Arabidopsis vascular complexity and connectivity controls PIN-FORMED1 dynamics and lateral vein patterning during embryogenesis

Arabidopsis VASCULATURE COMPLEXITY AND CONNECTIVITY (VCC) is a plant-specific transmembrane protein that controls the development of veins in cotyledons. Here we show that the expression and localization of the auxin efflux carrier PIN-FORMED1 (PIN1) is altered in vcc developing cotyledons and that overexpression of PIN1-GFP partially rescues vascular defects of vcc in a dosage-dependent manner. Genetic analyses suggest that VCC and PINOID (PID), a kinase that regulates PIN1 polarity, are both required for PIN1-mediated control of vasculature development. VCC expression is upregulated by auxin, likely as part of a positive feedback loop for the progression of vascular development. VCC and PIN1 localized to the plasma membrane in pre-procambial cells but are actively redirected to vacuoles in procambial cells for degradation. In the vcc mutant, PIN1 failed to properly polarize in pre-procambial cells during the formation of basal strands and instead, it is prematurely degraded in vacuoles. VCC plays a role in localization and stability of PIN1, which is critical for the transition of pre-procambial into procambial cells involved in the formation of basal lateral strands in embryonic cotyledons.

Characterization of α2-Adrenergic Receptors Mediated Vasoconstriction in ex vivo model

Introductionrat tail serves as a thermoregulatory organ by dilating or constricting tail blood vessels and rat tail lateral veins play a role in cutaneous circulation. However, this cutaneous vessel has never been examined and evaluated as a potential candidate ex vivo model to study peripheral vascular diseases. This study aims to investigate vascular tone mediated through α2-adenergic receptor on rat tail vein under different temperatures.MethodsVasoconstriction stimulated by α2-adrenergic receptor selective agonists UK14304, guanabenz was thoroughly examined in isolated rat tail lateral vein. Susceptibility of cutaneous vessel to temperature changes was investigated under 37 °C and 28 °C. Differentiated vascular reactivity exhibited at different temperature was further explored with different α2-adrenergic receptor selective agonists and validated with antagonism by α1-adrenergic receptor and α2-adrenergic receptor selective antagonist prazosin and RX821002, respectively.ResultsVascular tone of freshly isolated vein remained same compared with that of stored in pre-gassed physiologic buffer at 4 °C overnight. Presence of endothelium and repeated administration of UK14304 did not alter contractile property. Vessels away from torso (distal) showed significantly different contractile character compared with portion close to torso (proximal) at 28 °C but kept uniform at 37 °C. Enhanced vasoconstriction along with increased potency of α2-adrenergic receptor agonists UK14304 and guanabenz was consistently present at 28 °C, independent of temperature change orders. Potentiated vasoconstriction present at 28 °C was later proved via α2-adrenergic receptor alone.DiscussionHarvest and preparation of rat tail lateral vein was described in details. Contractile property of venous preparations stimulated by α2-adrenergic receptor selective agonists was first time examined. Differentiated vasoconstriction at moderate cooling temperature was described and confirmed to through α2-adrenergic receptor activation. Rat tail lateral vein is found valuable for studies of cutaneous circulation altered by temperature changes.

Adaptation of cucumber seedlings to low temperature stress by reducing nitrate to ammonium during it’s transportation

Background Low temperature severely depresses the uptake, translocation from the root to the shoot, and metabolism of nitrate and ammonium in thermophilic plants such as cucumber (Cucumis sativus). Plant growth is inhibited accordingly. However, the availability of information on the effects of low temperature on nitrogen transport remains limited. Results Using non-invasive micro-test technology, the net nitrate (NO3−) and ammonium (NH4+) fluxes in the root hair zone and vascular bundles of the primary root, stem, petiole, midrib, lateral vein, and shoot tip of cucumber seedlings under normal temperature (NT; 26 °C) and low temperature (LT; 8 °C) treatment were analyzed. Under LT treatment, the net NO3− flux rate in the root hair zone and vascular bundles of cucumber seedlings decreased, whereas the net NH4+ flux rate in vascular bundles of the midrib, lateral vein, and shoot tip increased. Accordingly, the relative expression of CsNRT1.4a in the petiole and midrib was down-regulated, whereas the expression of CsAMT1.2a–1.2c in the midrib was up-regulated. The results of 15N isotope tracing showed that NO3−-N and NH4+-N uptake of the seedlings under LT treatment decreased significantly compared with that under NT treatment, and the concentration and proportion of both NO3−-N and NH4+-N distributed in the shoot decreased. Under LT treatment, the actual nitrate reductase activity (NRAact) in the root did not change significantly, whereas NRAact in the stem and petiole increased by 113.2 and 96.2%, respectively. Conclusions The higher net NH4+ flux rate in leaves and young tissues may reflect the higher NRAact in the stem and petiole, which may result in a higher proportion of NO3− being reduced to NH4+ during the upward transportation of NO3−. The results contribute to an improved understanding of the mechanism of changes in nitrate transportation in plants in response to low-temperature stress.

