‘72杨’韧皮部的构造与理化性能

将‘72杨’、杉木和毛竹的木质部进行对比试验,观察并测试‘72杨’韧皮部的解剖构造以及理化特性,为其高值化利用提供基础数据。使用场发射环境扫描电镜、X射线衍射仪、傅里叶变换红外光谱仪等设备和NREL标准对‘72杨’韧皮部的微观结构、结晶度、化学成分等物化性质进行测定与分析。研究结果表明,‘72杨’韧皮部中韧皮薄壁细胞和筛管分子占细胞总面积的(81.9±1.8)%,结构相对简单。‘72杨’韧皮部气干密度为0.358 g/cm3,绝干密度为0.321 g/cm3;而木质部的相应密度较高,分别为0.497和0.482 g/cm3;‘72杨’韧皮部结晶度仅为19.4%,比木质部低8.7%。‘72杨’韧皮部纤维素、半纤维素、木质素的含量分别为28.7%,11.1%,24.1%,均低于木质部中相应成分的含量,且木质化程度低,半纤维素以木糖为主。此外,由红外谱图发现‘72杨’韧皮部含有单宁、酚类、胼胝质等物质。‘72杨’韧皮部具有低密多孔、结构疏松、结晶度低、木质素含量低、抽提物含量高等特点。因此,‘72杨’韧皮部特别有利于机械(能耗低)或化学(抗降解屏障低)降解以及物化改性(多孔、可及性强),可提取酚类、单宁、胼胝质等物质用于工业应用,研究结果可为‘72杨’韧皮部的高值化利用提供重要的理论依据。     

Knockdown of HMGA2 gene inhibits TGF-β1-induced human embryonic lung fibroblast growth and collagen synthesis

AIM: To investigate the effects of high mobility group A2(HMGA2) gene knockdown on the cell viability, apoptosis, collagen synthesis and oxidative stress of human embryonic lung fibroblast (HELF) induced by transforming growth factor-β1 (TGF-β1). METHODS: The HELF were divided into blank group, TGF-β1 group,negative control (NC) group and HMGA2 siRNA(si-HMGA2) group. The protein levels of HMGA2, AKT and p-AKT were determined by Western blot. The cell viability and apoptotic rate was analyzed by MTT assay and flow cytometry,respectively. The mRNA expression of collagen I (COL-Ⅰ) and COL-Ⅲ was detected by RT-qPCR. DCFH-DA was used to detect the content of reactive oxygen species (ROS). RESULTS: Compared with blank group, the protein levels of HMGA2 and p-AKT, the cell viability, the mRNA expression of COL-Ⅰ and COL-Ⅲ in TGF-β1 group were significantly increased, but the apoptotic rate and ROS level were significantly decreased (P<0.05). Compared with TGF-β1 group, the protein levels of HMGA2 and p-AKT, the cell viability, the mRNA expression of COL-Ⅰ and COL-Ⅲ in si-HMGA2 group were significantly decreased, but the apoptotic rate and ROS level were significantly increased (P<0.05). CONCLUSION: Knockdown of HMGA2 gene expression decreases the viability and collagen synthesis, and promotes apoptosis and ROS production of human embryonic lung fibroblasts induced by TGF-β1. The mechanism may be related to down-regulation of PI3K/AKT signaling pathway.     

水稻籼爪交和粳爪交杂种优势的研究:Ⅳ.籼爪交杂种品质性状的杂种优势分析

长沙生态条件下籼爪交杂交稻在整精米率、精米长宽比、垩白粒率、垩白面积率、碱消值和直链淀粉含量方面表现为正向超亲优势；在精米长宽比、碱消值和直链淀粉含量方面表现为正向对照优势。三亚生态条件下籼爪交杂交稻在糙米率、总精米率、情米长宽比和胶稠度方面表现出正向对照优势，三亚籼爪交杂交稻的糙米率、总精米率、整精米率、精米长宽比和胶稠度对照优势极显著高于长沙相应性状的对照优势；三亚的垩白粒率对照优势显著高于长沙的垩白粒率对照优势；三亚的碱消值和直链淀粉含量对照优势显著低于长沙相应性状的对照优势。     

