控释尿素对鸭梨的肥效研究

设不施氮、施普通尿素、施控释尿素80％、施控释尿素60％4个处理,研究控释尿素对鸭梨产量、品质和土壤氮素的影响.结果表明:与100％普通尿素比较,控释尿素的用氮量为普通尿素的80％,0～30 cm土壤的碱解氮与硝态氮的含量及梨果的产量显著增加.用氮量60％,与普通尿素的接近.控释尿素处理的梨果品质、氮肥利用率显著提高,且以用氮量60％的肥效最佳.     

控释氮肥及减氮对设施番茄产量及土壤呼吸的影响

以"佳美8号"番茄为试材,设置5个处理分别为CK(不施氮肥)、U处理(普通尿素配施水溶肥)、CRU处理(控释氮肥配施水溶肥)、-20％CRU处理(控释氮肥减氮20％配施水溶肥)、-40％CRU处理(控释氮肥减氮40％配施水溶肥),采用LI-8100A碳通量测量系统对设施番茄土壤呼吸进行测定,研究了控释氮肥及减氮对设施菜田土壤呼吸的影响,以期为控释氮肥减量施用增加番茄产量降低土壤呼吸速率提供参考依据.结果 表明:番茄生长季各处理土壤呼吸速率峰值均出现在定植后的10～15 d和追肥后的5d,控释氮肥及减氮处理均降低了土壤呼吸速率峰值,且随着生育期的延长土壤呼吸速率峰值呈逐渐降低趋势.土壤碳累积排放量呈现为U＞CRU＞-20％ CRU＞-40％ CRU＞ CK,与U处理相比,CRU、-20％CRU和-40％CRU处理土壤碳累积排放量分别降低了21.88％、27.54％和31.51％.CRU和-20％ CRU处理较U处理产量分别提高了10.57％和8.14％.相关分析结果表明土壤湿度、铵态氮(NH+-N)、硝态氮(NO3-N)、pH与土壤呼吸速率存在极显著相关性,微生物量碳和氮、纤维二糖水解酶、β-1,4-木糖苷酶、β-1,4-N-乙酰基氨基葡萄和α-葡糖苷酶与土壤呼吸存在极显著或显著相关性.     

控释氮肥对菜薹(菜心)产量和品质的影响

通过田间试验研究了等氮量的4种不同包膜材料的控释氮肥对菜薹(菜心)产量和品质的影响。结果表明,控释氮肥能显著提高菜心产量和品质,与同期施用等氮量普通尿素相比,施用控释氮肥可使菜心产量提高19.1%～28.2%;其中PDU处理的效果最好,不但产量最高,而且VC和可溶性蛋白质含量也最高,硝酸盐含量最低。     

不同用量控释氮肥在葡萄生产上的施用效果

以速效氮肥分次施用的习惯施肥方式为对照,设置不同用量的包膜尿素和等量普通尿素一次性施用处理,研究不同用量控释氮肥对葡萄生育性状、产量和可溶性糖的影响。结果表明:施用控释肥对葡萄穗重、穗粒数、粒重等指标有一定影响,与习惯施肥处理相比,葡萄的可溶性糖有了明显提高。从产量结果看,施用一定量控释氮肥和速效氮肥一次性施用,与习惯施肥产量持平或显著提高,同时减少了氮素养分投入量和施用次数。综合来看,在当地试验条件下,以每667m2施氮24kg,其中控释氮14kg,速效氮10kg,做基肥一次施用的方式效果最好。     

控释尿素对鸭梨产量和氮素利用率的影响

采用小区试验,以鸭梨为试验材料,施用普通尿素100%、控释尿素80%、控释尿素60%,研究控释尿素对鸭梨产量、梨果品质和土壤氮素利用率的影响。结果表明:施用控释尿素80%与施用普通尿素相比,土壤耕作层(地表0～30cm)的碱解氮与硝态氮含量、鸭梨产量均显著增加;施用控释尿素60%与施用普通尿素鸭梨产量相近,但梨果品质、氮素利用率明显提高。在考虑肥料、产量、收益等综合指标的情况下,施用控释尿素比普通尿素多收益325.31元/hm2。     

不同氮肥处理对无核黄皮秋梢生长和果实产量及品质的影响

以无核黄皮为试材,研究了不同形态氮肥作为壮梢肥和促花壮果肥,对其秋梢生长、果实产量及品质的影响.结果表明:4种氮肥处理中施用酰胺态氮+铵态氮(尿素和硫铵各占氮源50％)的处理在满足秋梢生长中表现最优;无核黄皮结果果实产量均以施氮品种为酰胺态氮+铵态氮处理为最高;果实的可溶性固形物、可溶性糖含量、酸度在4个不同氮源的氮肥处理之间均没有显著性差异;但是无论在海日园还是波波园中酰胺态氮+铵态氮配施处理维生素C含量最高.在施用氮含量相同下,酰胺态氮与铵态氮配合制成的无核黄皮专用肥能够促进其秋梢生长发育,提高果实产量和改善品质.     

