Number Of New Shoots Research Articles

Pengaruh Jenis Pupuk dan Konsentrasi Benzyladenin (BA) Terhadap Pertumbuhan dan Pembungaan Anggrek Dendrobium Hibrida

Dendrobium as ornamental plants that are used as cut flowers, potted plants, wreaths, garden ornament has a high economic value (due to the type, beauty, shape, texture, flower size, and rarity), has a broad market opportunities, sources of germplasm as mains to cross in order to get new varieties, and to cultivate them do not require large tracts of land. to get orchid production which is reached with good cultivation, one of them is by using fertilizers and growth regulators (PGR) to obtain growth and good flowering of orchids. This study was conducted to answer the following questions: (1) Which type of foliar fertilizer that can generate the best response to the growth and flowering of orchid Dendrobium, (2) how the effect of benzyladenine (BA) on the growth and flowering of orchid Dendrobium, (3) whether there is an interaction between foliar fertilizers and provision of benzyladenine (BA) to influence the growth and flowering of orchid Dendrobium. The research conducted in the greenhouse, Faculty of Agriculture, University of Lampung from January to June 2014. The experiments were carried out with a complete randomized block design with three replications. The treatments arranged in factorial (2x5). The first factor of 2 types of fertilizers, was (NPK 20-15-15) and (NPK 10-40-15). The second factor is the various concentrations of BA are: 0, 100, 200, 300, and 400 mg/l. based on data and discussion of experimental results that have been raised, it can be concluded as follows: Gandasil fertilizer (NPK 20-15-15) and Hyponex (NPK 10-40-15), had no effect on the growth and flowering of plants Dendrobium hybrids indicated by a variable percentage of plants to germinate, the number of new shoots, the height of new shoots, the increase of leaf pseudo stem diameter, and the percentage of flowering plants. Application of benzyladenine (BA) on the concentration of 100-400 mg / l, can stimulate flowering orchid hybrid Dendrobium, which is indicated by an increase in the percentage of flowering from 60.50 to 64.83%. Application of BA on the concentration of 100-400 mg / l had no effect on the percentage of ornamental plants whis have new sprout, and the number and the height of new shoots. There is no interaction between the two types of NPK (20-15-15 and 10-40-15), with concentrations of BA in influencing all observed variables. Keywords: Dendrobium, Two kinds of completed fertelizers, Benzyladenine, flowering

High temperature promotes growth and flowering in Sophrolaeliocattleya

This study investigated the effects of temperature on vegetative growth and flowering in Sophrolaeliocattleya ‘Red Doll’ and ‘Grace’. Plants were grown at constant temperatures of 8, 13, 18, or 23°C for 12 weeks in environmentally controlled growth chambers. Photosynthetic efficiency was measured four weeks after the start of the temperature treatment. The shoot length, leaf length, leaf width, and the number of new shoots increased in plants from both cultivars that were grown at 18 and 23°C, respectively; whereas the number of days to visible buds and flowering were reduced compared to plants grown at 8 and 13°C. The number of flowering florets and the flower diameter were greater in plants grown at 18 and 23°C than at 8 and 13°C. High photosynthetic efficiency was observed in plants grown at 23°C, which was measured as increased PSII quantum yield, photochemical quenching, and electron transport rate; and decreased non-photochemical quenching. These results indicate that temperatures of 18-23°C promote growth and stimulate earlier production of high-quality flowers in Sophrolaeliocattleya.

EFEKTIFITAS PENAMBAHAN MEDIA ORGANIK EKSTRAK UBI JALAR (Ipomoea batatas L) PADA PERTUMBUHAN SUBKULTUR ANGGREK Cattleya sp.

