Removal Of Apical Bud Research Articles

Growth and yield of Jatropha curcas l. as influenced by different regimes of apical bud removal

Growth and yield of Jatropha curcas l. as influenced by different regimes of apical bud removal

The Effects of Growth Regulators and Apical Bud Removal on Growth, Flowering, and Corms Production of Two Gladiolus Varieties

Gladiolus is commonly propagated from corms. The multiplication rate of corms is low and to increase the propagation rate, we examined a combination of apical bud removal and the application of growth regulators. The experiments were conducted in two varieties, ‘Rose Supreme’ and ‘White Prosperity’, and over two seasons. The apical buds on the planting corms were either removed or left intact before the same corms were soaked in a suspension with either 100 ppm of benzyladenine (BA), 100 ppm of gibberellic acid (GA3), or pure water. The results showed that apical bud removal increased the number of corms and shoots. GA3 had limited the effect on corm and shoot production, but instead resulted in increased total leaf area and leaf weight per shoot. BA, on the other hand, increased the number of corms and shoots. Overall, the removal of the apical bud plus application of BA increased the number of corms and shoots but reduced the average corm diameter and leaf weight per shoot. This was clearer in ‘Rose Supreme’ than in ‘White Prosperity’. To maximize flower production for the coming season, farmers need to produce a high number of planting corms, but they also need to balance this with a sufficient corm size and the production of flowers of good quality. The application of growth regulators in combination with apical bud removal should be fine-tuned to avoid a situation that leads to the production of too many small or too few large corms.

Proteomic Analysis of Chrysanthemum Lateral Buds after Removing Apical Dominance Based on Label-Free Technology

Studying the genetic basis and regulatory mechanism of chrysanthemum lateral bud outgrowth is of great significance for reduction the production cost of cut chrysanthemum. To clarify the molecular basis of lateral bud elongation after removal of apical dominance in chrysanthemum, label-free quantification analysis was used to analyze the proteome changes after apical bud removal. Quantitative real-time PCR (qPCR) was used to analyze the changes in the expression of three plant hormone-related genes. A total of 440 differentially expressed proteins were successfully identified at three time points during the lateral bud elongation. The number of differentially expressed proteins in the three stages (24 h/0 h, 48 h/0 h, 48 h/24 h) were 219, 332, and 97, respectively. The difference in expressed proteins in the three comparison stages mainly involves RNA processing and modification; translation, ribosomal structure and biogenesis; Posttranslational modification, protein turnover, and chaperones. Path analysis showed that there was various physiological activities in the process of lateral bud dormancy breaking and elongation, which involved energy metabolism, biosynthesis, signal transduction and stress response in the growth process of lateral buds. qPCR indicated that the expression of cytokinin synthesis related gene was significantly increased after the removal of apical dominance, while the expression of strigolactones synthesis related gene experiences a dramatic fall to promote the development of the lateral buds. However, there was a drop before a slight increase in the expression of the auxin synthesis related gene, which was mainly due to the removal of apical dominance that led to the loss of indoleacetic acid in the main stem. However, with formation of the new apical source, indoleacetic acid can be released again.

Expression Analysis of DgD14, DgBRC1 and DgLsL in the Process of Chrysanthemum Lateral Bud Formation

The growth of lateral bud can greatly affect the development of apical bud and reduce the quality of single-flower cut chrysanthemum. However, the wide use of artificial bud removal in production leads to the increase on production cost. Therefore, it is important to study the lateral bud development mechanism in chrysanthemum for plant type regulation and genetic improvement. Auxin (IAA), cytokinins (CKs) and strigolactones (SLs) have direct or indirect effects on the formation of lateral buds. D14, BRC1 and LsL are key factors regulating the signal pathways of hormones, but their regulation mechanisms on the development of lateral buds in chrysanthemum are still unclear. In this study, single-flower cut chrysanthemum ‘Jinba’ and spray cut chrysanthemum ‘Fenyan’ were used as experimental materials. Quantitative real-time PCR was used to observe the effects of apical bud removal and exogenous hormones on the growth of lateral buds and the expression levels of DgD14, DgBRC1 and DgLsL, so as to clarify the expression characteristics of three genes in the process of lateral bud formation. The results showed that GA was effective in promoting the growth of lateral buds, whereas IAA and ABA had little effects on lateral bud growth or even inhibited. Removing apical dominance can significantly affect the expression levels of three genes, which regulated the formation and elongation of lateral buds. Additionally, the three genes showed different responses to different hormone treatments. DgD14 had a significant response to GA, but a gentle response to ABA. The expression levels of DgBRC1 varied in different trends, and it responded to IAA in a more dramatic way. The levels of DgLsL reached the peaks quickly before decreased in most experimental groups, and its response to GA was extraordinary severe.

