木醋液对帝王花种子萌发的影响

对帝王花种子吸水特性和种子活力进行测定,发现种子本身状况良好,种皮不是限制萌发的主要因素;用100倍、800倍、1500倍3种浓度的木醋液浸种处理48 h,研究对其发芽率的影响,结果表明,稀释800倍的木醋液效果最好,其发芽率、发芽势和发芽指数均高于对照组.     

Unusual External Adaptations in the Rock Hyrax

Activity in two unrelated genera of mole-rats, Tachyoryetes and Heliophobius, was studied in the field by recording the movements of animals tagged with radioactive wire. Tachyoryetes shows a single marked activity peak and only leaves its nest between 10.00 and 19.00 hour. Heliophobius shows a more dispersed and prolonged activity pattern although peak activity occurs over approximately the same period as in Tachyoryetes. Heliophobius spends over 50 of the day out of its nest, Tachyoryetes, under 25%.

These differences can be attributed to a different function of the nest in the two genera (Tachyoryetes has a multipurpose nest; Heliophobius uses its nest solely for rest), and also to the fact that Tachyoryetes has light-sensitive eyes whereas Heliophobius appears unable to appreciate light; Tachyoryetes periodically comes to the surface to forage and this exposure to light may trigger the 24-hour activity cycle.     

Reducing oxidative browning during in vitro establishment of Protea cynaroides

Oxidative browning is one of the reasons why Protea cynaroides is not being extensively propagated via tissue culture techniques. The reduction of oxidative browning was best achieved by stirring the explants for 1 h in an antioxidant solution mixture containing 100 mg l⁻¹ ascorbic acid and 1500 mg l⁻¹ citric acid before inserting them into the medium. In combination with this antioxidant solution, in vitro establishment was highly successful where 100% bud growth was achieved by explants growing under 16 h photoperiod.     

Nutrient Removal,Fertilization Needs and Yields of Protea Plants Cultivated in Subtropical Conditions

A study of nutrient removal was carried out in commercial protea plantations of each of the cultivars ‘Scarlett Ribbon,’ ‘High Gold,’ ‘Veldfire,’ and ‘Sunrise’ of Leucospermum cordifolium, and of the species L. patersonii,located in a subtropical region (La Palma, Canarian Archipelago).

Flowering stems of optimal commercial quality were taken from each of the mentioned cultivars and species, once a year (2003 and 2004) at harvest time (January to April), and the different organs were analyzed separately. Flowering stems of the cultivars ‘High Gold’ and ‘Veldfire’ presented the highest contents of most studied nutrients, whereas the opposite was observed in ‘Scarlett Ribbon’ and L. patersonii. Mean yields of flowering stems varied very much among cultivars, and the highest ones were those of ‘High Gold’ and ‘Scarlett Ribbon’. The cultivar ‘High Gold’ removed the highest quantities of studied nutrients, and the contrary was observed in L. patersonii for most of them.

Suitable rates of nitrogen (N): phosphorus (P): potassium (K) fertilizers for nutrient restitution purposes were 1:0.08:0.40 for ‘Scarlett Ribbon,’ 1:0.08:0.66 for ‘High Gold,’ 1:0.08:0.38 for ‘Veldfire,’ 1:0.09:0.75 for L. patersonii;and 1:0.18:1.11 for ‘Sunrise’.     

土壤干旱和盐胁迫对帕洛特王幼苗生长及生理特性的影响

以山龙眼科木本切花植物帕洛特王1 a生扦插苗为材料,研究其对土壤干旱和盐胁迫的生长、形态及生理生化反应的影响.结果表明:干旱及盐胁迫对帕洛特王幼苗的生长及各器官的生物量积累无显著影响.干旱条件下,根/冠比显著增加,说明该植物可以通过地上地下生物量的分配来积极地适应干旱.盐胁迫下,帕洛特王幼苗叶片相对含水量显著下降,叶绿素a含量显著上升,抗氧化酶活性及可溶性渗透调节物质也显著增加,说明该植物可通过一系列生理生化特性的改变来积极抵抗盐胁迫.在该研究中,干旱处理及盐处理对帕洛特王植株影响较小,说明帕洛特王对于土壤干旱及盐分具有一定的耐受性.     

