伊勒呼里山南麓主要树种心腐的外部特征及延伸程度的判断

本文就大兴安岭地区的若干树种进行心腐的外部特征及延伸程度的总结和分析,认为:兴安落叶松心腐的外部特征是外表有破损或破损痕迹,树皮干枯,树干凸凹不平,有鼓包,心腐一般延伸距鼓包1.5—2m。白桦:①萌生林的心腐由老树墩引起,有条件时腐朽会蔓延;②活立木的心腐多数在根部,其延伸程度有规律;③实生林的心腐只有在枯立木、冻裂的活立木上发生。杨树:①甜杨心腐发生在少数过熟林的根部,延伸1—3m;②山杨心腐的外部特征是有乳头状的鼓包,材身表面有菌,根部心腐一般延伸2—3m,树干心腐面积小,延伸长。     

小麦慢白粉抗病性的组分和影响因素研究进展

自1970年发现小麦品种Knox对白粉病(Blumeria graminis f.sp.tritici)的抗性以来,小麦慢白粉抗病性为抗性材料的利用和品种选育提供了一个有意义的发展方向。本文对小麦慢白粉抗病性的组分和外界环境引起的慢白粉性的改变作了较为详尽的讨论，指出侵染效能和产孢能力的降低是小麦慢白粉抗病性的基本组分，小麦生育期和慢白粉抗病性的表达密切相关，N肥施用量以及播期对病害的影响在抗性程度不同的慢白粉品种上不尽一致。文中还提出今后需要明确和解决的问题，以期充分利用和保存这一具有持久特性的抗病资源。     

论图书馆核心竞争力的外部构建

以分析图书馆核心竞争力内涵为基础,从外部构建的角度,针对如何提高图书馆核心竞争力,提出并详细分析了转变信息服务模式、图书馆战略联盟、图书馆部分业务外包、加强图书馆危机管理等策略。     

浅谈计算机视觉技术在果蔬外观品质检测中的应用

果蔬的外观品质是评估其市场价值、被消费者选择的依据之一,而且在某种程度上也会影响它们的内部品质。本文分析了计算机视觉系统对果蔬外部品质检测的发展现状,提出了计算机视觉技术在南疆果蔬外观品质检测中存在的问题及建议,旨在为新疆南疆地区水果和蔬菜品质检测技术的研究和发展提供参考。     

两个层面——风景园林规划设计中的艺术语言研究

在分析风景园林规划设计中艺术语言的两个层面-潜性艺术语言和表性艺术语言后，提出了园林规划设计作为造型艺术作品的一种形式，受到了艺术语言制约的观点，丰富了设计师在造园实践中的艺术语言，强调了营造高格调的优秀园林，依赖于设计师对园林艺术语言的整体表达和娴熟运用。     

Effect of the application of the leaf mulch of Gliricidia sepium on early development,leaf nutrient contents and tuber yields of water yam (Dioscorea alata)

This paper describes the effects of the leaf mulch of Gliricidia sepium on the development and yield of Water Yam, Dioscorea alata. Using leaf mulch, the time taken for the yam setts to sprout can be shortened by approximately 20 percent.Organic mulches contain considerable quantities of plant nutrients. Increasing amounts of mulch improved the leaf nutrient contents of the yam crop and resulted in significantly higher tuber yields. Over a tuber yield range up to c. 15 tons ha^–1 each additional ton DM Gliricidia sepium mulch applied resulted in a yield increment of about 2 ton yam tubers. A nutrient supply — nutrient extraction balance is discussed, comparing mulch applied and yam tubers harvested.Mulching as agricultural technique is a useful and affordable tool in adapting low external input cropping systems to local economic and environmental conditions.     

The role of the external mycelium in early colonization for three arbuscular mycorrhizal fungal species with different colonization strategies

Arbuscular mycorrhizal fungi (AMF) differ in their rate and extent of colonization of both plant roots and soil but the mechanism responsible for these differences is unclear. We compared the external mycelium of three AMF isolates (Glomus intraradices, Glomus etunicatum and Gigaspora gigantea) during early colonization of plant roots. We investigated whether an AMF with the most rapid colonization would have higher numbers of infective structures (i.e., infection hyphae and contact points), an AMF with extensive root colonization would have more infection units, and (3) AMF with extensive soil colonization would have large numbers of all external features (including absorptive hyphae, runner hyphae and hyphal bridges). Using specially designed soil and root observation chambers, we followed the development of the external mycelium for 7 weeks. We found that rapid colonization rate was due, in part, to the presence of more infective structures, in particular more infection hyphae and root contact points. Second, the extensive root colonizer had more, larger infection units. Third, data did not support the hypothesis that the extensive soil colonizer had more external structures. These results show that differences in the architecture of the external mycelium are responsible, in part, for variation in the colonization strategy of AMF.     

外源氮素对叶菜硝酸盐含量影响的研究

蔬菜增施N素营养,有利于产量的提高,但同时也增加了硝酸盐在蔬菜体内的积累;蔬菜种类不同,硝酸盐的转化与累积是不同的,即使在蔬菜停止生长之时,体内硝酸盐也在发生着变化。     

黄晶果花芽形态分化研究

【目的】通过探究黄晶果花芽分化进程,了解花芽分化的特性,为花期调控技术提供理论依据,进而完善产期调控技术。【方法】以漳州市农业科学研究所资源圃中种植的黄晶果为材料,采用田间观察和石蜡切片相结合的方法,对其花芽分化过程的组织形态结构进行观察和对比分析。【结果】黄晶果于4月1—6日花芽开始进入形态分化初期,芽体生长点分生组织分裂加快,顶端呈圆锥形;4月6—11日为萼片分化期,由于花芽内、外层细胞分裂速率不同从而使周围形成突起,形成花萼原基;4月11—16日为花瓣分化期,在花萼原基的内侧,花原基边缘部位出现新的突起形成花瓣原基;4月16—21日为雌雄蕊分化期,内部花瓣原基继续生长发育,萼片和花瓣逐渐伸长,生长点持续变宽,在花瓣原基内侧分化出数个小的凸起,从而形成雄蕊原基,同时花芽体内部中间位置分化出1个新的凸起,即雌蕊原基形成;4月21—26日为子房膨大期,雌蕊原基下部逐渐膨大形成子房,子房内部出现胚珠原基,同时加速生长,顶部形成明显的突出;4月26日—5月1日为雌雄蕊成熟期,子房持续膨大呈葫芦形,子房内1～2个胚珠,花药已全部形成,花芽形态分化完成,黄晶果花各个器官逐渐发育成熟。【结论】黄...