Removal Of Apex Research Articles

Sweetpotato vine management for confined food production in a space life-support system

Sweetpotato ( Ipomea batatas L.) ‘Whatley–Loretan’ was developed for space life support by researchers at Tuskegee University for its highly productive, nutritious storage roots. This promising candidate space life-support crop has a sprawling habit and aggressive growth rate in favorable environments that demands substantial growing area. Shoot pruning is not a viable option for vine control because removal of the main shoot apex drastically inhibits storage-root initiation and development, and chemical growth retardants typically are not cleared for use with food crops. As part of a large effort by the NASA Specialized Center of Research and Training in Advanced Life Support to reduce equivalent system mass (ESM) for food production in space, the dilemma of vine management for sweetpotato was addressed in effort to conserve growth area without compromising root yield. Root yields from unbranched vines trained spirally around wire frames configured either in the shapes of cones or cylinders were similar to those from vines trained horizontally along the bench, but occupying only a small fraction of the bench area. This finding indicates that sweetpotato is highly adaptable to a variety of vine-training architectures. Planting a second plant in the growth container and training the two vines in opposite directions around frames enhanced root yield and number, but had little effect on average length of each vine or bench area occupied. Once again, root yields were similar for both configurations of wire support frames. The 3–4-month crop-production cycles for sweetpotato in the greenhouse spanned all seasons of multiple years during the course of the study, and although electric lighting was used for photoperiod control and to supplement photosynthetic light during low-light seasons, there still were differences in total light available across seasons. Light variations and other environmental differences among experiments in the greenhouse had more effects on vine length than on root yield. Average vine length correlated positively with total hours of daylight received across seasons, and responses for one plant per container were higher above a threshold duration of solar exposure, suggesting that the vines of two plants per container compete for available light. In addition to the adaptability of sweetpotato to various vine-training architectures and across seasons in terms of maintaining root productivity, the open, interior volumes of the support frames tested in this study will provide future opportunity to enhance sweetpotato root yield in space by adding novel interior lighting, such as from intracanopy arrays of light-emitting diodes. This work was sponsored by NASA grant NAG 5 1286.

Effects of shoot tipping on development and yield of the tuber crop Plectranthus edulis

SUMMARYPlectranthus edulis (Vatke) Agnew is one of the tuber crops of the genus Plectranthus that is widely cultivated in Africa and Asia. P. edulis produces below-ground tubers on stolons originating from the stems, comparable to the potato (Solanum tuberosum L.). Farmers apply several laborious cultural practices to enhance shoot growth and yield, among which shoot tipping is very common. Tipping (pinching) is the removal of the shoot apex with one or two pairs of leaves from the main stems and branches. The rationale of this practice, especially when repeated more than once during one cropping season, is not fully understood. One similar experiment with two cultivars was carried out at two locations (Awassa and Wondogenet) in Ethiopia to assess and analyse the effects of shoot tipping and its frequency on crop development and tuber production. Tipping treatments included zero tipping, tipping once, tipping twice and tipping thrice, with the first tipping taking place 68 days after planting (DAP), a stage at which most of the stems reached a height of about 0·15 m, and the remainder following at intervals of 44–46 days. Tipping stimulated stem branching; it significantly increased the number of primary, secondary and tertiary stems in both experiments. Soil cover increased with an increase in the frequency of the tipping in Awassa, because of the tipping effects on the different canopy development variables. Tipping also enhanced the soil cover in Wondogenet, but the crop did not gain any extra benefit from a third tipping. Tipping enhanced early stolon formation, but did not consistently affect the number of stolons per hole later in the growing season. The number of tubers increased with an increase in the frequency of tipping in both cultivars in Wondogenet and in one cultivar in Awassa. Tuber dry matter yield increased with an increase in the frequency of tipping at both sites. Fresh tuber yield in the final harvest at 208 DAP was c. 1·9 kg/m2. Tipping on average increased fresh tuber yield by 17% in Wondogenet, whereas the difference was not detectable in Awassa. Because senescence was delayed slightly by tipping, yield effects of tipping might be larger when harvesting later. In general, there was a positive effect of tipping on canopy development and tuber yield.

