早熟薹蒜无公害标准化栽培技术探讨

从介绍温、光、水、肥等因子对薹蒜生长发育的影响出发,阐述了早熟薹蒜无公害标准化栽培技术,包括栽培方式、合理密植、产地环境、化学投入品的限制等方面,为实现薹蒜无公害早熟生产,达到高产、质优、增效的目的提供了参考。     

橡胶树萌动芽种植材料定植季节最优选择的理论研究

测定橡胶树不同季节萌动芽的持水力及几种渗透活性物质,并以此判断最适宜的定植季节。结果表明:1.不同季节萌动的芽,其持水力不同,主要的原因是不同季节萌动芽所含渗透活性物质的“量”不等。2.直接参与萌动芽持水力变化的渗透活性物质有无机离子和有机溶质。有机的渗透活性物质主要是可溶性糖和游离氨基酸。3.脯氨酸含量与萌动芽的持水力不表现协同关系,表明细胞胶体亲水性的强弱,不是持水力变化的主要因素。4.萌动芽的持水力以2、3月为最强,次为5月中旬以后,4月中、下旬为最弱。结合气候条件来考虑,最优定植季节应在2、3月间。如在早春干旱地区,宜挖苗装袋后,延至雨季来临,带两莲叶全苗定植为最佳。4月不宜大田定植或装袋培育后再定植。5月中已开始进入小雨季,采用露根定植萌动芽种植材料即可。     

工厂化豆芽成为现代加工食品新宠

伴随着经济、社会特别是科学技术的发展,我国传统家庭作坊式的豆芽生产已被日产60～100t的程序化、机械化、自动化、可调控的现代工厂化生产方式所取代。论述了我国工厂化豆芽产业的发展现状、加工特点、卫生安全、生产规范与市场监管机制,探讨了我国豆芽工厂化生产的可持续发展趋势,以期提升中国芽菜形象,改善人民生活质量,提升国际竞争力。     

花椒芽菜栽培技术与病虫害防治

花椒芽菜属于体芽菜,即采摘花椒树上的幼嫩枝、叶和芽为菜,具有独特的风味,且营养极其丰富,备受人们的青睐和喜爱。近年来,在花椒芽菜日光温室栽培的基础上,深入研究了露地网棚囤栽培技术,取得了明显效果,为平顺县大力发展经济作物提供了新技术。     

沙棘平茬复壮更新技术研究

通过对沙棘林不同龄组、不同季节平茬复壮效果的研究表明:沙棘林栽植后5～7a进行平茬更新效果最佳,萌蘖株数达到3.89万株/hm2,幼树生长旺盛,在平茬时间上以春季平茬效果最佳。沙棘根部萌蘖的苗木生长格外旺盛,雨季平茬效果欠佳。     

柚木小棒槌苗贮藏技术的研究

柚木小棒槌苗的贮藏,由Hocking和Nyland(1971)开始研究。1985-1987年,我们进行了沙池贮藏,取得贮藏期达5个月,包装运输21天或贮藏期达15个月,造林成活率达90-100％,贮藏期18个月和19个月,造林成活率75-90％的结果。而泰国的试验结果为:贮藏5个月,造林成活率76-87％;贮藏9个月,造林成活率57％(A.Kaosa-ard,1977)。这一技术与传统切干苗比较,不仅降低了造林成本,而且成活率更高和生长更好;还为集中育苗分散造林提供一重要手段;有利于高集约现代化经营管理和良种的繁育;解决了“抢雨造林”与“突击起苗”的劳力矛盾及纬度较高地区柚木苗的越冬防寒问题。     

Effects of Light Intensity and Regeneration Mode on Stem Form and Growth of Cunninghamia lanceolata Saplings