Hoya gaoligongensis (Apocynaceae, Asclepiadoideae), a new species from Yunnan, SW China

We describe and illustrate Hoya gaoligongensis M.X. Zhao & Y.H. Tan (Apocynaceae, Asclepiadoideae), a new species native to mid-elevation moist evergreen broadleaved forests of Longling, Yunnan, SW China. We further compare the primary diagnostic morphological characters of H. gaoligongensis to its close relatives, H. yuennanensis Hand.-Mazz. and H. globulosa Hook.f. Compared with these two species, H. gaoligongensis has narrower long-oblanceolate leaves, much smaller lateral vein branch angles, and inconspicuous lateral veins. Although the corolla is similar in all three species, the relative positions of outer and inner corona lobe processes serve as a key character distinguishing these species. A side view of the corona of H. gaoligongensis shows that the outer lobe process is only slightly higher than the inner process, while the corresponding parts of H. yuennanensis are much higher, and those of H. globulosa are at almost equal heights. In addition, the glabrescent leaves and stems of both H. gaoligongensis and H. yuennanensis separate these taxa from H. globulosa.

A comparative study of lateral and palmar venous anastomosis in Ishikawa zone Ⅱ fingertip replantation

Purpose: Venous anastomosis is the key procedure for Ishikawa zone Ⅱ fingertip replantation. Both palmar and lateral veins provide efficient venous drainage. This study compared the clinical effects between these venous anastomoses for fingertip replantation. Methods: In 2016–2018, 61 patients underwent Ishikawa zone Ⅱ fingertip replantation with venous anastomosis (28 and 33 cases with palmar and lateral anastomoses, respectively). Retrospective comparative analyses evaluated surgical technique and function, including operative time; rates of finger survival, venous congestion, and infection; sensation; joint motion; cold intolerance symptom severity (CISS), Disabilities of the Arm, Shoulder, and Hand (DASH), and Vancouver scar scores; and chronic regional pain syndrome (CRPS) rates. Results: There were 33 patients with lateral vein anastomosis and 28 patients with palmar vein anastomosis. The average patient follow-up was 18.2 months. The survival rates did not differ significantly between groups (87.8% (29/33) vs. 85.7% (24/28), p > 0.05); however, the operative time was shorter in the lateral vein group than in the palmar vein group (78.57 ± 7.08 min vs. 67.88 ± 5.77 min, p < 0.05). Venous congestion and infection rates did not differ significantly between groups ( p > 0.05). The replanted finger function, including joint motion, sensation, DASH scores, Vancouver scar scores, and CRPS rates, did not differ significantly between groups ( p > 0.05). However, the CISS score was higher in the palmar vein group than in the lateral vein group (44.39 ± 5.16 vs. 38.09 ± 4.49, p < 0.05). Conclusions: Venous anastomosis with either palmar or lateral veins showed high survival rates and good function in fingertip replantation. The lateral vein had a shorter operative time and benefit to arterial revision and was especially suitable for patients with finger pulp damage.

Morphological integration between seeds and seedlings of Hymenaea courbaril

ABSTRACTMorphological integrations are unknown to forestry seeds. Understanding if seed measurements could predict its future seedlings features is a central question in seedling production. Hymenaea courbaril is an important species in this context and to the applied forestry. Thus, this study aimed to understand how some seedling features, could be related to the seed weight, and be affected by the population origin. The measurements consisted of seedling collar diameter, weight, protophilus area, central and lateral vein. Seed weight consistently varied between the populations in the study. Both populations had higher weight ranges than mentioned in the literature. There was no strong evidence that greater seed weight requires lesser time to germinate, conflicting with previous information. All the measurements presented enough shreds of evidence to be considered different when comparing the populations, except for the protophilus area and lateral vein length. All the studied measurements presented low correlation indexes to seed weight, except for seedling collar diameter, and seedling weight, which presented a moderate correlation. Protophilus elongation pattern was strongly associated with the leaf width when compared to midvein.