Strigolactone may interact with gibberellin to control apical dominance in pea (Pisum sativum)

The role of strigolactones as plant growth regulators has been demonstrated through research on biosynthesis and signaling mutant plants and through the use of GR24, a synthetic analog of this class of molecules. Strigolactone mutants show a bushy phenotype and GR24 application inhibits the growth of axillary buds in these mutants, thus restoring the phenotype of a wild plant, which is characterized by a stronger apical dominance. In this work, we tested the effectiveness of this chemical on pea (Pisum sativum) plants following apex removal, which disrupts apical dominance and leads to axillary bud outgrowth. Moreover, we searched for relationships between the response to the strigolactone and gibberellin metabolism by applying GR24 to both climbing and dwarf peas, the latters being mutants for gibberellin biosynthesis. The results suggest that the endogenous level of the bioactive gibberellin GA1 might modulate the response of decapitated pea plants to GR24, by changing bud sensitivity to the applied strigolactone.

How I do it: epidural anterior petrosectomy

Among the potential approaches to access the petroclival area, epidural anterior petrosectomy (EAP) appears to be the most direct and conservative transpetrous route. In this article, we aim to detail the relevant surgical steps necessary to perform EAP in a reproducible and safe manner. The temporo-pterional bone flap is tailored to access the floor of the middle fossa and expose the foramen ovale and foramen spinosum. Elevation of the dura covering the upper surface of the petrous apex is conducted medially toward the level of the petrous ridge. Identification of the landmarks of the rhomboid fossa delineates the limits of the drilling zone (necessary for removal of the petrous apex)-beneath Meckel's cave and just anterior to the anterior margin of the internal auditory meatus. The tentorium is divided at its free edge and is followed by opening of the posterior fossa dura. Epidural anterior petrosectomy is a conservative trans-petrous approach that offers an excellent direct surgical corridor for exposure of disease processes involving Meckel's cave, the petroclival area and the ventrolateral pons.

Axillary bud development in pineapple nodal segments correlates with changes on cell cycle gene expression, hormone level, and sucrose and glutamate contents

During the process of lateral organ development after plant decapitation, cell division and differentiation occur in a balanced manner initiated by specific signaling, which triggers the reentrance into the cell cycle. Here, we investigated short-term variations in the content of some endogenous signals, such as auxin, cytokinins (Cks), and other mitogenic stimuli (sucrose and glutamate), which are likely correlated with the cell cycle reactivation in the axillary bud primordium of pineapple nodal segments. Transcript levels of cell cycle-associated genes, CycD2;1, and histone H2A were analyzed. Nodal segments containing the quiescent axillary meristem cells were cultivated in vitro during 24 h after the apex removal and de-rooting. From the moment of stem apex and root removal, decapitated nodal segment (DNS) explants showed a lower indol-3-acetic acid (IAA) concentration than control explants, and soon after, an increase of endogenous sucrose and iP-type Cks were detected. The decrease of IAA may be the primary signal for cell cycle control early in G1 phase, leading to the upregulation of CycD2;1 gene in the first h. Later, the iP-type Cks and sucrose could have triggered the progression to S-phase since there was an increase in H2A expression at the eighth h. DNS explants revealed substantial increase in Z-type Cks and glutamate from the 12th h, suggesting that these mitogens could also operate in promoting pineapple cell cycle progression. We emphasize that the use of non-synchronized tissue rather than synchronous cell suspension culture makes it more difficult to interpret the results of a dynamic cell division process. However, pineapple nodal segments cultivated in vitro may serve as an interesting model to shed light on apical dominance release and the reentrance of quiescent axillary meristem cells into the cell cycle.