<p align="center"> </p><p><em>Orchids (Chattleya sp) is popular plant which is favorted by peoples and has higt economic value. It’s price Rp. 562,000 / plant. Tissue culture technique is needed to produce this flower quicky than conventional technique. This study have aims to determine the effect of some medium concentration of organic sweet potato (Ipomoea batatas L) on growing Cattleya sp and for knowing the best of concentration on the growth of Chattleya sp. </em><em>The method used was Completely Random Design (RAL) with four of factors, that is: 0 g / L, 75 g / L, 150 g / L, and 300 g / L. The results were analyzed with Anova test and Duncan test multiple ranger test at the level of 5%. Each treatment was repeated six times. Parameters were observed are the number of new shoots, long leaf, number of leaves, leaf width, long roots, and height of the plant for 5 weeks. Based on the results of analysis showed that the sweet potato extract on 150 g / L concentration give the best results in long root parameter, the concentration of 75 g / L gived the best results to long leaf parameter and concentration of 300 g / L gived the best effect against leaf width. Same concentrations of sweet potato did not give significantly effect to number of new shoots, plantlets height, and number of leaves. </em></p>

The Issues of Apricot (Prunus Armeniaca L.) Micropropagation

The effect of four modified mediums for apricot multiplication was observed in this study. A total number of 1864 single nodes of 20 Prunus armeniaca L.varieties were established. Explants surface was disinfected with 0.2 % mercuric chloride for 5 minutes. MS (1962) medium with 0.5 mg.l−1 BA, 0.01 mg.l−1 NAA and 0.5 mg.l−1 GA3 was used as a medium for primary culture. ‘Velkopavlovická’, ‘Bergeron’, genotype 1128 and genotype LE 2927 Š9 were successfully transferred to aseptic conditions and multiplied. Modified MS medium (1962), DKW/Juglans medium, Quoirin, Lepoivre (1977) medium and Marino et al. (1991) medium were used for multiplication. Modified MS medium and modified DKW/Juglans medium were not suitable for apricot multiplication at all and explants did not grow. The best results were observed in the case of Quoirin, Lepoivre (1977) medium with 0.4 mg.l−1 BA and 0.01 mg.l−1 NAA. Young plants multiplied well, were fresh and vital and no damage was observed. The highest number of new shoots was observed in the case of Marino et al. (1991) medium. The average growth of new shoots after the last passaging was 600 %, rate 7.33 (Velkopavlovická); 566 %, rate 7.0 (Bergeron); 475 %, rate 6.25 (1128) and 483 %, rate 6.33 (LE 2927 Š9)). However, new shoots in clusters were too dense and stunted and this medium is not recommended for apricot multiplication.

Pertumbuhan dan Keragaan Tanaman Jeruk Keprok Borneo Prima pada Dosis Pupuk dan Bentuk Pangkas Berbeda

Borneo Prima Mandarin (Citrus reticulata cv Borneo Prima) is a new local commodity that grown in lowland but has an interesting orange skin. As a new commodity, Borneo Prima Mandarin has to be developed in order to reduce citrus import. The research was conducted in lowland area (250 m above sea level) IPB research station, Sindang Barang, Bogor from February 2014 to February 2015. The aim of this research was to observe the effect of phosphorus and potassium (PK) fertilizer and pruning on the growth and performance of the plants. This research used Randomize Complete Block Design (RCBD) with two factors. The first factor was aplication of PK fertilizer (15 g P+ 10 g K, 15 g P+ 15 g K, 20 g P+10 g K, 20 g P+15 g K per plant) and the second factor was pruning form (without pruning, open center pruning and hedge pruning). The result showed that the combination of phosporus and potassium fertilizer just gave a significant effect to number of shoot. The highest number of new shoots formed by fertilizing 15 g P+10 g K per tree per application. Pruning treatments had significant effect to plant architecture (i.e reduce plant height, land occupation). Open center pruning and hedge pruning made the crown more open that can increase the light interception so that increase the rate of photosynthesis.