Inhibition of apical dominance affects boll spatial distribution, yield and fiber quality of field-grown cotton

Apical dominance inhibition is important in cotton (Gossypium hirsutum L.) production due to its indeterminate growth habit. Apical dominance can be inhibited physically by the manual removal of apical buds or chemically by the application of plant growth regulators. However, knowledge of the yield and boll distribution of cotton under different methods of apical dominance inhibition remains limited. Thus, an experiment was conducted to evaluate the effects of different methods of apical dominance inhibition (physical inhibition, chemical inhibition and no inhibition) on the plant growth, within-plant boll distribution, crop maturity, yield and fiber quality of cotton from 2016 to 2018. Compared with no inhibition, chemical inhibition and especially physical inhibition reduced plant height, whereas only physical inhibition promoted the ratio of fruiting sites to fruiting branches, which indicated that chemical inhibition resulted in a more compact plant type than physical inhibition. Earlier crop maturity was observed with both physical and chemical inhibition methods than without inhibition, and this finding was attributed to a higher number of inner bolls at lower and middle nodes. The lint yield response to the different inhibition methods varied among years and between varieties. The lint yield of XIN4 was significantly enhanced by physical inhibition and chemical inhibition in 2 of the 3 years, by an average of 11.5 % and 8.7 %, respectively. An effect of inhibition method on the lint yield of CRI60 was observed only in 2016, in which physical inhibition significantly improved the lint yield by 14.0 % compared with that obtained without inhibition. Chemical inhibition achieved a similar lint yield to physical inhibition in all three years. Fiber quality was slightly reduced under chemical inhibition compared to physical inhibition, but the values were within the acceptable range regarding grade standards. Overall, although apical dominance inhibition did not consistently improve lint yield, it remains a desirable management tool for achieving a favorable cotton architecture for mechanical harvest. Additionally, chemical inhibition appears to be a promising alternative to physical inhibition in cotton production due to its simplicity as a management tool.

Brassinosteroid signaling integrates multiple pathways to release apical dominance in tomato

The control of apical dominance involves auxin, strigolactones (SLs), cytokinins (CKs), and sugars, but the mechanistic controls of this regulatory network are not fully understood. Here, we show that brassinosteroid (BR) promotes bud outgrowth in tomato through the direct transcriptional regulation of BRANCHED1 (BRC1) by the BR signaling component BRASSINAZOLE-RESISTANT1 (BZR1). Attenuated responses to the removal of the apical bud, the inhibition of auxin, SLs or gibberellin synthesis, or treatment with CK and sucrose, were observed in bud outgrowth and the levels of BRC1 transcripts in the BR-deficient or bzr1 mutants. Furthermore, the accumulation of BR and the dephosphorylated form of BZR1 were increased by apical bud removal, inhibition of auxin, and SLs synthesis or treatment with CK and sucrose. These responses were decreased in the DELLA-deficient mutant. In addition, CK accumulation was inhibited by auxin and SLs, and decreased in the DELLA-deficient mutant, but it was increased in response to sucrose treatment. CK promoted BR synthesis in axillary buds through the action of the type-B response regulator, RR10. Our results demonstrate that BR signaling integrates multiple pathways that control shoot branching. Local BR signaling in axillary buds is therefore a potential target for shaping plant architecture.

Maleic hydrazide elicits global transcriptomic changes in chemically topped tobacco to influence shoot bud development.

