Smaller stomata require less severe leaf drying to close: A case study in Rosa hydrida

Stomata formed at high relative air humidity (RH) close less as leaf dries; an effect that varies depending on the genotype. We here quantified the contribution of each stomatal response characteristic to the higher water loss of high RH-grown plants, and assessed the relationship between response characteristics and intraspecific variation in stomatal size. Stomatal size (length multiplied by width), density and responsiveness to desiccation, as well as pore dimensions were analyzed in ten rose cultivars grown at moderate (60%) or high (85%) RH. Leaf morphological components and transpiration at growth conditions were also assessed. High growth RH resulted in thinner (11%) leaves with larger area. A strong positive genetic correlation of daytime and nighttime transpiration at either RH was observed. Stomatal size determined pore area (r = 0.7) and varied by a factor of two, as a result of proportional changes in length and width. Size and density of stomata were not related. Following desiccation, high RH resulted in a significantly lower (6–19%) decline of transpiration in three cultivars, whereas the relative water content (RWC) of high RH-expanded leaflets was lower (29–297%) in seven cultivars. The lower RWC of these leaflets was caused by (a) higher (33–72%) stable transpiration and/or (b) lower (12–143%) RWC at which this stable transpiration occurred, depending on the cultivar. Stomatal size was significantly correlated with both characteristics (r = 0.5 and -0.7, respectively). These results indicate that stomatal size explains much of the intraspecific variation in the regulation of transpiration upon water deprivation on rose.     

Early responses to cadmium of two poplar clones that differ in stress tolerance

Soil cadmium (Cd) contamination is becoming a matter of great global concern. The identification of plants differentially sensitive to Cd excess is of interest for the selection of genotype adaptive to grow and develop in polluted areas and capable of ameliorating or reducing the negative environmental effects of this toxic metal. The two poplar clones I-214 (Populus × canadensis) and Eridano (Populus deltoides × maximowiczii) are, respectively, tolerant and sensitive to ozone (O₃) exposure. Because stress tolerance is mediated by an array of overlapping defence mechanisms, we tested the hypothesis that these two clones differently sensitive to O₃ stress factor also exhibit different tolerance to Cd. With this purpose, an outdoor pot experiment was designed to study the responses of I-214 and Eridano to the distribution of different Cd solutions enriched with CdCl₂ (0, 50 and 150 μM) for 35 days. Changes in leaf area, biomass allocation and Cd uptake, photosynthesis, chlorophyll fluorescence, leaf concentration of nutrients and pigments, hydrogen peroxide (H₂O₂) and nitric oxide (NO) production and thiol compounds were investigated. The two poplar clones showed similar sensitivity to excess Cd in terms of biomass production, photosynthesis activity and Cd accumulation, though physiological and biochemical traits revealed different defence strategies. In particular, Eridano maintained in any Cd treatment the number of its constitutively wider blade leaves, while the number of I-214 leaves (with lower size) was reduced. H₂O₂ increased 4.5- and 13-fold in I-214 leaves after the lowest (L) and highest (H) Cd treatments, respectively, revealing the induction of oxidative burst. NO, constitutively higher in I-214 than Eridano, progressively increased in both clones with the enhancement of Cd concentration in the substrate. I-214 showed a more elevated antioxidative capacity (GSH/GSSG) and higher photochemical efficiency of PSII (F_v/F_m) and de-epoxidation degree of xantophylls-cycle (DEPS). The glutathione pool was not affected by Cd treatment in both clones, while non-protein thiols and phytochelatins were reduced at L Cd treatment in I-214. Overall, these two clones presented high adaptability to Cd stress and are both suitable to develop and growth in environments contaminated with this metal, thus being promising for their potential use in phytoremediation programmes.     

卡瑞利珠单抗联合标准二线化疗对晚期食管鳞癌患者肿瘤标志物和外周血NLR、LMR的影响及其预后的影响因素分析

摘要 目的：探讨卡瑞利珠单抗联合标准二线化疗对晚期食管鳞癌患者肿瘤标志物和外周血中性粒细胞/淋巴细胞比值（NLR）、淋巴细胞/单核细胞比值（LMR）的影响,并分析影响晚期食管鳞癌预后的因素。方法：选择2019年8月至2021年8月安徽医科大学附属巢湖医院收治的80例晚期食管鳞癌患者,根据治疗方法将其分为对照组（40例）采用标准二线化疗治疗,观察组（40例）采用卡瑞利珠单抗联合标准二线化疗治疗。比较两组疗效、血清肿瘤标志物以及外周血NLR、LMR水平以及安全性差异。绘制Kaplan-Meier曲线,分析不同治疗方案晚期食管鳞癌患者总生存期（OS）期差异,多因素Cox回归分析影响晚期食管鳞癌患者预后的因素。结果：观察组客观缓解率（ORR）、疾病控制率（DCR）高于对照组（P＜0.05）;两组治疗后血清糖类抗原125（CA125）、糖类抗原199（CA199）、癌胚抗原（CEA）、糖类抗原724（CA724）以及外周血NLR水平均较治疗前降低（P＜0.05）,外周血LMR较治疗前增高（P＜0.05）,观察组治疗后血清CA125、CA199、CEA、CA724水平以及外周血NLR低于对照组（P＜0.05）,外周血LMR水平高于对照组（P＜0.05）;两组不良反应发生率比较无差异（P＞0.05）。观察组中位无进展生存期（PFS）、OS生存期长于对照组（P＜0.05）。多因素Cox回归分析结果显示TNM分期Ⅳ期、远处转移、高NLR是影响晚期食管鳞癌患者预后的危险因素（P＜0.05）,高LMR、卡瑞利珠单抗联合标准二线化疗是保护因素（P＜0.05）。结论：卡瑞利珠单抗联合标准二线化疗可提高晚期食管磷癌临床疗效,降低血清肿瘤标志物以及外周血NLR水平,提高外周血LMR水平,TNM分期Ⅳ期、远处转移、高NLR是影响晚期食管鳞癌患者预后的危险因素,高LMR、卡瑞利珠单抗联合标准二线化疗是其保护因素。     