Micro Propagation of cv. Basrai (Banana) Using Growth Hormones

The micro propagation response of cv. Basrai (Banana) was studied. The suckers were taken as explants and were cultured on MS with 4, 5, 6 ml of BAP. At the interval of four weeks, removal of black tissues was done. After the cleaning sub culturing was done. At each subculture, data were recorded by counting the number of new shoots produced. Shoot tips of different rhizomes under in vitro condition behaved different. Some cultures give more response while others less and produced less number of shoots. After five sub-culturing from each shoot tip 112 plants were produced, on an average.

Shoot density of Miscanthus sinensis populations in different habitats and their maintenance mechanisms in relation to shoot growth.

How perennial grass populations are maintained in different climates is poorly understood at the level of individual shoots (ramets). During the years 1982-1987 and 1991-1993, measurements of shoot dynamics and growth in populations of a clonal grass, Miscanthus sinensis, were made at two sites in Japan that differed by approximately 5°C in mean temperature. While annual shoot births were very stable during the period 1982-1987 at both sites, the number of flowering shoots fluctuated cyclically every year. The clonal propagation of shoots was size-independent, whereas the reproduction (flowering) of shoots was size-dependent and negatively affected their own offspring size. Shoot size negatively affected the overwintering of shoots. In the warm climate with a long growing period (9months), both early-emerging shoots and the subsequent high order tillering shoots developed in large numbers. In the cool climate with a short growing period (6months), more than half of the annual births occurred in August and September. Nevertheless, average longevity and wintering competency of shoots were not greatly different between the two populations. In response to a warmer climate, tillerings started earlier. This appeared to increase the total number of new shoots that would die within the year; nevertheless, the shoot densities remained much higher because a longer growing season would increase the number of high order tillerings. There was thus a trade-off between the annual survival ratio of new shoots and the number of annual shoot births.

Shooting of Giant Reed (Arundo donax L.) Stem Cuttings in Cold Greenhouse

The increasing interest in Arundo donax, a perennial lignocellulosic species only reproducing by propagation, requires the setup of cheap, simple and reliable techniques. Considering these targets, stem cutting offers considerable advantages. The present investigation aimed to compare: (i) plants obtained by different propagation methods (by rhizome and micropropagation mother plants); (ii) plants obtained by stem cuttings from basal, central and apical parts of the stem; (iii) different planting periods (spring, summer, autumn). The obtained results showed that the number of new shoots from stem buds was: (i) higher in the spring and lower in the summer planting period; (ii) higher from cuttings obtained by micropropagated than rhizome mother plants, both in spring and summer plantings; (iii) decreasing passing from the basal to the apical stem portion; (iv) partly unexpressed in the autumn planting period; (v) lower from one-year stem cuttings as compared to two-year stem cuttings.

Interactive effects of NH4+ concentration and O2 availability on growth, morphology, and mineral allocation of hybrid Napier grass (Pennisetum purpureum × P. americanum cv. Pakchong1)

Biogas production was of increasing interest as it could not only produce biogas, but also treated manure that can be used as fertilizers. However, increasing level of NH4+ in the effluent after anaerobic digestion needed to be considered. Using forage crops with high biomass production for bio-remediation of contaminated wastewater was an interesting alternative for wastewater treatment, but responses of the plants to such wastewater with nitrogen mainly in the form of NH4+ associated with low O2 availability were little known. Hence, growth, morphology, and minerals in plant tissues of hybrid Napier grass (Pennisetum purpureum Schumach×Pennisetum americanum (L.) Leeke cv. Pakchong1) were determined under different combinations of NH4+ (0.5, 1, 5, 10, 15mM) and O2 level (anoxia, hypoxia and normoxia). The plant growth decreased with O2 depletion and strong effects were found in the plants grown in the anoxic condition, particularly, at the high NH4+ concentrations (10, 15mM). Similar results were found for number of roots, root length, and number of new shoots. Mineral concentrations in the plant tissues were affected by the O2 depletion, especially N and P in the roots that decreased by 26% and 50%, respectively, at the absolute anoxic conditions as compared with the normoxic conditions. However, high Fe accumulation was found in the plants grown under the anoxic conditions. The hybrid Napier grass was able to tolerate the high NH4+ up to 5mM and could grow under the hypoxic condition with the total N slightly decreased. This species may have a potential for treating the wastewater discharged from the biogas production tank and at the same time could be used for animal feed or green manure after being harvested.