Transcriptomic analysis revealed maleic hydrazide suppresses apical and axillary bud development by altering the expression of genes related to meristem development, cell division, DNA replication, DNA damage and recombination, and phytohormone signaling. Topping (removal of apical buds) is a common agricultural practice for some crop plants including cotton, cannabis, and tobacco. Maleic hydrazide (MH) is a systemic suckercide, a chemical that inhibits shoot bud growth, used to control the growth of apical (ApB) and axillary buds (AxB) following topping. However, the influence of MH on gene expression and the underlying molecular mechanism of controlling meristem development are not well studied. Our RNA sequencing analysis showed that MH significantly influences the transcriptomic landscape in ApB and AxB of chemically topped tobacco. Gene ontology (GO) enrichment analysis revealed that upregulated genes in ApB were enriched for phosphorelay signal transduction, and the regulation of transition timing from vegetative to reproductive phase, whereas downregulated genes were largely associated with meristem maintenance, cytokinin metabolism, cell wall synthesis, photosynthesis, and DNA metabolism. In MH-treated AxB, GO terms related to defense response and oxylipin metabolism were overrepresented in upregulated genes. GO terms associated with cell cycle, DNA metabolism, and cytokinin metabolism were enriched in downregulated genes. Expression of KNOX and MADS transcription factor (TF) family genes, known to be involved in meristem development, were affected in ApB and AxB by MH treatment. The promoters of MH-responsive genes are enriched for several known cis-acting elements, suggesting the involvement of a subset of TF families. Our findings suggest that MH affects shoot bud development in chemically topped tobacco by altering the expression of genes related to meristem development, DNA repair and recombination, cell division, and phytohormone signaling.

Effect of different horticultural techniques on quality flower production of Gladiolus grandiflorus cv. PDKV gold

The investigation entitled “Effect of different horticultural techniques on quality flower production of Gladiolus grandiflorus cv. PDKV Gold” was carried out during kharif season of the year 2017-18 and 2018-19 at Floriculture unit, Department of Horticulture, Dr. PDKV., Akola. Vegetative and flowering parameter of gladiolus as affected by different horticultural techniques such as corm sizes viz. jumbo size corm (> 5.1 cm), large sized corm (3.8 to 5.0 cm), medium (3.2 to 3.7 cm) small size corm (3.1 to 2.5 cm) mechanical removal of apical bud (3.8 to 3.2 cm), half corm division (3.2 to 3.7 cm), soaking of corms in 200 ppm GA3 solution for 24 hr (3.2 - 3.7 cm) and clipping of leaves (3.2 to 3.7 cm) were evaluated under natural agro-climatic conditions of Akola. The experiment was laid out in accordance with Complete Randomized Design with eight treatments replicated three times. Regarding growth parameters it was observed that days required for sprouting of corm, number of shoots per corm, plant height, number of leaves per plant, (at 30, 60, 90 and 120 DAP) length and breadth of leaves, jumbo size corm perform the best as compared to medium, small corms and other treatments with maximum values (3.93 days), (2.03), (49.10, 91.63, 111.27 and 113.10 cm), (3.33, 6.13, 8.87 and 9.33 cm), (85.55 and 2.82 cm). Similar results were observed with flowering parameters. In flowering parameter such as minimum days for spike emergence, days to 1st floret opening, days to 50% flowering (77.78, 82.08, 87.13 days respectively) and maximum number of spikes plant-1 (1.67) and ha-1 (1.48 lakh) was recorded in jumbo size corm than large and small size corm. In case of quality parameter maximum length of spike (103.47 cm), diameter of spike (1.44 cm), length of rachis (55.80 cm), number of florets spike-1 (17.88), diameter of open floret (9.32 cm) and vase life of spike (10.95 days) was observed by plants raised from jumbo sized corm.