控释氮肥对温室番茄增产效应及利用率的研究

利用田间试验 ,对控释氮肥与尿素影响温室番茄产量、生长、叶片含氮量及氮素利用率进行研究。试验结果表明 :在日光温室栽培条件下 ,控释肥能够明显提高番茄的产量。在等氮量 (6 0 0kg/hm2 (公斤/公顷 ) )前提下 ,控释尿素处理的产量比尿素多 34.35t/hm2 (吨 /公顷 ) ,增产率也提高 2 4 .5 5个百分点。甚至在施氮量减半的情况下 ,控释尿素处理的产量和增产率仍比尿素高。试验结果还表明 :与尿素相比 ,控释尿素在番茄生育的中后期能明显提高叶片中氮素含量 ,从而表明控释尿素的养分释放 ,可满足番茄全生育期对氮素的需要。同时 ,控释尿素也能提高总生物量和叶片干物量。从氮素利用率来看 ,控释素为 37.91%～5 9.98% ,而尿素利用率只有 10 .92 %～ 16 .0 6 %。在等施肥量的情况下 ,不考虑施肥方式等其它因素 ,控释肥的当季利用率是尿素 2 .4倍。     

控释氮肥对土壤和苹果树氮含量及苹果产量的影响

采用浸水释放试验和苹果田间试验研究了有机高分子聚合物包膜控释氮肥的释放特征, 并以普通尿素为对照, 研究了包膜控释氮肥对苹果产量、品质的影响。浸水试验结果表明, 控释氮肥的释放分为逐渐增大、释放高峰、逐渐减小3个阶段; 田间试验结果表明, 与普通尿素相比, 控释肥的氮素释放模式与苹果树对氮素的需求相一致, 增加了叶片叶绿素、叶片和枝条中氮素的含量, 提高了果实产量、糖、钙、维生素C含量, 降低了氮含量。     

冀西北坝上旱地大白萝卜缓释氮肥效应研究

以冀西北坝上旱薄沙土-作物系统为研究对象,通过对萝卜产量、氮素利用率、硝酸盐含量及其经济效益的分析,研究了自制缓释氮肥在该区域的应用效果.结果表明:氮素利用率随着施氮量的增加而逐渐降低,但缓释氮肥的氮素利用率较等氮量下的普通尿素提高了4％～11％.与施用等氮量尿素处理相比,缓释氮肥明显提高了萝卜产量,其增产范围在1.98％～8.19％,净收入增幅在0.97％～7.69％.萝卜体内硝酸盐含量与施氮量呈极显著正相关.由此可见,在冀西北坝上旱薄沙地上,缓释氮肥在提高土壤氮素利用率、增加萝卜产量、降低萝卜体内硝酸盐累积和提高经济收益方面具有明显的促进效应.     

控释氮肥对苹果生长影响及经济效益分析

采用静水释放试验和田间试验方法,研究了有机高分子聚合物包膜控释氮肥的释放特征,并以普通氮肥作对照,研究了包膜控释氮肥对苹果的生长及经济效益的影响.控释肥静水释放试验表明:控释氮素的释放速率分为逐渐增大、释放高峰、逐渐减小3个阶段.大田试验表明:与普通氮肥相比,控释氮肥在苹果整个生长周期内持续的释放养分;在施氮量减少一半的情况下,施用控释氮肥0.458 kg/株比施用普通尿素0.87 kg/株果实产量和经济效益分别提高了30.08%、30%;控释氮肥提高了果实糖、钙、维生素C含量,降低了氮含量.     