外周血中常见血液学参数对乳腺癌预后评估价值的研究进展

在世界范围内,乳腺癌是最常见的女性恶性肿瘤,严重危害人民健康。最近的流行病学和临床研究发现炎性反应与乳腺肿瘤有着一定的联系。炎症构成肿瘤微环境的一部分,炎性细胞的变化影响着肿瘤的进展,包括乳腺癌细胞增殖,侵袭,免疫力降低,转移等。检验外周静脉血中的白细胞、中性粒细胞、淋巴细胞、单核细胞、血小板以及衍生出的中性粒细胞/淋巴细胞比值(NLR)、派生中性粒细胞/淋巴细胞(d-NLR)、血小板/淋巴细胞比值(PLR)、淋巴细胞/单核细胞比值(LMR)等可以反映许多恶性肿瘤细胞的炎性状态。深入研究外周血中常见的标记物与乳腺癌的治疗及预后的关系,为临床医师提供有价值的参考信息,将具有重要的临床意义和应用前景。本文就外周血中常见的标记物进行相关论述,以期为乳腺癌的治疗及预后提供一个新的方法。     

Leaf traits as indicators of limiting growing conditions for lettuce (Lactuca sativa)

Lettuce growth under unstressed conditions was compared to growth under four limiting conditions, i.e. no phosphorus fertilization (0_P), no nitrogen fertilization (0_N), low light (LR) and water stress (WR) over two different growing periods. We investigated the adaptive changes in terms of the morphological and physiological leaf traits, identifying stress‐specific and ‘stable’ indicators suitable for use in breeding programmes. The plants subjected to the WR treatments had lower leaf expansion and specific leaf area (SLA), as well as lower soil–plant analysis development (SPAD) values, stomatal conductance (POR), water index (WI) and leaf temperature (TIR) compared with plants in the unstressed CONTROL. Low light increased the leaf area (LA), SLA and leaf mass ratio (LMR). The 0_N treatment induced a general reduction in the normalised difference vegetation index (NDVI) values, as well as strong changes in LMR and SLA. In general, 0_P induced less pronounced effects than the other treatments. Principal component analysis indicated that the stable and suitable selection indicators of adaptive changes for low nitrogen and low light conditions were LA, SLA, leaf area per unit total plant mass (LAR), LMR, SPAD and POR, while SPAD, POR, TIR and WI were suitable indicators for drought.     

Optimal allocation of resources in response to shading and neighbours in the heteroblastic species, Acacia implexa

BACKGROUND AND AIMS: Heteroblasty is an encompassing term referring to ontogenetic changes in the plant shoot. A shaded environment is known to affect the process of heteroblastic development; however, it is not known whether crowded or high density growing conditions can also alter heteroblasty. Compound leaves of the shade-intolerant Acacia implexa allocate less biomass per unit photosynthetic area than transitional leaves or phyllodes and it is hypothesized that this trait will convey an advantage in a crowded environment. Compound leaves also have larger photosynthetic capture area - a trait known to be advantageous in shade. This studied tested the hypothesis that more compound leaves will be developed under shade and crowded environments. Furthermore, this species should undergo optimal allocation of biomass to shoots and roots given shaded and crowded environments. METHODS: A full factorial design of irradiance (high and low) and density levels (high, medium and low) on three populations sourced from varying rainfall regions (high, medium and low) was established under controlled glasshouse conditions. Traits measured include the number of nodes expressing a compound leaf, biomass allocation to shoots and roots, and growth traits. Key Results A higher number of nodes expressed a compound leaf under low irradiance and in high density treatments; however, there were no significant interactions across treatments. Phenotypes strongly associated with the shade avoidance syndrome were developed under low irradiance; however, this was not observed under high density. There was no significant difference in relative growth rates across light treatments, but growth was significantly slower in a crowded environment. Conclusions Heteroblastic development in Acacia can be altered by shade and crowded environments. In this experiment, light was clearly the most limiting factor to growth in a shaded environment; however, in a crowded environment there were additional limiting resources to growth.