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.

Effects of top excision on the potassium accumulation and expression of potassium channel genes in tobacco

The effects of the removal of the shoot apex of tobacco on the relative transcript levels of potassium channel genes, determined by real-time PCR, and on the relationship between the expression of genes encoding potassium channels and potassium concentration, were studied. The results from the study indicated that comparatively more assimilates of photosynthesis were allocated to the apex in control plants than in both decapitated and IAA-treated decapitated plants. By contrast, dry matter in the upper leaves, roots, and stems in both decapitated and IAA-treated plants was significantly increased relative to control plants. The potassium level in whole plants decreased post-decapitation compared with control plants, and so did the potassium concentration in middle and upper leaves, stem, and roots. Expression of NKT1, NtKC1, NTORK1, and NKT2 was inhibited by decapitation in tobacco leaves with a gradual reduction after decapitation, but was induced in roots. The relative expression of NKT1, NTORK1, and NKT2 in tobacco leaves was higher than that in roots, whereas the expression of NtKC1 was higher in roots. The levels of inhibition and induction of NKT1, NtKC1, NTORK1, and NKT2 in leaves and roots, respectively, associated with decapitation were reduced by the application of IAA on the cut surface of the decapitated stem. Further results showed that the level of endogenous auxin IAA in decapitated plants, which dropped in leaves and increased in roots by 140.7% at 14 d compared with the control plant, might be attributed to the change in the expression of potassium channel genes. The results suggest that there is a reciprocal relationship among endogenous auxin IAA, expression of potassium channel genes and potassium accumulation. They further imply that the endogenous IAA probably plays a role in regulating the expression of potassium channel genes, and that variations in expression of these genes affected the accumulation and distribution of potassium in tobacco.

Nicotine Concentration in Leaves of Flue‐cured Tobacco Plants as Affected by Removal of the Shoot Apex and Lateral Buds

It is believed that the nicotine concentration in tobacco is closely correlated with the amount of nitrogen (N) supplied. On the other hand, N uptake mainly occurs at the early growth stage, whereas nicotine concentration increases at the late growth stage, especially after removing the shoot apex. To identify the causes of the increased nicotine concentration in tobacco plants, and to compare the effects of different ways of mechanical wounding on nicotine concentration, field experiments were carried out in Fuzhou, Fujian Province in 2003 and 2004. Excision of the shoot apex had almost no influence on N content in the plant; however, it caused dramatic increases in nicotine concentration in leaves, especially in the middle and upper leaves. An additional increase of the nicotine concentration was obtained by removal of axillary buds. The wounding caused by routine leaf harvests, however, did not change the leaf nicotine concentration, and neither did reducing leaf harvest times. The present results revealed no direct relationship between N supply and nicotine concentration in tobacco leaves, and indicate that not all kinds of mechanical wounding were capable of stimulating nicotine synthesis in tobacco plants. Since nicotine production is highly dependent on the removal of apical meristems and hence on the major sources of auxin in the plant, and application of 1-naphthylacetic acid onto the cut surface of the stem after removing the shoot apex markedly decreased the nicotine concentration in different leaves and the total nicotine content in the plant, the results suggest that decreased auxin supply caused by removal of the shoot apex as a kind of mechanical wounding might regulate nicotine synthesis in the roots of tobacco plants.