Sweet-potato productivity as affected by recurrent use of vines as planting-material

Yield performances of apical shoot cuttings of sweet potato (Ipomoea batatas) obtained from crops raised 2 or 4 times recurrently through vines, were compared with those obtained from tubers. The recurrent use of vines as planting-material did not show any marked variation in market-grade tuber yield, but it significantly decreased vine yield and increased weevil infestation in tubers. Cultivars ‘Cross-4’, ‘RS-5’ differed significantly in performance     

Progress in resistin and type 2 diabetes as well as obesity

Resistin, a new hormone found in the year 2001 and secreted by adipocytes, is related to type 2 diabetes and obesity. It brings some hope to solve the medical hamper of insulin resistance. The resistin discovery, molecule structure, function and expression, secretion regulation as well as gene polymorphism are reviewed in the article.     

番茄叶黄素合成突变与光能分配和抗氧化酶活性的关系

以叶黄素（Lutein）缺失的番茄突变体（Xa）为材料,研究其光合和叶绿素荧光特性、吸收光能分配、细胞器水平抗氧化酶活性及抗氧化物质含量。结果表明：Xa突变体的非光化学猝灭系数（qN）、叶片吸收光能分配依赖于△pH和叶黄素的非结构性热耗散（J_NPQ）显著低于其野生型Ailsa Craig,但净光合速率（Pn）、羧化效率（CE）、光化学猝灭系数（qP）与Ailsa Craig相似。此外,Xa突变体叶片细胞器水平的抗氧化酶活性和抗氧化物质含量大多数显著高于Ailsa Craig。这些结果表明,叶黄素缺失体主要通过降低光能吸收和提高抗氧化能力来避免过剩光能导致光氧化胁迫的产生。     

百合鳞茎苯丙氨酸解氨酶的分离纯化及酶学性质研究

经40 %～75 %硫酸铵分级沉淀和DEAE-Sepharose离子交换层析,从兰州百合（Lilium davidii var. unicolor）鳞茎中分离纯化苯丙氨酸解氨酶（PAL）,纯化倍数为13.19,酶回收率4.68%。纯化的PAL经 SDS-聚丙烯酰胺凝胶电泳（SDS-PAGE）检测为单一蛋白带,其亚基分子量约58.7 kD。酶学性质研究表明：百合鳞茎的PAL不耐碱,更不耐酸;随着水浴时间延长和水浴温度提高,PAL活性逐渐降低,但40 ℃水浴30 min后酶活性仍保留47%;以L-苯丙氨酸为底物,40 ℃下的Km值为4.1×10^-3 mol·L^-1;金属离子Mn²⁺、Fe²⁺、Cu²⁺、Fe³⁺促进PAL活性,1.0、1.0、2.0和1.0 mmol·L^-1分别为在供试范围内的最佳处理浓度,Ag⁺、Co²⁺、Ca²⁺抑制其活性,其中Ag+的抑制作用最强。     

Positioning aesthetic landscape as economy

Flexibility is required in modern times to comprehend vast and fluctuating levelscapes of information. The ability to observe, simulate, and assimilate situations and circumstances from different points of reference and view is paramount for survival. This ability as preamble to consequence in landscape is valid, and provides an impetus for expanding landscape ecology from its traditional realm of definitive terrafirma to an assimilation of terraform (i.e. the process that alters an environment capable of supporting life forms). The traditional human-nature duplexity, regarding landscape ecology, is simulated with real and virtual fields in a noöspheric configuration. The involvement of culture (i.e. by consensus of value) and history (i.e. by sequencing relevancy) is a contributing determinant of “real” (landscape_r) and “virtual” (landscape_v) fields of existence and extinction. Within this noöspheric network unique observations of landscape ecology are possible (e.g. eco-field). Suggested in the noöspheric network, aesthetics is an efficiency relevant to life-support systems exemplified by value that precludes aestheticism (i.e. typically limited to a dichotomy of beautiful and ugly). Aesthetics viewed as a transcending process through levels of ecological organization and as a transcending property of transcending processes becomes understood as economy (energetic efficiency) capable of supporting nonmarket and market units of valuation. The consequence of these units of valuation articulates as subjects or objects of criticism within an aesthetic set point model, which measures individual or societal tolerance.     