潮土小麦碳氮含量对长期不同施肥模式的响应

【目的】以潮土21年长期定位试验为基础,分析不同施肥模式下冬小麦不同生育期的地上部生物量、碳氮含量、碳氮比及碳氮积累量,探讨冬小麦碳氮含量对不同施肥模式的响应规律。【方法】试验包括不施肥(CK)、单施氮肥(N)、施氮磷肥(NP)、施氮钾肥(NK)、氮磷钾配施(NPK)、氮磷钾肥配施有机肥(NPKM)、施氮磷钾肥及玉米秸秆还田(NPKS)7个处理。在2011 2012年冬小麦生长季,分别采集越冬、拔节、灌浆、成熟四个生育时期地上部植株样品,利用Euro Vector EA3000型元素分析仪对小麦植株样品的全碳、全氮含量进行测定。【结果】NPK、NPKM和NPKS处理均能显著提高各生育期小麦地上部干重,其中NPKM处理小麦地上部干重在越冬、拔节、灌浆、成熟期分别比CK提高了111%、194%、238%、206%,除越冬期外,等量氮肥条件下,NPK、NPKM和NPKS 3个处理间小麦同一生育期地上部干重无显著差异,说明与氮磷钾配施相比,有机无机配施与秸秆还田这两种措施并不能显著提高小麦地上部生物量;小麦地上部碳含量受不同施肥影响很小,不同生育期小麦地上部碳含量平均值为410 g/kg;小麦成熟期地上部氮含量以N和NK处理最高,分别达到19.4和18.1 g/kg,其中N处理小麦地上部氮含量分别比NPKM和NPKS处理高52%和66%。随着生育期的推移,各处理小麦氮含量逐渐降低,总体表现为越冬期拔节期灌浆期≥成熟期;在整个生育期中各施肥处理碳含量基本保持不变而氮含量呈逐渐下降趋势,这就使得各施肥处理地上部分C/N比随生育期的推移呈逐渐增加趋势;不同施肥下小麦碳积累量差异性和地上部干物质重差异性规律一致,而不同施肥下地上部氮积累量差异性不同于干物质重的差异性,以NP处理最高,达545 kg/hm2,分别比NPKM和NPKS处理高61%和68%。【结论】施肥方式不能显著改变小麦碳含量但能影响氮含量,因此小麦生物量大小决定了其碳的积累量,相应地,C/N比大小则由氮含量决定。氮磷钾配施、有机无机配施及秸秆还田处理下,小麦具有较高的生物量从而具有较高的碳氮积累量,这有利于增加农田系统碳、氮积累,提升土壤碳、氮肥力。     

Interaction Between Salinity Stress and Verticillium Wilt Disease in Three Pistachio Rootstocks in a Calcareous Soil

ABSTRACT

The interaction between soil salinity and infection caused by Verticillium dahliae was studied in pistachio (Pistacia vera) in a greenhouse experiment. Treatments consisted of 0, 1400, 2800, and 4200 mg sodium chloride (NaCl) kg^{? 1} soil and three rootstocks (Sarakhs, Badami, and Qazvini cultivars). They were gradually exposed to salinity stress before and/or after root inoculation with a water suspension of 10⁷ conidia/mL of a pistachio isolate of V. dahliae. Salt stress significantly increased rootstock shoot and root colonization by V. dahliae. All rootstocks were susceptible to V. dahliae, but symptoms of the disease appeared earlier in Sarakhs, a salt sensitive cultivar. Moreover, salinity and V. dahliae interaction increased the concentrations of sodium (Na), potassium (K) and chloride (Cl), but decreased the K/Na ratio in all rootstocks. Shoot and root tissues of inoculated Sarakhs and Qazvini (a salt tolerant) contained the highest and the lowest concentrations of Na, K,and Cl, respectively. In salinity treatments, shoot and root dry weight of all rootstocks decreased as compared with controls. Sarakhs showed smaller shoot and root dry weight than Qazvini and Badami. Also, increasing the NaCl level increased accumulation of Na, K, and Cl in shoot and root of the rootstocks. Sarakhs showed higher concentrations of ions in the shoot and root. Based on shoot and root dry weights and ion accumulation, Sarakhs and Qazvini were susceptible and tolerant to salinity, respectively.     

玉米/蒜苗套作系统中土壤微生物和土壤酶状况分析

对玉米蒜苗套作根区进行隔膜、隔网和无隔处理以及各自单作处理,通过处理间的相互比较,分析影响套作产量的主要土壤因素。结果表明:套作蒜苗土壤微生物上升其主要原因是根系间的非接触物质交换;套作玉米除此外,地上部环境的改变也使根部土壤微生物数量上升。根系间的非接触效应还使蒜苗、玉米土壤过氧化氢酶、蔗糖酶活性提高,而环境因素的改变也使玉米过氧化氢酶,蒜苗脲酶活性提高。相关性分析表明:微生物对蒜苗根际土壤酶活性的影响大于对玉米土壤酶的影响。     

Identification of double/twin bolled and bicolor unit ‘cluster’ in <Emphasis Type="Italic">Gossypium hirsutum</Emphasis> L. cotton

Cultivated tetraploid Gossypium hirsutum L. (Malvaceae) cotton has been characterized as having one flower at a primordia. In a strain (CSH-13) of Gossypium hirsutum cotton, four plants out of 103 had two to three double bolls or twin bolls/plant during 2003–2004 crop season at CICR regional station, Sirsa, Haryana, India. Progeny evaluation in 2004 and 2005 crop seasons indicated that plants raised from seeds harvested from double bolls/twin bolls produced plants bearing double bolls only and plant progeny raised from the seed of single bolls from these mutant plants produced two to three double bolls per plant similar to the parent. Progeny testing revealed that double boll formation is the result of spontaneous mutation and environment does not influence its expression. The mutant is early in maturity by 10–15 days, naked seeded and possesses comparable agronomic characters with normal plants. Another spontaneous mutant of Gossypium hirsutum having more than three appendages originating from primordia.: four bolls one leaf, three bolls one leaf, two bolls two leaves, one boll three leaves were obtained from the population of CISV-13 strain in crop season 2003. These appendage groups have been described as bicolor unit by Clemens Bayer, [Zur Infloreszenzmorphologie der Malvales. Dissertations Botany 212 (1994)] and cluster mutant by Russell and Luther [J Cott Sci 6 (2002) 115]. One to three bolls in a cluster or bicolor unit were observed without formation of seeds and lint. About one-third of the total bolls on the mutant plant were of this type. In progeny testing during 2004 and 2005 crop seasons, this mutant produced plants exclusively with more than three appendages revealing that plants identified in 2003 were due to spontaneous mutation. This mutant was also early and naked seeded. Many of the other characters of the mutant plants were comparable with the wild type plants of the strain. Both the mutants were observed having economic impact due to their better yielding ability as compare to respective parents.     

