Effect of Low pH and Aluminum Toxicity on the Photosynthetic Characteristics of Different Fast-Growing <i>Eucalyptus</i> Vegetatively Propagated Clones

<div><p>Knowing how acid soils and aluminum in soils may limit the growth of <i>Eucalyptus</i> trees in plantations is important because these plantations grow in many tropical and subtropical regions. Seedlings of four vegetatively propagated <i>Eucalyptus</i> clones, <i>E</i>. <i>grandis × E</i>. <i>urophylla</i> ‘GLGU9’(G9), <i>E</i>. <i>grandis × E</i>. <i>urophylla</i> ‘GLGU12’ (G12), E. <i>urophylla × E</i>. <i>camaldulensis</i> ‘GLUC3’ (G3) and <i>E</i>. <i>urophylla</i> ‘GLU4’(G4), were subjected to liquid culture with Hoagland nutrient solution for 40 days, then treated with four different treatments of acid and aluminum for 1 day. The four treatments used either pH 3.0 or 4.0 with or without added aluminum (4.4 mM) in all possible combinations; a control used no added aluminum at pH 4.8. Subsequently, the photosynthetic parameters and morphology of leaves from eucalypt seedlings were determined and observed. The results showed that the tested chlorophyll content, net photosynthetic rate, transpiration rate and water use efficiency were apparently inhibited by aluminum. Under uniform Al concentration (4.4 mM), the Al-induced limitation to photosynthetic parameters increased with pH, indicating acid stimulation to Al toxicity. Among all treatments, the most significant reduction was found in the combination of pH 3.0 and 4.4 mM Al. The photosynthetic and transpiration rates showed similar trends with G9 > G12 > G3 > G4, suggesting that G9 and G12 had higher Al-tolerance than other two clones. Microscopic observation revealed changes in leaf morphology when exposed to Al stress; for example, a reduced thickness of leaf epidermis and palisade tissue, the descendant palisade tissue/spongy tissue ratio and leaf tissue looseness. Overall, the acid and aluminum stress exerted negative effects on the photosynthetic activity of eucalypt seedlings, but the differences in tolerance to Al toxicity between the clones were favorable, offering potential to improve <i>Eucalyptus</i> plantation productivity by selecting Al tolerant clones.</p></div

Changes in seedling chlorophyll content of four eucalypt clones under different acid aluminum treatments.

<p>G3 represents <i>E</i>. <i>urophylla × E</i>. <i>camaldulensis</i> ‘GLUC3’; G4, <i>E</i>. <i>urophylla</i> ‘GLU4’; G9, <i>E</i>. <i>grandis × E</i>. <i>urophylla</i> ‘GLGU9’; G12, <i>E</i>. <i>grandis × E</i>. <i>urophylla</i> ‘GLGU12’. Treatments: K_0-3, treatment with 0 mM Al³⁺, pH 3.0; K_4.4–3, 4.4 mM Al³⁺, pH 3.0; K_0-4, 0 mM Al³⁺, pH 4.0; K_4.4–4, 4.4 mM Al³⁺, pH 4.0; CK, control treatment, 0 mM Al³⁺, pH 4.8. Capital letters represent significant differences between treatments within an eucalypt clone at the 0.01 level, small letters are at the 0.05 level, n = 3.</p

Changes in transpiration rates of four eucalypt clones under different acid aluminum treatments.

<p>G3 represents <i>E</i>. <i>urophylla × E</i>. <i>camaldulensis</i> ‘GLUC3’; G4, <i>E</i>. <i>urophylla</i> ‘GLU4’; G9, <i>E</i>. <i>grandis × E</i>. <i>urophylla</i> ‘GLGU9’; G12, <i>E</i>. <i>grandis × E</i>. <i>urophylla</i> ‘GLGU12’.Treatments: K_0-3, treatment with 0 mM Al³⁺, pH 3.0; K_4.4–3, 4.4 mM Al³⁺, pH 3.0; K_0-4, 0 mM Al³⁺, pH 4.0; K_4.4–4, 4.4 mM Al³⁺, pH 4.0; CK, control treatment, 0 mM Al³⁺, pH 4.8. Capital letters represent significant differences between treatments within an eucalypt clone at the 0.01 level, small letters are at the 0.05 level, n = 3.</p

Data_Sheet_1_Phenomenological characteristics of autobiographical future thinking in nurses with burnout: a case-control study.doc

ObjectiveNurses constitute the largest group of healthcare workers worldwide, and job burnout is very common among them. This study aims to explore abnormal future thinking in nurses with burnout. Additionally, the study investigates whether these manifestations worsen as burnout progresses.MethodsThe study was conducted in inpatient ward nurses at a tertiary hospital in Hangzhou, China. In the first phase, two group of nurses were recruited: nurses with burnout (N = 70) and nurses without burnout (N = 70). In the second phase, three groups were recruited according to the burnout levels: mild burnout (N = 43), moderate burnout (N = 42) and severe burnout (N = 43). Data on job burnout were obtained using the Chinese Maslach Burnout Inventory. The Sentence Completion for Events in the Future Test (SCEFT) was employed to measure the content of future thinking, which was evaluated by two raters in terms of the specificity, emotional valence, and concrete content of the imagined future events. The proportions of specific types of events among all the produced events were calculated.ResultsThe results revealed that nurses with burnout, compared to nurses without burnout, imagined fewer specific future events, positive events, and events related to relationships and achievement. They also had more omissions. As the level of burnout increased, their impairment in future thinking worsened. Furthermore, the results also revealed that the scores of emotional exhaustion, depersonalization, and personal accomplishment had significant correlations with the proportions of positive events and events related to relationships and achievement/mastery in nurses’ future thinking content.ConclusionThe future thinking ability of nurses with burnout was impaired, and this impairment worsened as the symptoms of burnout progressed. The findings of the present study have important implications for nurse caring and advocate effective interventions targeting positive future thinking to mitigate nurses’ burnout.</p