Effect of horticultural techniques on corm and cormel production of Gladiolus grandiflorus cv. PDKV gold

The investigation entitled “Effect of horticultural techniques on corm and cormel production of Gladiolus grandiflorus cv. PDKV Gold” was carried out during kharif season of the year 2017-18 and 2018-19 at Floriculture unit, Department of Horticulture, Dr. PDKV., Akola. Vegetative, flowering and yield i.e. corm characteristics of gladiolus as affected by different horticultural techniques such as four different corm sizes, jumbo size corm (> 5.1 cm), large sized corm (3.8 to 5.0 cm), medium (3.2 to 3.7 cm), small size corm (3.1 to 2.5 cm) mechanical removal of apical bud (3.8 to 3.2 cm), half corm division (3.2 to 3.7 cm), soaking of corms in 200 ppm GA3 solution for 24 hr (3.2 - 3.7 cm) and clipping of leaves (3.2 to 3.7 cm) were evaluated under natural agro-climatic conditions of Akola. The experiment was laid out in accordance with Complete Randomized Design with eight treatments replicated three times. Regarding growth parameters it was observed that days required for sprouting of corm, number of shoots per corm, plant height, number of leaves per plant, (at 30, 60, 90 and 120 DAP) length and breadth of leaves, jumbo size corm perform the best as compared to medium and small corms with maximum values (3.93 days), (2.03), (49.10, 91.63, 111.27 and 113.10 cm), (3.33, 6.13, 8.87 and 9.33 cm), (85.55 and 2.82 cm). Similar results were observed with flowering and yield parameters. In flowering parameter such as minimum days for spike emergence, days to 1st floret opening, days to 50% flowering (77.78, 82.08, 87.13 days respectively) and maximum number of spikes plant-1 (1.67) and ha-1 (1.48 lakh) was recorded in jumbo size corm than large and small size corm. Regarding yield parameter maximum number of corms and cormels plant-1(2.23, 19) and ha-1 (2.48, 21.11 lakh), weight of single corm (54.67 g), weight of corms plant-1 (106.85 g) ha-1 (117.93 q) and diameter of corm (6.41 cm) was recorded in jumbo size corm. In case of quality parameter maximum length of spike, diameter of spike, length of rachis, number of florets spike-1 diameter of open floret and vase life of spike was observed by plants raised from jumbo sized corm.

Impact of foliar nutrient sprays, crop and spatial manipulation on seed yield of Callistephus chinensis (L.) Nees

An attempt was made to study the effect of pinching, plant densities and foliar nutrient sprays on seed yield and quality parameters in China aster cv. Powder puff. The experiment comprised of two levels of pinching (P0 = No pinching, P1 = Pinching), three planting densities (D1 = 30 plants m-2, D2 = 36 plants m-2 and D3 = 42 plants m-2) and three levels of commercial nutrient sprays (S1= 3 sprays, S2= 4 sprays and S3 = 5 sprays), constituting a total of 18 treatment combinations replicated thrice in randomized complete block design (RCBD). Pinching at visible bud stage, significantly increased 1000 seed weight (2.18 g) and seed yield (490.85 kg/ha), Increasing the planting density resulted in increased seed yield (485.55 kg/ha) and 1000 seed weight (2.05 g). On the other hand, 4 and 5 nutrient sprays significantly improved seed yield (463.12 kg/ha-) and 1000 seed weight (1.95 g). The results from the study suggest that increased branching with apical bud removal, wider planting space and 4 to 5 foliar applications of multi-nutrient sprays, significantly improves seed yield and quality attributes of transplanted China aster. While suggesting the best combination of pinching, spacing and nutrient sprays, the economics of flower production was duly considered.

Apical bud removal increased seed yield in hemp (Cannabis sativa L.)

ABSTRACTIn plants, apical dominance prevents the development of lateral shoots. It can be overwhelmed by apical bud defoliation, allowing numerous lateral buds to develop into more lateral branches carrying more fruits and possibly increasing seed yield. This study tested this hypothesis on five hemp (Cannabis sativa L.) cultivars in a 2-year field experiment. In comparison to the intact ones, the defoliated plants developed several lateral shoots. The hemp seed yield was significantly influenced by the year of production, the apical bud removal, and the cultivar. The average two-year seed yield of the defoliated plants (715 ± 47 kg/ha) was significantly higher than the yield of the intact plants (568 ± 35 kg/ha). Absolutely the greatest effect of apical bud removal on the seed yield was observed for the cultivar ‘Novosadska konoplja’, where increase was 225 kg/ha (25%); a slightly smaller difference occurred for the cultivar ‘Uniko-B’ (183 kg; 30%), followed by ‘Juso-11’ (140 kg/ha; 27%) and ‘Bialobrzeskie’ (128 kg/ha; 29). Cultivar ‘Beniko’ presented the smallest difference with apical bud removal – 58 kg/ha (15%) yield increase We maintain that hemp producers can achieve a larger seed yield not only by selecting an appropriate cultivar and row distance but also by removing apical buds.

