 75% in their plasma membrane lip...

Extracellular freezing results in cellular dehydration caused by water efflux, which is likely regulated by aquaporins (AQPs). In a seasonal cold acclimation (CA) study of Rhododendron catawbiense, two AQP cDNAs, RcPIP2;1 and RcPIP2;2, were down-regulated as the leaf freezing tolerance (FT) increased from -7 to approximately -50 degrees C. We hypothesized this down-regulation to be an adaptive ...

Seed dehydration is the normal terminal event in the development of orthodox seeds and is physiologically related to the cessation of grain dry mass accumulation and crop grain yield. For a better understanding of grain dehydration, we evaluated the hypothesis that hydraulic conductance of the ear decreases during the latter stages of development and that this decrease results from disruption o...