Influence of Sugar, Ammonium Nitrate and Plant Growth Regulators on in vitro Flowering of Celosia argentea var. cristata

In vitro flowering is considered to be a complex process regulated by a vast of environmental and genetic factors. The present study describes the influence of sugar, ammonium nitrate and plant growth regulators on in vitroflowering from nodal explants of Celosia argentea var. cristata cultured for 6 weeks on basal MS medium under aseptic and light conditions. The addition to MS medium different concentrations of sucrose or ammonium nitrate did not influence on morphogenesis of Celosia plants. Among the plant growth regulators tested, supplementation with 1.0 mg/l KIN induced maximum number of new shoots (2.52). Flowering occurred on 100% of in vitro shoots cultured on modify MS medium supplemented with 16.50 and 8.25 g/l of NH4NO3 after 40 days.

Ex-situ propagation of Pogostemon helferi (Hook. f.) Press using tissue culture and a hydroponics system

Pogostemon helferi (Hook. f.) Press, locally known as “dao-noi” is a rare Thai indigenous aquatic plant that is popular for use in aquaria and water gardens. To address its scarcity and to make the plant more readily available, two experiments were conducted to find the optimum conditions for ex-situ propagation. The first experiment aimed to determine the concentration of growth regulators for its micropropagation. Sterile explants were cultured using a combination of 3-indoleacetic acid (IAA) and 6-benzylaminopurine (BA) supplements in Murashige and Skoog media (MS). MS media containing IAA 0.1 mg/L and BA 3 mg/L induced the highest percentage of callus formation (93.33%). In addition, MS media with IAA added at 0.3 mg/L significantly (p < 0.05) increased the number of new shoots appearing and their length after 8 wk. The second experiment aimed to determine the optimum electrical conductivity of the nutrient solution and the humidity level for P. helferi growth within a hydroponics system. The results showed that an electrical conductivity of 1.6 mS/cm and 80% humidity were optimal for P. helferi growth and production to a marketable size. These methods should enable the production of P. helferi appropriate to support market demand and thus can reduce the current practice of harvesting wild plants in their natural habitat.