皇后帝王花种皮特性对种子休眠的影响

以皇后帝王花种子为实验材料,对其进行形态解剖、种皮超微结构观测、种皮透水性与含水量检测,以了解皇后帝王花种皮结构与种子休眠的关系。结果表明:(1)皇后帝王花种子的种皮分为3层,外种皮的栅栏结构增强了种子的不透性,高度木质化的中种皮使种子坚硬,内种皮较薄却被一层不易透水的蜡质包裹;(2)酸蚀处理能使皇后帝王花种子种皮表面结构疏松,种皮变薄,种孔露出。但酸蚀4 h种子的中种皮及内种皮已经出现破坏性开裂,严重影响到胚活力;(3)完整干种子与酸蚀0.5 h种子在前14 h均能快速吸水,吸水50 h后近饱和状态,自此,二者吸水率小范围波动直至完全饱和;(4)酸蚀处理种子并不能使胚更好的吸水保水。因此,皇后帝王花种皮结构对胚的吸水并未形成阻碍,但不能排除其对胚呼吸的影响及对胚根的伸长和生长产生机械阻力的可能。     

Variation in nutrition along time and relative chlorophyll content of Leucospermum cordifolium cv. ‘High Gold’, and their relationship with chlorotic sypmptoms

Foliar samples, SPAD-502 measurements (both along the growing season), and soil samples were taken from protea plants (Leucospermum cordifolium), cultivar ‘High Gold’ cultivated in six commercial plantations of La Palma Island (Canarian Archipelago). Soil data (pH, available P, Ca, Mg, K and Na, and EC) ranged within normal levels for proteas, though O.M. was high. Drainage decreased the potential problem that could be caused by the high clay content of the soils. Leaves showed high concentrations of N, K, Mg, and Na, while Ca and Cu were normal. On the other hand, Fe and Zn presented some low foliar levels, while Mn values fluctuated depending upon the different plantations. N contents were higher in spring, and those of K, Ca, Mg, and Na increased with time. Relative chlorophyll contents (SPAD-502 measurements) were compared with macro- (N, P, Na, K, Ca, Mg) and micro- (Cu, Fe, Mn, Zn) foliar levels. Results showed no positive correlation between leaf chlorophyll and N content. Higher leaf N concentrations were observed in chlorophyll deficient than chlorophyll sufficient leaves at one site and vice versa at another site. In contrast, lower Mn, Fe and Ca concentrations, the last corresponding with higher ratios of N/Ca were observed in chlorophyll deficient than chlorophyll sufficient leaves at several sites. It is concluded that amendment of soils with Mn, Fe and Ca may prevent the development of chlorophyll deficiency symptoms, associated with diminished photosynthetic capacity, in this important commercial cultivar.     

皇后帝王花种子休眠及解除方法研究

皇后帝王花（Protea magnifica）种子具有休眠性,不经任何处理难以发芽。本研究以皇后帝王花种子为试验材料,通过测定皇后帝王花种子生活力、种子萌发率、种子各部分粗提液对白菜种子发芽的影响,并以不同的方式（短时高温+变温层积、酸蚀处理+变温层积、赤霉素处理+变温层积）处理种子,研究皇后帝王花种子的休眠原因及解除方法。结果表明：试验所用皇后帝王花种子的生活力高达90.00%,但不去除种皮的完整种子30 d内不发芽。种皮粗提液不仅抑制白菜种子的发芽,还显著影响白菜种子的根与地上部分的生长。皇后帝王花种子的休眠可能是种皮的机械障碍和种皮的内源抑制物共同引起的综合休眠。时长为2 min的不同高温（40~120 ℃）处理+变温层积、不同时间（10~ 70 min）的98%浓硫酸酸蚀处理+变温层积、不同浓度（0.3、0.5、0.7 mg/L）的赤霉素溶液处理+变温层积都可以打破种子的休眠,提高皇后帝王花种子发芽率和发芽势。其中各处理分别以60 ℃的短时高温处理、30 min的酸蚀处理、0.7 mg/L的赤霉素溶液处理效果最好。综合比较,30 min的酸蚀处理为解除皇后帝王花种子休眠的最佳方法。此外,赤霉素处理对皇后帝王花种子的休眠解除有着一定的促进作用,但相比其他两种处理方式效果并不理想。     

不同预处理对2种山龙眼科种子出苗率的影响

采用播种前对种子进行不同浸种处理和低温恒温层积处理的方法,研究不同预处理对美极山龙眼(Protea eximia)、大叶山龙眼(Protea magnifica)出苗率的影响。结果表明,播种前对美极山龙眼种子采用4 g.L-1的烟丝水浸种24 h效果最好,能够提高种子的发芽率、发芽势和发芽指数;大叶山龙眼种子以低温恒温层积处理效果最佳,10 d后就有种子开始萌发,45 d后种子萌发率能达到92%,极显著高于对照。     

Seasonal Fluctuations in the Vertical Distribution of Meiofauna in Estuarine Sediments

The vertical distribution of meiofauna in estuarine sand and mud sediments was investigated over a period of fourteen months. Statistically significant differences were found between fluctuations of meiofauna inhabiting different depth zones in the top 20 cm of the sediment. The shallow populations are affected more drastically during rimes of adverse conditions but they have the ability to respond rapidly to favourable conditions. It is concluded that a combination of physiological adaptation and changes in species composition, rather than seasonal vertical migrations, are responsible for the observed patterns.