Effect of buds manually removal and their damage by large pine weevil (Hylobius abietis L.) on Scots pine seedlings in Siversky Donets river valley

Large pine weevil (Hylobius abietis L.) damages different organs of Scots pine (Pinus sylvestris L.) seedlings in unclosed plantations, including foliage, buds, stem bark and roots. Simulated damage of respective organs, particularly debudding is one of the ways to evaluate qualitative and quantitative influence of such damage on tree condition.
 The aim of research was to evaluate the dependence of Scots pine seedlings mortality and height increment on artificial and large pine weevil caused bud damage.
 The growth of apical shoots of Scots pine seedlings was registered since the beginning of May to the end of June. Development of new shoots in seedlings with manually bud removal or large pine weevil damage started in beginning of May and continued in July.
 Mortality of Scots pine seedlings with 20% of lateral buds damaged did not differ from that in undamaged plants. The seedlings with apical and lateral buds manually removed as well as with apical and over 70% lateral buds damaged by large pine weevil have died in the year of treatment or damage. The seedlings with apical buds damaged as well as with apical and over 50% lateral buds damaged died in the 4th year after damage.
 Removal or damage up to 50% lateral buds did not affect the growth of Scots pine seedlings. Height increment of seedlings with apical buds manually removed or damaged by large pine weevil did not differ significantly in May and June of the year of treatment or damage. In July the height increment was statistically greater in the variant with manually removal of apical bud.
 Previously suggested scale of Scots pine seedlings bud damage satisfactory reflects the score of large pine weevil injuriousness.
 We can suggest that height increment in the next years after bud damage does not depend on damage way and intensity but mainly on ecological conditions.

Resposta da cultura da soja a diferentes intensidades de injúria nos estágios iniciais de desenvolvimento

Este estudo avaliou os efeitos de diferentes níveis de injúria nos estádios iniciais de desenvolvimento das plantas de soja. Os experimentos foram realizados em duas diferentes safras agrícolas em delineamento de blocos completos casualizados, com 11 tratamentos na primeira e 10 tratamentos na segunda safra, e quatro repetições. A cultivar utilizada foi a 'BRS 133' e os níveis de injúria foram: 1-Testemunha; 2-Remoção de 1 cotilédone; 3-Remoção de ambos os cotilédones; 4-Remoção de ambos os cotilédones + 1 folha unifoliolada; 5-Remoção de ambos cotilédones + ambas as folhas unifolioladas; 6-Remoção de 1 folha unifoliolada; 7-Remoção de ambas as folhas unifolioladas; 8-Corte abaixo das folhas unifoliadas; 9-Remoção do broto das folhas trifolioladas; 10-Desfolha total; 11-Desfolha total + remoção da gema apical (apenas no primeiro ensaio). A injúria foi realizada manualmente e inseticidas foram aplicados semanalmente para impedir injúria por insetos. Os resultados evidenciaram que a produção de soja foi reduzida somente quando a injúria foi severa o suficiente para provocar a redução do estande em consequência da morte de plantas. Isso ocorreu nos tratamentos 5, 10 e 11. Nos demais tratamentos, as plantas foram capazes de se recuperar, o que comprova que o nível de ação de 30% de desfolha que é recomendado para iniciar o controle é seguro e deve ser respeitado pelos sojicultores.

Determining the growth responses of Phyla canescens to shoot and root damage as a platform to better-informed weed-management decisions