基于Hegyi改进模型的毛竹林空间结构竞争动态分析

PDF HTML阅读 XML下载 导出引用 引用提醒 基于Hegyi改进模型的毛竹林空间结构和竞争分析 DOI: 10.5846/stxb201406131227 作者: 作者单位: 浙江农林大学环境与资源学院,浙江省森林生态系统碳循环与固碳减排重点实验室,浙江农林大学环境与资源学院 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金(31170595);国家十二五科技支撑计划(2012BAD22B0503);浙江省重点科技创新团队(2010R50030);教育部留学回国人员科研启动金项目(20101561);国家林业局造林司委托项目(SFA2130218-2) Analysis of the spatial structure and competition with a Phyllostachys edulis standbased on an improved Hegyi model Author: Affiliation: School of Environment and Resource, Zhejiang A & F University,Zhejiang Provincial Key Laboratory of Carbon Cycling in Forest Ecosystems and Carbon Sequestration,Lin’an,Zhejiang Provincial Key Laboratory of Carbon Cycling in Forest Ecosystems and Carbon Sequestration,Lin’an;Management Office,National Nature Reserve of Tianmu Mountain,Lin’an;The forestry specialty bureau of Tiantai country,Tian’tai Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:以浙江省天目山国家级自然保护区内少受干扰的毛竹林为研究对象,设置100m×100m的固定标准地,进行连续5a的每竹调查,用全站仪精确测定每竹坐标(X,Y,Z)。提出新的竞争指数--竞争势(CP)。利用CP对2009-2013年毛竹林分竞争动态进行定量分析,并分别研究各年份毛竹林竞争强度与对象竹胸径、年龄之间的动态关系。结果表明:毛竹大小年现象明显,毛竹大年(2010、2012)的林分竞争强度明显大于小年(2009、2011、2013),且大小年之间竞争强度存在显著性差异(P < 0.01),毛竹大年之间林分竞争强度无显著性差异(P > 0.05),毛竹小年(2011、2013)之间林分竞争强度无显著性差异(P > 0.05),2009年毛竹林受雪灾和新竹株数影响,与其它年份林分竞争强度存在显著性差异(P < 0.01);毛竹林竞争强度随对象竹径阶的增大而减小,且服从幂函数关系;毛竹林竞争强度随对象竹龄级的增大而增大,且服从线性函数关系。CP在Hegyi模型的基础上,增加考虑毛竹生理特性,使对毛竹竞争关系的分析有了进一步拓展,从而更加全面有效地描述毛竹林分的竞争关系,应用CP分析毛竹林竞争动态规律,可为毛竹林经营提供参考依据。 Abstract:At present, many individual tree competition indices are used to measure the competitive ability of trees, and they are generally divided into distance-independent indices and distance-dependent indices depending on whether one is considering the space between trees. Distance-dependent indices are commonly used, especially the Hegyi competition index (CH). The CH was used to analyze the spatial structure of a Phyllostachys edulis stand studied by Tang et al., but we found that this CH needs to be improved. P. edulis is a Bambusoideae (Gramineae) species and does not have secondary cambium tissue, resulting in the termination of diameter at breast height (DBH) growth after completion of the stem growth. Unfortunately, there are different competitive intensities associated with the spatial structure of P. edulis stands, even in situations where the same distance exists between object and competition bamboo plants. This means they might have the same DBH, but would be considered to be of a different age. Such distinctions cannot be provided by the existing CH. In fact, competition within a P. edulis stand is affected significantly by intensity of physiological activity, which changes with variation of the metabolic turnover and aging process of an individual, or with its material growth period. Material growth periods are divided into enhancement stages, stationary stages, and declining stages, depending on different intensity of physiological activities. In the light of characteristic of P. edulis, considering its metabolic turnover and aging process, and adding a material growth period factor, a new competition index-competition potential (CP), which is based on CH (the Hegyi model), was proposed to analyze the spatial structure of P. edulis stands. A permanent plot measuring 100 m × 100 m, including a relatively lightly disturbed P. edulis stand, was established in the Tianmu Mountain National Nature Reserve, Zhejiang province. There have been five annual surveys of the plot. Each bamboo tree was tallied and its coordinates (X, Y, Z) were measured using a total station survey device. From 2009 to 2013, we used the new competition index, CP, to quantitatively analyze the dynamic competition within the bamboo stand, as well as to study the dynamic relationship between intensity competition and DBH, and the dynamic relationship between intensity competition and age class. The results showed that the P. edulis stand has clear on-year/off-year cycles and that the competitive intensity of on-years (2010, 2012) is obviously higher than that of off-years (2009, 2011, 2013). The difference in competitive intensity within the P. edulis stand between on-years and off-years was significant (P < 0.01). The difference in competitive intensity within the P. edulis stand between on-years was not significant (P > 0.05), as was the difference in competitive intensity between off-years (2011and 2013; P > 0.05). Because of a snow disaster and the emergence of a number of new shoots, the competitive intensity within the P. edulis stand in 2009 showed significance difference (P < 0.01) from other years. The competitive intensity within the P. edulis stand decreased with increasing objective diameter class, and the results showed that the competition had a powerful relationship with DBH. The competitive intensity within the P. edulis stand increased with increasing age class and also had a significantly linear correlation with DBH.A combination of the growth characteristics and adopted physiological characteristics of P. edulis was used to develop an expanded analysis of competition between individuals of P. edulis. This allowed us to develop a more comprehensive and effective model (CP) to describe competition within a P. edulis stand. The new CP is therefore a feasible and reliable way to analyze competition within P. edulis stands and their dynamic characteristics. For these reasons, it could provide a theoretical basis for management of artificial P. edulis stands. 参考文献 相似文献 引证文献

