玉米种子萌发成苗不同阶段需水阈值的研究

用渗透势不同的聚乙二醇（ＰＥＧ）６０００模拟外界环境水分条件,对玉米不同品种的种子在萌动、萌发及成苗三个阶段需水的量化研究表明,种苗的抗旱性随吸水进程的推进而减弱;种子在萌动、萌发及胚芽伸长至一定长度的时间（ｔ）与外界环境水势（ｗ）之间存在着１／ｔ＝ａ＋ｂｗ的关系,据此推算出不同品种在不同成苗阶段的需水阈值,发现不同品种在同一成苗过程中对环境水分条件的反应不同,它们的抗旱性也不同。     

Combined effect of cyprid age and lipid content on larval attachment and metamorphosis of Balanus amphitrite darwin

Various algal diets of different lipid content and composition were used to rear batches of naupliar larvae of Balanus amphitrite. The cyprids in these larval batches differed in lipid content and were used to investigate the combined effect of cyprid lipid content and cyprid age on attachment and metamorphosis. For this purpose, cyprids were aged for 0,3 and 6 d at 8°C prior to utilization in laboratory attachment assays. The percentage attachment of cyprids with similar lipid content differed significantly among the three age categories. A strong and a weak positive relationship between cyprid lipid content and attachment were monitored in young and old cyprids, respectively. A significant interaction (two‐way ANOVA) between cyprid age and lipid content was observed, indicating that these factors jointly affect larval attachment and metamorphosis in B. amphitrite from the beginning of the cyprid stage.     

Dynamics of Maize Carbon Contribution to Soil Organic Carbon in Association with Soil Type and Fertility Level

Soil type and fertility level influence straw carbon dynamics in the agroecosystems. However, there is a limited understanding of the dynamic processes of straw-derived and soil-derived carbon and the influence of the addition of straw carbon on soil-derived organic carbon in different soils associated with different fertility levels. In this study, we applied the in-situ carborundum tube method and ¹³C-labeled maize straw (with and without maize straw) at two cropland (Phaeozem and Luvisol soils) experimental sites in northeast China to quantify the dynamics of maize-derived and soil-derived carbon in soils associated with high and low fertility, and to examine how the addition of maize carbon influences soil-derived organic carbon and the interactions of soil type and fertility level with maize-derived and soil-derived carbon. We found that, on average, the contributions of maize-derived carbon to total organic carbon in maize-soil systems during the experimental period were differentiated among low fertility Luvisol (from 62.82% to 42.90), high fertility Luvisol (from 53.15% to 30.00%), low fertility Phaeozem (from 58.69% to 36.29%) and high fertility Phaeozem (from 41.06% to 16.60%). Furthermore, the addition of maize carbon significantly decreased the remaining soil-derived organic carbon in low and high fertility Luvisols and low fertility Phaeozem before two months. However, the increasing differences in soil-derived organic carbon between both soils with and without maize straw after two months suggested that maize-derived carbon was incorporated into soil-derived organic carbon, thereby potentially offsetting the loss of soil-derived organic carbon. These results suggested that Phaeozem and high fertility level soils would fix more maize carbon over time and thus were more beneficial for protecting soil-derived organic carbon from maize carbon decomposition.     

Roles of rootstocks and scions in aluminum-tolerance of <Emphasis Type="Italic">Citrus</Emphasis>

Four scion-rootstock combination [i.e., X/X and X/SP, ‘Xuegan’ (Citrus sinensis) grafted on ‘Xugan’ and ‘Sour pummelo’ (Citrus grandis), respectively, and SP/X and SP/SP, ‘Sour pummelo’ grafted on ‘Xuegan’ and ‘Sour pummelo’, respectively] plants were treated for 18 weeks with 0 (?Al) or 1.2 mM AlCl₃·6H₂O (+Al). Thereafter, leaf, stem and root concentrations of phosphorus and aluminum (Al), leaf and root levels of organic acids (OAs), Al-induced release of OA anions (i.e., malate and citrate), photosynthesis and chlorophyll a fluorescence (OJIP) transients were measured. Al-induced decrease of photosynthesis and damage of photosynthetic electron transport chain were less pronounced in X/X and X/SP leaves than in SP/SP and SP/X leaves, which might be related with the higher Al-induced root efflux of OA anions and leaf P concentration. C. sinensis rootstock alleviated the influences of Al-toxicity on leaf photosynthetic electron transport chain by enhancing Al-induced release of root OA anions, hence lessening Al-induced photosynthesis inhibition in SP/X plants, while the reverse was the case for C. grandis rootstock in X/SP plants. In conclusion, the tolerance of grafted Citrus plants to Al depends on the scion as well as rootstock genotype, and the scion-rootstock interaction.     