Tillage effects on soil organic matter in density fractions of a Cerrado Oxisol

Reclamation of Brazilian cerrados (savannas) has been intensified in the last decades, with implications for soil quality and soil organic matter (SOM) dynamics. Studying the impact of different tillage systems is essential to define better strategies for land use in Cerrado, which may favor C sequestration and improve soil quality. We used density fractionation and ¹³C natural abundance to assess changes in SOM in an Oxisol previously under a cerrado sensu-stricto following 30 years of cultivation. The objectives of the study were to: (i) evaluate the long-term impact of tillage systems on SOM stocks in a Dark Red Latosol (Oxisol) from the Cerrado Biome, and (ii) better understand the dynamics of SOM in different density fractions of this soil. Cultivation led to compaction, which significantly increased soil bulk density. This resulted in the systematic overestimation of C and N stocks in cultivated areas when compared to the natural cerrado. Conversion of the cerrado into cropland using plow tillage (PT) or no-tillage (NT) system did not alter the total C (100 Mg ha⁻¹) and N (7 Mg ha⁻¹) stocks in the first 45 cm depth at the end of 30 years of cultivation. However, about 22% of the total C was replaced by C from maize. The relative replacement of C decreased following the order: free light fraction (F-LF)>heavy fraction (HF)>occluded light fraction (O-LF). The low substitution in the O-LF was attributed to a possible presence of charcoal. Converting cerrado into cropland significantly decreased F-LF quantity. The proportions of C replacement in this fraction were higher in PT than NT, suggesting a faster turnover in PT. Nevertheless, because most C (95%) was held in the HF, C dynamics in the whole soil were controlled by the behavior of this fraction. The maintenance of C levels even at the end of 30 years of cultivation and the lack of differentiation between NT and PT were attributed to the high clay contents and Fe+Al oxi-hydroxides concentrations of the studied soil as well as to a sufficient C supply by the maize crop.     

REDUCING NITRATE CONTENT IN LETTUCE BY PRE-HARVEST CONTINUOUS LIGHT DELIVERED BY RED AND BLUE LIGHT-EMITTING DIODES

Effect of pre-harvest continuous light with different red/blue ratio on photon flux density (R/B ratio) on reducing nitrate accumulation was studied by growing lettuce (Lactuca sativa L.) under continuous illumination delivered by light-emitting diodes (LEDs). Results show that nitrate concentration decreased by 1648.0–2061.1 mg kg^?1 in leaf blade and 962.9–2090.3 mg kg^?1 in petiole, accompanied by a dramatic increase in soluble sugar content. Compared with monochromatic red light treatment, the decrease in nitrate concentration and increase in soluble sugar content in lettuce under mixed red and blue light were more pronounced. The lowest nitrate concentration was observed in the treatment with R/B ratio of 4. It's concluded that pre-harvest exposure to 48?h continuous LED light could effectively reduce nitrate accumulation in lettuce and this process is strongly affected by R/B ratio of light. This study may provide new perspective for pre-harvest quality management of vegetable, especially in commercial leaf vegetable production under artificial lighting.     

Impacts of the nitrogen application on productivity and nutrients concentrations of the corn-Congo grass intercropping system in the dry season

ABSTRACT

The corn-grass intercropping system began to be used in the dry season, as it provides increased straw production for the no-tillage system. However, corn and grass are plants demanding in nitrogen. The corn cultivated in the dry season is called out-of-season corn in Brazil. The objective of this study was to evaluate the productivity and nutrients concentrations of out-of-season corn and Congo-grass intercropped in the no-tillage system, as a function of the nitrogen rates applied in sidedressing. The treatments were four nitrogen rates, 0, 30, 60 and 90?kg?ha^?1. The experimental design was randomised complete blocks with four replicates. The experimental period corresponded to the harvests of 2015 and 2016. There were evaluated: corn grain yield, dry mass production and nutrient concentration in the shoots of the plants intercropped. The evaluations were carried out at the physiological maturity stage of the corn and at the time of desiccation of the grass. Nitrogen increased grain yield and dry mass production of the plants intercropped. Nitrogen maximised the magnesium concentration in out-of-season corn and the nitrogen, calcium, magnesium and sulphur concentrations in Congo grass. Excess nitrogen promoted reduction of the phosphorus in the Corn-Congo grass intercropping system in the dry season.