The standardization of method and time of propagation in guava (Psidium guajava)

The present investigation on the standardization of method and time of propagation in guava (Psidium guajava L.) was experimented during four different months, viz. June, July, August and September with four different methods, i.e. cuttings, air layering, patch budding and wedge grafting during the year 2012-13. It was observed that among all propagation methods, patch budding performed during 15 to 21 August showed highest per cent success (92.07%) recorded after 90 days of propagation. After 180 days of guava propagation, maximum number of new shoots per plant (8.97), number of leaves/plant (22.39), scion thickness (1.34 cm) were recorded in wedge grafting performed during 15 to 21 September while, air layering during 15 to 21 August took minimum days to sprout (11.75) with maximum increase in plant height (61.89 cm).

Optimalization of Flurprimidol Concentration for Improvement of Acclimatization Rate and In Vitro Growth Inhibition in Bioreactor Culture of Strawberry Plantlets via Bioreactor Culture

This study was conducted to improve the acclimatization rate of in vitro strawberry plantlets through bioreactor culture using the growth retardant flurprimidol. Different concentrations (0 (Control), 0.1, 0.5, 1.0, and 2.0 mg·L -1 ) of flurprimidol were added during bioreactor culture. After six weeks of treatments, various growth characteristics were investigated and in vitro plantlets were acclimated in the greenhouse. The growth rate of treated plantlets was much lower than that of control, and as the treatment concentration increased, the growth rate was much decreased. Shoots of plantlets treated with flurprimidol were shorter (2.2-3.7 cm) than those of control (7.9 cm). The number of roots per treated plant was around 11.6-34.2, compared with 51.8 in the control. Root length was also lower (0.88-3.08 cm) than control (4.36 cm). However, the number of new shoots and leaves increased in all treatments except for 2.0 mg·L -1 concentration. The root was partially decayed in 1.0 mg·L -1 concentration and was completely decayed in 2.0 mg·L -1 . The survival rate in 0.1 mg·L -1 and 0.5 mg·L -1 concentrations was 100% and 23.3% respectively. After four weeks of acclimatization, the plantlets restarted growth, and growth characteristics of shoots and roots recovered to the levels of control, except for fresh weight. Based on our results, a concentration of 0.1 mg·L -1 flurprimidol

Effects of immersion system and gibberellic acid on the growth and acclimatization of micropropagated pineapple

Micropropagation based techniques enable the mass production of pest- and disease-free stock plants. Aiming at optimizing pineapple [Ananas comosus (L.) Merril] micropropagation, a complete randomized experiment with three factors was established: immersion system (2 L twin flasks temporary immersion and permanent immersion); culture medium (supplemented or not with GA3); and shoot height class. The effects on regeneration rate (number of new shoots per 1 g fresh mass (FM) of inoculated microshoots), FM per shoot, and shoot survival were evaluated. Significant interactions (p&lt;0.05) were observed in the regeneration rate, and simple effects (p&lt;0.05) were detected for FM per shoot. All treatments resulted in a survival rate higher than 95%. Altogether, it was found that 2 L twin flasks temporary immersion and MS culture medium free of GA3 allowed the optimization of the protocol used. This treatment was tested with positive response in a biofactory system that uses sterile plastic bottles (5 L).