Relationship between genetic polymorphisms of GSTM1 as well as GSTT1 and lung cancer

AIM and METHODS:To examine the relationship of glutathione S-transferase M1(GSTM1) and T1(GSTT1) with the occurrence of lung cancer, The case-control study was conducted among 161 lung cancer and 165 healthy controls. The genetic polymorphisms of GSTM1 and GSTT1 were detected with the method of multiplex polymerase chain reaction. Logistic regression analyses were used to assess the interaction of between different genotypes as well as between null genotypes and smoking. RESULTS:The frequences of GSTM1 and GSTT1 null genotypes had no obvious difference between lung cancer and healthy controls. In non-smoking subjects, the frequence of GSTM1 null genotype was significantly different between lung cancer and healthy controls. Furthermore, GSTM1 null genotype was significantly overrepresented in adenocarcinoma patients aged 60 or over, compared with controls.The results from interaction analyses showed although smoking and GSTM1 deletion were associated with an increased risk of lung cancer, GSTM1 and GSTT1 null genotypes combined with smoking did not have interaction effect on the risk of lung cancer. The risk for adnocarcinoma in the individuals at the age of 60 or over and in nonsmokers without GSTM1 gene but with GSTT1 functional genotype decreased by 48.5% and 45.3%, respectively. CONCLUSION:Our results suggest that GSTM1 deletion is an important host risk for lung cancer, and imply that GSTT1 functional genotype protects the old (aged 60 or over) and nonsmokers who are lack of GSTM1 gene from the risk of adenocarcinoma.     

大叶芥菜作为植物熏蒸材料与主栽作物番茄间作模式探索

以大叶芥菜为主要的植物熏蒸材料,通过改变其与主栽作物番茄间作的不同种植模式,分析大叶芥菜产量、大叶芥菜硫代葡萄糖苷含量、番茄根结指数、番茄产量等指标,探索生物熏蒸效果佳、作物产量高、可以大面积推广的间作模式。结果表明:间作模式1(栽培大叶芥菜前将番茄吊蔓的2架钢丝距离调整为50~60 cm,第1茬番茄拉秧后将棚内温度调高2~5 ℃)效果最好,大叶芥菜的产量、硫代葡萄糖苷含量最高,根结线虫抑制效果最好,同时每667 m^2番茄产量最高,达12 216.5 kg,可大面积推广。     

Disturbance has benefits as well as costs for fragmented populations of a cryptic grassland reptile

Landscape Ecology - Conservation practitioners face complex decisions about the management of spatial and temporal disturbance regimes when disturbance plays a significant role in the dynamics of...     

Forest fragmentation as an economic indicator

Despite concern over the ecological consequences of conversion of land from natural cover to anthropogenic uses, there are few studies that show a quantitative relationship between fragmentation and economic factors. For the southside economic region of Virginia, we generated a surface (map) of urbanization pressure by interpolation of population from a ring of cities surrounding the region. The interpolated map showed a geographic gradient of urbanization pressure or demand for land that increased from northwest to southeast. Estimates of forest fragmentation were moderately correlated with the geographic gradient of urbanization pressure. The fragmentation-urbanization relationship was corroborated by examining land-cover change against the urbanization map. The geographic gradient in land-cover change was strongly correlated with the urbanization pressure gradient. The correspondence between geographic gradients in land-cover change and urbanization pressure suggests that forest fragmentation will occur at a greater rate in the eastern portion of the southside economic region in the future.     

Carbaryl as a Fruit Thinning Agent

The results are presented of fruit thinning studies carried out over several years with the apple varieties Laxton’s Superb and Worcester Pearmain.

The thinning activity of carbaryl was negligible at 0·0028% a.i. but increased rapidly over the range 0·0083% to 0·075%. Comparatively little additional thinning resulted from a further increase in concentration.

In Worcester Pearmain thinning was stimulated by applications of carbaryl over a 4–5 week period from petal fall, the cessation of thinning activity coinciding with the end of the main period of natural fruitlet shedding. The intensity of thinning was greatest at petal fall and declined with delay in application. This decline was not continuous but showed two intervals of 7 to 13 days duration during which the intensity of thinning remained relatively constant. Up to 12 days elapsed between application and the commencement of induced fruitlet shedding.

Carbaryl was found to thin within, rather than between, fruitlet clusters, and to stimulate the abscission of lateral fruitlets more than terminal ones.

The growth of young fruitlets was retarded for a short period following the application of carbaryl, but as a result of thinning the size of mature fruit was increased. In the year after treatment increased blossoming and cropping was most marked with biennial trees of Laxton’s Superb. With regularly cropping trees of Worcester Pearmain, although thinning induced a moderate increase in subsequent blossoming, no residual effects on cropping were detected.