Plant genotypic diversity predicts community structure and governs an ecosystem process

Theory predicts, and recent empirical studies have shown, that the diversity of plant species determines the diversity of associated herbivores and mediates ecosystem processes, such as aboveground net primary productivity (ANPP). However, an often-overlooked component of plant diversity, namely population genotypic diversity, may also have wide-ranging effects on community structure and ecosystem processes. We showed experimentally that increasing population genotypic diversity in a dominant old-field plant species, Solidago altissima, determined arthropod diversity and community structure and increased ANPP. The effects of genotypic diversity on arthropod diversity and ANPP were comparable to the effects of plant species diversity measured in other studies.     

Effects of dobutamine, norepinephrine, and vasopressin on cardiovascular function in anesthetized neonatal foals with induced hypotension

OBJECTIVE: To determine the effects of dobutamine, norepinephrine, and vasopressin on cardiovascular function and gastric mucosal perfusion in anesthetized foals during isoflurane-induced hypotension. ANIMALS: 6 foals that were 1 to 5 days of age. PROCEDURES: 6 foals received 3 vasoactive drugs with at least 24 hours between treatments. Treatments consisted of dobutamine (4 and 8 Sang/kg/min), norepinephrine (0.3 and 1.0 Sang/kg/min), and vasopressin (0.3 and 1.0 mU/kg/min) administered IV. Foals were maintained at a steady hypotensive state induced by a deep level of isoflurane anesthesia for 30 minutes, and baseline cardiorespiratory variables were recorded. Vasoactive drugs were administered at the low infusion rate for 15 minutes, and cardiorespiratory variables were recorded. Drugs were then administered at the high infusion rate for 15 minutes, and cardiorespiratory variables were recorded a third time. Gastric mucosal perfusion was measured by tonometry at the same time points. RESULTS: Dobutamine and norepinephrine administration improved cardiac index. Vascular resistance was increased by norepinephrine and vasopressin administration but decreased by dobutamine at the high infusion rate. Blood pressure was increased by all treatments but was significantly higher during the high infusion rate of norepinephrine. Oxygen delivery was significantly increased by norepinephrine and dobutamine administration; O2 consumption decreased with dobutamine. The O2 extraction ratio was decreased following norepinephrine and dobutamine treatments. The gastric to arterial CO2 gap was significantly increased during administration of vasopressin at the high infusion rate. CONCLUSION AND CLINICAL RELEVANCE: Norepinephrine and dobutamine are better alternatives than vasopressin for restoring cardiovascular function and maintaining splanchnic circulation during isoflurane-induced hypotension in neonatal foals.     

One-step fabrication of supramolecular microcapsules from microfluidic droplets

Although many techniques exist for preparing microcapsules, it is still challenging to fabricate them in an efficient and scalable process without compromising functionality and encapsulation efficiency. We demonstrated a simple one-step approach that exploits a versatile host-guest system and uses microfluidic droplets to generate porous microcapsules with easily customizable functionality. The capsules comprise a polymer-gold nanoparticle composite held together by cucurbit[8]uril ternary complexes. The dynamic yet highly stable micrometer-sized structures can be loaded in one step during capsule formation and are amenable to on-demand encapsulant release. The internal chemical environment can be probed with surface enhanced Raman spectroscopy.     

Use of a potentiometric vital dye to determine the effect of the herbicide bromoxynil octanoate on mitochondrial bioenenergetics in Chlamydomonas reinhardtii

BACKGROUND: The aims of the present study were to validate a vital mitochondrial potentiometric staining method in Chlamydomonas reinhardtii and to utilise this method to examine the effect of the herbicide bromoxynil octanoate on mitochondrial potential in this species. A range of stains was investigated, including Rhodamine 123, DASPMI, Mitotracker Green, Mitotracker Orange and JC‐1. RESULTS: Rhodamine 123 (R123) had the highest utility of several candidate stains. Incubation with both 5 and 10 µM carbonyl cyanide 3‐chlorophenylhydrazone caused significant fluorescence collapse [Dunn's post test (40.00, P < 0.01) and (45.49, P < 0.01) respectively], demonstrating that the R123 fluorescence reported mitochondrial potential. The effect of the herbicide bromoxynil octanoate was examined. Exposure to 0.1 mM of bromoxynil resulted in a significant increased mitochondrial fluorescence compared with the baseline (Mann–Whitney U = 222, P < 0.002), while concentrations of 1 mM and greater resulted in significant, almost complete loss of mitochondrial potential [mean fluorescence ratio = 1.193–1.289 (where a ratio of 1 represents total potential loss), Mann–Whitney U = 0.0, P < 0.001 (1 mM ), 0.0, P < 0.0001 (2 mM ), 0.0, P < 0.0001 (5 mM )]. EC₅₀ of the collapse in mitochondrial potential owing to bromoxynil incubation occurred at 0.72 mM , and the mean t₅₀ of bromoxynil octanoate action was 93 s. CONCLUSIONS: R123 is a sensitive potentiometric dye in C. reinhardtii that may find further use in investigations of both mitochondrial bioenergetics in plants and environmental toxicology. Copyright © 2011 Society of Chemical Industry     

Growth and wood basic density of acacia hybrid clones at three locations in Vietnam

Field trials testing a total of 27 clones of the interspecific hybrid Acacia mangium × A. auriculiformis and seedling controls of the parental species were established at Ba Vi and Yen Thanh in the north of Vietnam and Long Thanh in the south. At both Ba Vi and Yen Thanh there were significant (P < 0.001) differences in height and diameter at breast height (DBH) among 22 tested clones at 4 years. At Long Thanh, twelve hybrid clones did not differ significantly in DBH at age 3 years, but did (P < 0.001) at age 5 years. At the two northern sites the acacia hybrid clones had significantly greater DBH than control seedlots of the parental species. At Long Thanh, DBH of the hybrid clones and A. mangium was similar, with a genetically improved seedlot of A. mangium displaying the best DBH. Mean wood basic density at breast height of the acacia hybrid clones was 539 kg m⁻³ at Yen Thanh at age 8 years, and 473 kg m⁻³ at Long Thanh at age 5 years; density for A. mangium at Long Thanh was only slightly lower than the hybrid clones at 461 kg m⁻³. Linear regressions of Pilodyn penetration (PP) at breast height on wood basic density explained 60% of the variance in density of treatments (clones and control seedlots) at Yen Thanh and 36% at Long Thanh. There were significant differences between hybrid clones in PP at all three trial sites. Clonal DBH performance was not strongly correlated across the three trial sites; Pearson correlations of clone mean DBH between pairs of sites ranged from −0.47 to 0.20. Clonal rankings for PP were more stable, with Pearson correlations between pairs of sites ranging from r = 0.71 to 0.78.