Chrysopogon zizanioides (vetiver grass) as a potential plant for landslide bioengineering at Atok, Benguet, Philippines

Chrysopogon zizanioides, more commonly known as vetiver grass, is being used extensively for bioengineering in several countries, to stabilise soil. This species has a fast growth rate and can hold soil through its ability to grow on steep slopes. The use of vetiver grass for bioengineering has not yet been explored in the northern Philippines, an area prone to landslides owing to steep slopes, exacerbated by an intense rain fall regime and typhoons. The aim of this study was to validate the use of vetiver grass for stabilisation of an experimental landslide area in Atok, Benguet, northern Philippines, and to monitor its growth performance under nursery conditions. A nursery has been established in Atok for the propagation of vetiver grass and other plant species, with potential for use in stabilising landslides. Three sample plots were chosen randomly. The number of new shoots and shoot length were measured every month from planting. The results show that during the early stages of growth, vetiver grass was able to develop new shoots. The longest shoot increment measured in the nursery was 65 cm and the average number of new shoots was three per pot. During the rain season, the vetiver grass was transplanted to the experimental site. The transplanted vetiver plants were monitored there and, after 2 months, the plants had shown growth and were able to produce more and longer shoots. To assess the capability of the roots to stabilise the soil, a force gauge was used on three vetiver plants and other revegetation species, to measure how strongly the roots can hold soil. The results showed that vetiver grass has a strong soil-aggregation capacity and that the roots were able to establish in the landslide within 2 months.

Vegetative buds, needles and shoot growth of Norway spruce are affected by experimentally delayed soil thawing in the field

Climate change may increase air temperature and decrease snowpack in the boreal zone. Due to declined insulating snow cover, tree roots may be exposed to too low soil temperatures that may be reflected in shoot growth. We studied the effects of soil freezing and delayed thawing on vegetative buds, needles and shoots in a 47-year-old boreal stand of Norway spruce (Picea abies L. Karst). The treatments in two winters of 2005/06 and 2006/07 were: (i) natural snow accumulation and melting (CTRL), (ii) artificial snow removal during winter (OPEN), and (iii) the same as OPEN, but the ground was insulated in early spring to delay soil thawing (FROST). More soil freezing occurred in OPEN and FROST than CTRL, and soil thawing was delayed in FROST as compared to the two other treatments. The formation of new buds, and consequently the number of new shoots were reduced in FROST. The shoot elongation was reduced and the needle cross-sectional area was smaller in FROST compared to OPEN and CTRL. As the soil temperature in both OPEN and FROST was the same during winter, the wintertime soil frost could not be the reason for the changes. Instead, the delayed soil thawing and warming towards summer seemed to hamper the root function and thus reduced the growth of above ground part of the trees. Timing of soil warming in spring appeared to be an important factor for the vegetative bud formation and shoot growth. Thus, on sites prone to soil frost and low soil temperatures, forest management practices should be planned for a proper stand development.

Wild flower harvesting on the Agulhas Plain, South Africa: Impact of harvesting intensity under a simulated commercial harvesting regime for two re-seeding and two re-sprouting fynbos species

We present a simple method for assessing the medium-term sustainability of different flower harvesting intensities (i.e. percentage of number of stems harvested per individual) for two re-seeders and re-sprouters of fynbos plants on the Agulhas Plain in the Cape Floristic Region, South Africa. We interpret our results from an ecological point of view, looking at impacts of harvesting on vegetative re-growth and survival of frequently harvested fynbos species, and an economic point of view, determining the cumulative number of stems harvested per year.We analysed the impact of different harvesting intensities on two obligate re-seeding (Erica corifolia (L.) and Erica imbricata (L.)) and two strongly re-sprouting species (Brunia laevis (Thunb.) and Staavia radiata (L. Dahl)) on different flower farms. Seventy-five randomly selected plants of each species were experimentally harvested in the same way as is done by flower harvesters. Fifteen plants of each species were left as controls (un-harvested) and 15 each were harvested (cut 15–20cm below the inflorescence) such that 25%, 50%, 75%, and 100% of the inflorescences were removed. Harvested stems were labelled and the number of new shoots counted. Additionally we recorded plant height and mortality.100% harvesting resulted in high mortality rates for both re-seeders (for both species 100% of the individuals were dead at the end of the experiment) and resprouters (for one species all 15 individuals were dead at the end of the experiment and for the other species 4 of 15). Re-seeders in particular were highly susceptible to harvesting below the first branching node, which generally also resulted in plant death. Both guilds can survive up to 75% harvesting (resprouters experienced no mortality for one species, while in the other 4 out of 15 died; of the re-seeders, 9 out of 15 died in the one species, while only 1 out of 15 in the other) and are still able to grow in height. For both seeders and resprouters we recommend that flower harvesters do not harvest in young veld. To ensure sufficient seed set and to avoid seed bank depletion we recommend to preferably only harvest between 25 and 50% of stems per individual.