Understanding the responses of invasive plants to control methods is important in developing effective management strategies. Lippia (Phyla canescens (Kunth) Greene : Verbenaceae) is an invasive, perennial, clonal forb for which few control options exist for use in the Australian natural and agro-ecosystems it threatens. To help inform management decisions, lippia’s growth responses to damage it may experience during proposed control measures, i.e. cutting, crushing, twisting, were assessed in three glasshouse experiments using either whole plants or plant pieces. Plants quickly recovered from severe damage through growth from shoot and root buds at stem nodes. After shoot and root removal, the relative growth rate of the remaining plant was twice that of controls, suggesting tolerance to damage. Lacking buds, root pieces and isolated stem internodes were incapable of responding. Crushing and cutting individual ramets and plant pieces induced the largest responses, including release of axillary buds on damage or removal of apical buds, but full recovery was not achieved. Lippia will be difficult to control because of its ability to rapidly propagate from stem fragments possessing undamaged or damaged nodes; thus, the full impact of control methods that increase fragmentation (e.g. grazing) should be assessed before implementation. Our results also suggest that the most effective biological agents will be those that limit lippia’s vegetative growth and spread, such as shoot- or crown-feeding insects.

Overcompensation in response to simulated herbivory in the perennial herb Sedum maximum

A positive effect of herbivory on plant reproduction (overcompensation) has been documented mostly in monocarpic plants. Iteroparous perennials can be used to test whether enhanced reproduction in 1 year has negative future consequences as predicted by optimal allocation models. This study was intended to verify this prediction in the iteroparous herb Sedum maximum, applying mechanically simulated herbivory. I monitored 132 labelled S. maximum individuals during 2 years of study. They were randomly assigned to two groups: clipped and control. Infructescence dry mass, total seed dry mass, seed size, germination rate and an increase of root dry mass during the season were assessed in the experimental plants. Since only roots can survive to the next season, root dry mass was considered a reliable measure of allocation to future performance. Clipped plants showed increased fruit and seed dry mass versus the controls, with no other aspect of reproduction affected. Apical bud removal also had a positive effect on increase of root dry mass. The results indicate true overcompensation in response to simulated herbivory with no future costs of increased reproduction. Moreover, increased plant reproduction as a result of herbivory is likely to persist in the following years: clipping increased not only seed production but also root growth. This response is inconsistent with the results of optimal allocation models and the discrepancy is probably due to violation of the resource limitation assumption. Plants adapted to tolerate herbivory seem not to reproduce at the maximum rate when undamaged, but rather withhold resources to be allocated to reproduction after herbivory.

Flooding effects on rapid responses of the invasive plant Alternanthera philoxeroides to defoliation

In experiments under controlled growth conditions it was examined how flooding affected the responses of the invasive plant Alternanthera philoxeroides to defoliation. In drained and flooded conditions, plants were subjected to five defoliation levels: 0, 10, 50, 90% removal of leaf tissue and apex removal (90% leaf tissue plus apical bud removal). Plants were harvested weekly for five weeks. In drained conditions, plant biomasses including total biomass, shoot biomass and root biomass after 50% defoliation rapidly recovered to the control plant level. They were significantly lower for the 90% defoliation and apex removal treatments compared to control plants throughout the experiment. In flooded conditions, total biomass and shoot biomass after 50% defoliation, 90% defoliation, and apex removal treatments could return to control plant levels before the end of the experiment. In 90% defoliation and apex removal treatments root to shoot biomass ratios of both drained and flooded plants were initially much higher than in control plants, but the difference disappeared rapidly. The final biomasses decreased with increased defoliation intensity in drained conditions, but no significant difference was generally found in any of the defoliation treatments in flooded conditions. The rapid re-growth of A. philoxeroides plants after defoliation may partly be responsible for its invasion success. However, defoliation capable of removing 90% of the leaf tissue may be desirable in restricting the growth of this invasive species in drained conditions.

Effect of pruning on growth, leaf yield and pod yields of okra (Abelmoschus esculentus(L.) Moench)