ABSTRACT

Regeneration plays an essential role in the restructuring of plant communities, with seedlings and sprouts representing two different regeneration strategies. As an important timber species, Cunninghamia lanceolata is widely distributed throughout southern and eastern China. However, the morphology and growth of its sprouts and seedlings under natural environments have not been examined in detail. Our study quantified the morphology and growth of Cunninghamia lanceolata during its early regeneration phase. We selected a secondary mixed coniferous forest in the Huangshan region of China as the research location, and examined sapling height, basal stem diameter, lateral branch length, as well as the relationships between main stem and lateral branch elongation, and between sapling basal stem diameter and height. The results showed that high light intensity promoted the extension growth of main stems and the elongation of lateral branches of seedlings. Meanwhile, sprouts generally had shorter height growth than seedlings with the same basal stem diameter, and the growth allocation of seedlings was generally more dependent on light intensity. Our findings suggest that the morphology and growth of C. lanceolata might vary depending on the interaction of regeneration mode (plants originating from sprouts or seedlings) and light intensity.     

山西灵空山林区辽东栎萌芽更新规律研究

以灵空山林区典型辽东栎皆伐迹地为研究区,调查了辽东栎伐桩径、高以及萌枝的数量、高度、基径等指标,分析了辽东栎萌芽更新规律。结果表明,在一定范围内,萌芽数量随着伐桩径的增大呈现先增多后减少的规律;而伐桩高与萌芽数量呈现弱相关,萌芽数量大体随着伐桩高的增大而增多,随即产生急剧下降的趋势。但萌枝的平均高、平均基径却不随伐桩径、高的变化而变化。在伐桩径、高的双因素方差分析中发现,对于辽东栎伐桩内萌芽数量而言,伐桩径与伐桩高具有显著的交互作用,而且伐桩高因素(5~20cm与21~40cm范围)具显著差异。     

Collembola in low stumps at clear-cuts. Is stump harvesting a threat?

Abstract

Stump harvesting as a way to increase wood biomass production in order to meet the European Union targets for reduced CO₂ emissions is starting up in Sweden. The knowledge about if and how Collembola species can use low stumps as a substrate is very limited. Stumps of three different ages (4, 14 and 75 years) were sampled to see if Collembola used the dead wood during the whole rotation period of a forest. Stumps of spruce, pine and birch were compared. Both the bark and the splint wood of the stumps were sampled. To determine whether the stump also influenced the nearby soil, the soil close to the stump were sampled as well as the soil further away. In total, five Collembola species that are known to prefer dead wood as a substrate were found in the stumps. Wood specialists were more dominating in young stumps, but occurred also in the oldest stumps. No preference was found for any specific tree species. Wood-living Collembola seem to be able to survive in low stumps for a whole rotation period, at least in low numbers. There is, however, a risk for extinction debt due to their low capacity for active long-distance dispersal.     

Effects of various stress treatments on growth and ethylene evolution in seedlings and sprouts of betula pendula Roth and B. pubescens Ehrh.

Experiments were conducted to determine growth and ethylene evolution in seedlings and coppiced plants of Betula pendula Roth and B. pubescens Ehrh. when subjected to stresses relevant to the maintenance of natural forests, and especially in fuelwood plantations, i.e. cutting of the stem, thinning, bending, flooding and various combinations of these. Most of the experiments were carried out in the laboratory using 1‐year‐old seedlings or 1‐month‐old sprouts. Height and diameter growth, biomass production, morphology and ethylene evolution were studied for 1–2 months. Material for comparison was obtained from young sprouts on the stumps of fully developed trees growing under natural conditions and natural seedlings of a comparable age. Exposure of seedlings and coppiced plants to stress factors usually altered growth and increased ethylene evolution. Cutting of the stem and thinning had similar effects in that they stimulated transient ethylene evolution by both roots and stems. Bending retarded the height growth to some extent, while increasing the ethylene content especially on the lower side of the horizontal stem. Flooding arrested height growth and increased ethylene evolution in the roots. The two species reacted basically in similar ways, but B. pendula produced more ethylene. though at a slower rate, and also showed a more pronounced retardation of growth. The sprouts had a higher ethylene content than the seedlings and also increased their ethylene evolution more rapidly. The changes in ethylene evolution and growth are discussed from the point of view of the resilience of the plants and as an indication of stress factors in experimental plots.