TREE JOINTING AND BRANCH BENDING INFLUENCE ENDOGENOUS LEVELS OF HORMONES AND FLOWERING IN JAPANESE PLUM 'KIYO'

The joint tree training system was developed in Japan as a horticultural intervention to promote flower induction (FI) in fruit trees. In this system, the apical tip of one tree is artificially grafted into the bent main stem of another in a row of three or more trees. The system reportedly facilitates faster establishment of the tree framework leading to faster FI and high productivity of the orchard earlier than those utilizing traditional systems. Plant hormones are putative bio regulators of flower induction and development. However, changes in phytohormone levels as a result of this cultural intervention have not been reported. To investigate this, 5-year old trees of 'Kiyo' Japanese plum (Prunus salicina) in containers were either bent and jointed into a row of three trees (Bent-Joint group), or individually bent (Bent group). Upright individual trees served as control. Young leaves were analyzed for phytohormone content by ultra-performance liquid chromatography-electrospray ionization tandem mass spectrometry (UPLC-ESI-MS/MS). Our results showed that both the Bent and Bent-Joint groups have significantly lower concentrations of the bioactive gibberellins (i.e., GA1, GA3 and GA4), but higher abscisic acid (ABA) content compared to the control. Consistent with the implicated role of GA as suppressor, and ABA as inducer of FI, both the Bent and Bent-Joint groups registered high flowering rates. Fruit-set was also observed in these groups, while the control had none. The number of new shoots did not significantly vary across treatment groups. Yet control trees, having relatively high bioactive GAs and low ABA contents, exhibited the most vigorous shoot elongation. These findings suggest that the joint tree training system appear to favor FI and fruit-set over vegetative growth that may have resulted from the observed low levels of bioactive GAs and high ABA content.

Plant selection and avoidance by the Bornean elephant (Elephas maximus borneensis) in tropical forest: does plant recovery rate after herbivory influence food choices?

Abstract:The plant vigour hypothesis proposes that herbivores should favour feeding on more vigorously growing plants or plant modules. Similarly, we would expect herbivores to favour plants that regrow vigorously after herbivory. Larger animals, like elephants, may also select plant species relative to their availability and prefer species with larger growth forms in order to meet their intake requirements. The food preferences of the Bornean elephant (Elephas maximus borneensis) in the Lower Kinabatangan Wildlife Sanctuary, Sabah, Malaysia, were investigated along 12 transects in areas where elephants were recently sighted feeding. One hundred and eighty-two plants were eaten and 185 plants were measured for species availability along transects. Species vigour was determined by the monthly regrowth in new shoot length after elephant feeding and the number of new shoots produced on each plant. Measurements were carried out on each plant for 9 mo or until the new shoot was eaten. Plant sizes were determined from their basal diameter. The Bornean elephant did not prefer more vigorous species or species with larger growth forms. New shoots did not grow longer on preferred than avoided species. Additionally, unlike other elephants that live in a forest environment, the Bornean elephant preferred species from the Poaceae (specifically Phragmites karka and Dinochloa scabrida) over other plant types including gingers, palms, lianas and woody trees.