SUMMARYYoung leaves and pods of okra (Abelmoschus esculentus(L.) Moench) are edible, and so a crop management strategy for removing edible leaves while sustaining good pod yields is required. Pruning treatments were imposed on apically debudded okra plants for 3 years to assess effects of removing a quarter, half or three-quarters of the primary branches on growth and fresh leaf and pod yields. Pruning significantly (P<0·05) delayed fruiting by 8–10 days, extended length of harvest duration by 12–15 days and increased number of pods/plant by 10–40% and pod yield by 9–36% more than the control plants which had neither apical bud removal nor pruning. However, no difference in pod weight or pod length was found between these treatments and the control. Three-quarters pruning significantly (P<0·05) increased fresh leaf yield by 29–49%, but not all the leaves were desirable for consumption because of high fibre content. Decreases were seen in the numbers of secondary branches, shoot dry weight and pod yields (by 40–57, 22–36 and 22–30%, respectively, more than a quarter or half pruning). Although early production of pods in the control plants is often important for early maturity and high market prices, the present study found that a delay in fruiting, an extension in length of harvest duration and an increase in pod yield in plants with a quarter or half pruning enhanced staggered production and maximal pod yield. This helps to ensure a better market price and to enable growers avoid a glut on the market. A direct promotional effect of pruning on pod yields provides a possible strategy for growing okra for both leaf and pod harvests. A quarter or half pruning from the upper parts of the main stems of apically debudded plants to ensure good production and quality of leaves and pods is therefore recommended if okra is to be grown for both leaf and pod yields.

Growth of enset (Ensete ventricosum) suckers under different horticultural practices

The influence of three propagation practices and three corm types of enset on the production of suckers was investigated. After removal of apical buds, mother corms were uprooted and immediately replanted, not uprooted from original positions and uprooted and transferred to new planting holes three months later. Three corm types: whole, halved and quartered corms were used. Suckers were harvested one year after removal of apical buds. After harvest, the suckers were sorted into three size groups: undersized, small and medium to large. The number of suckers produced per plot, from four planting holes, ranged from 40 to 141 depending on the treatments. Halved and quartered mother corms, when transferred to new planting holes three months after removal of apical buds, produced fewer suckers. On the other hand, the halved corms, when uprooted and replanted immediately after removal of apical buds or not uprooted from their original growing sites, gave earlier differentiation of buds and produced more suckers. The halved corms also gave more medium to large suckers than whole and quartered corms when evaluated across all the propagation methods. An increase in the number of vigorous suckers from halved corms is possible because of elimination of the strong apical dominance while leaving reasonable portions of the mother corm to sustain initiation, growth and development of suckers. Therefore, halved corms uprooted and immediately replanted or left in situ can be used to produce more suckers with better growth.

Allocation of resources within mountain birch canopy after simulated winter browsing

As a response to browsing, birches are known to produce fewer but larger, more nutritious leaves, with enhanced palatability for herbivores. We simulated winter browsing in ramets of mountain birch (Betula pubescens ssp. czerepanovii) to find out whether it decreases subsequent foliage biomass and alters the number and type of shoots. After removal of a considerable proportion of buds (up to 35%) in late winter, the birches were able to compensate for the lost leaf biomass in the following summer; there were no differences in total leaf biomass between winter‐clipped and control ramets. This indicates that foliage growth was limited by the total amount of stored resources, not by the number of buds. Depending on the position of the buds removed, different mechanisms were responsible for the compensation. After removal of apical buds, the number of leaves decreased significantly but leaves were larger than in control ramets. Removal of the same mass of basal buds – containing similar amount of carbohydrates and proteins as in the treatment removing apical buds – activated dormant buds, especially in apical locations, so that leaf number was similar as in the controls; consequently, size of individual leaves increased only slightly. Thus, while the total leaf biomass in a tree seems to be limited by resources from source organs, the distribution of resources among different canopy sections is controlled by their relative sink strengths. In terms of leaf biomass, apical parts are able to compensate for bud loss by increasing shoot number, basal parts only by increasing leaf size.

Bud removal alleviates negative effects of pollution on quality of Salix borealis for an insect herbivore

Removal of all apical and every second lateral bud from naturally growing young ramets of Salix borealis at the time of bud break improved the quality of the remaining foliage for the willow feeding leaf beetle, Melasoma lapponica , which attained higher weight on debudded host plants from both heavily polluted and unpolluted sites. However, this treatment, as well as removal of apical buds only, caused an increase in larval survival only in polluted sites, where bud removal weakened negative effects of pollution on plant quality. Under natural conditions, amelioration may be induced by winter and early spring bud damage, which is more likely to occur in polluted sites due to thinner snow cover and stronger winds coupled with high ambient concentrations of sulphur dioxide, as well as by early spring herbivore damage. This increase in plant quality may promote the release of leaf beetle outbreaks in “enemy-free space” created by pollution.