Retinal Arteriolar Morphometry Based on Full Width at Half Maximum Analysis of Spectral-Domain Optical Coherence Tomography Images

Objectives

In this study, we develop a microdensitometry method using full width at half maximum (FWHM) analysis of the retinal vascular structure in a spectral-domain optical coherence tomography (SD-OCT) image and present the application of this method in the morphometry of arteriolar changes during hypertension.

Methods

Two raters using manual and FWHM methods measured retinal vessel outer and lumen diameters in SD-OCT images. Inter-rater reproducibility was measured using coefficients of variation (CV), intraclass correlation coefficient and a Bland-Altman plot. OCT images from forty-three eyes of 43 hypertensive patients and 40 eyes of 40 controls were analyzed using an FWHM approach; wall thickness, wall cross-sectional area (WCSA) and wall to lumen ratio (WLR) were subsequently calculated.

Results

Mean difference in inter-rater agreement ranged from -2.713 to 2.658 μm when using a manual method, and ranged from -0.008 to 0.131 μm when using a FWHM approach. The inter-rater CVs were significantly less for the FWHM approach versus the manual method (P < 0.05). Compared with controls, the wall thickness, WCSA and WLR of retinal arterioles were increased in the hypertensive patients, particular in diabetic hypertensive patients.

Conclusions

The microdensitometry method using a FWHM algorithm markedly improved inter-rater reproducibility of arteriolar morphometric analysis, and SD-OCT may represent a promising noninvasive method for in vivo arteriolar morphometry.     

Skin aging caused by intrinsic or extrinsic processes characterized with functional proteomics

The skin provides protection against environmental stress. However, intrinsic and extrinsic aging causes significant alteration to skin structure and components, which subsequently impairs molecular characteristics and biochemical processes. Here, we have conducted an immunohistological investigation and established the proteome profiles on nude mice skin to verify the specific responses during aging caused by different factors. Our results showed that UVB‐elicited aging results in upregulation of proliferating cell nuclear antigen and strong oxidative damage in DNA, whereas chronological aging abolished epidermal cell growth and increased the expression of caspase‐14, as well as protein carbonylation. Network analysis indicated that the programmed skin aging activated the ubiquitin system and triggered obvious downregulation of 14‐3‐3 sigma, which might accelerate the loss of cell growth capacity. On the other hand, UVB stimulation enhanced inflammation and the risk of skin carcinogenesis. Collectively, functional proteomics could provide large‐scale investigation of the potent proteins and molecules that play important roles in skin subjected to both intrinsic and extrinsic aging.     

ER-localized adenine nucleotide transporter ER-ANT1: an integrator of energy and stress signaling in rice

Most environmental perturbations have a direct or indirect deleterious impact on photosynthesis, and, in consequence, the overall energy status of the cell. Despite our increased understanding of convergent energy and stress signals, the connections between photosynthesis, energy and stress signals through putative common nodes are still unclear. Here we identified an endoplasmic reticulum (ER)-localized adenine nucleotide transporter1 (ER-ANT1), whose deficiency causes seedling lethality in air but viable under high CO₂, exhibiting the typical photorespiratory phenotype. Metabolic analysis suggested that depletion of ER-ANT1 resulted in circadian rhythm disorders in sucrose synthesis and induced sucrose signaling pathways, indicating that the ER is involved in the regulation of vital energy metabolism in plants. In addition, the defect of ER-ANT1 triggers ER stress and activates the unfolded protein response in plant cells, suggesting ER stress and photorespiration are closely linked. These findings provide an important evidence for a key role of ER-localized ER-ANT1 in convergent energy and stress signals in rice. Our findings support the idea that ATP is a central signal involved in the plant response to a variety of stresses.     

类芒齿黄芪地下部分化学成分研究

为了解类芒齿黄芪( Astragalus camptodontoides)主要化学成分,从其地下部分甲醇提取物的乙酸乙酯部位分离出19个单体化合物,通过现代波谱分析及理化性质等手段分别鉴定为异补骨脂黄酮(1),4′-hydroxy-isolonchocarpin (2),5-去氧山豆根黄酮(3),shinflavanone (4),khonklonginols H (5),4′-O-methylpreglabridin (6),3′-hydroxy-4′-O-methylglabridin (7),4′-O-methylglabridin (8),8-prenyl-phaseollinisoflavan (9),xambioona (10),光甘草酚(11),粗毛甘草素H (12),methylnissolin (13),邻苯二甲酸异丁酯(14),邻苯二甲酸丁酯异丁酯(15),β-谷甾醇(16),胡萝卜苷(17),齐墩果酸(18),(2S,3S,4R,9E)-1,3,4-trihydroxy-2-[(2′R)-2′- hydr-oxytetraco-sanoylamino]-9-octadecene (19)。化合物1~19均为首次从该植物中获得,化合物1~7为首次从黄芪属(Astraga-lus)植物中分离得到。