Tobacco plants can use nitrogen taken up before mechanical wounding to synthesize nicotine afterwards

Mechanical wounding stimulates nicotine synthesis in tobacco plants. In the practice of tobacco production, most nitrogen (N) is taken up before removal of the shoot apex, while nicotine is mainly synthesized afterwards. Since N is required for nicotine synthesis, it is interesting to know whether plants can use N taken up before removal of the shoot apex to synthesize nicotine after wounding. To address this question, a hydroponics culture experiment was carried out, in which N was supplied as NH4NO3 at two levels (1 mM and 6 mM) in pre-culture, and N was either withdrawn or replaced by 15N after removing the shoot apex for the next 7 days. Removal of the shoot apex caused a marked increase in nicotine concentration in various organs, also when plants grew under low-N conditions and showed symptoms of N deficiency. Increased nicotine accumulation even occurred when N was withdrawn from the growth medium before the apex was removed, indicating that tobacco plants can use N taken up previously to synthesize nicotine after mechanical wounding. The amount of N used for nicotine synthesis accounted for 5-6% of the total N, irrespective of treatment. Although most of the nicotine in intact plants and plants with the apex removed was synthesized de novo, as evidenced by the data when N was replaced by 15N-labeled NH4NO3, a large amount of the N absorbed before the N replacement was incorporated into the newly formed nicotine. The proportion of nicotine-15N to total nicotine-N was almost the same as that of 15N to total N in various organs. The results show the utilization of remobilized N taken up before excision of the shoot apex for nicotine synthesis afterwards, and highlight the importance of N cycling within plants, both when grown under N-sufficient and N-deficient conditions.

Shoot Apex Demand Determines Assimilate and Nutrients Partitioning and Nutrient‐uptake Rate in Tobacco Plants

Abstract Our previous experiment revealed that apex‐removed plants have larger root systems but a lower K+‐uptake rates than intact tobacco plants. Since the apex is not only a center of growth and metabolism, but also an important place of auxin synthesis and export, the aims of this study were to distinguish whether the apex demand or auxin synthesized in the apex regulates assimilate and nutrients partitioning within plant, and to explain the reason for the lower K+‐uptake rate of the apex‐removed plant. In comparison with the control plant, covering the shoot apex with a black transparent plastic bag reduced net increases in dry matter and nutrients; however, the distribution of the dry matter and nutrients between shoot and roots and nutrient‐uptake rates were not changed. Removal of the shoot apex shifted the dry mass and nutrients distributions to roots, and reduced the rate of nutrient uptake. Application of 1‐naphthylacetic acid (NAA) could partly replace the role of the removed apex, stimulated assimilate and nutrient deposition into the treated tissue, and enhanced the reduced plasma membrane ATPase activity of roots to the control level. However, treatment of the apex‐removed plants with NAA could not rescue the reduced nutrient uptake rate and the shifted assimilates and nutrients partitioning caused by excision of the apex. Higher nutrient uptake rate of the intact plants could not be explained by root growth parameters, such as total root surface area and number of root tips. The results from the present study indicate that strong apex demand determined assimilates and nutrients partitioning and nutrient‐uptake rate in tobacco (Nicotiana tabacum) plants.

Tolerance to apical and foliar damage: costs and mechanisms in Raphanus raphanistrum

To study mechanisms underlying plant tolerance to herbivore damage, we used apical and foliar damage as experimental treatments to study whether there are similar tolerance mechanisms to different types of damage. We also studied whether tolerance to different types of damage are associated, and whether there is a cost involved in plant tolerance to different types of herbivore damage. Our greenhouse experiment involved 480 plants from 30 full‐sib families of an annual weed Raphanus raphanistrum, wild radish, which were subjected to control and two different simulated herbivore damage treatments, apex removal and foliar damage of 30% of leaf area. Apical damage significantly decreased seed production, whereas foliar damage had no effect. There was a significant genetic variation for tolerance to foliar, but not apical damage. No costs were observed in terms of negative correlation between tolerance to either damage type and fitness of undamaged plants. Tolerances to apical and foliar damage were not significantly correlated with each other. We observed a larger number of significant associations between tolerance and reproductive traits than between tolerance and vegetative traits. Plant height and leaf size of damaged plants interacted in their association to tolerance to foliar damage. Inflorescence number and pollen quantity per flower of damaged plants were positively associated with tolerance to apical damage. In late‐flowering genotypes, petal size of undamaged plants and pollen quantity of damaged plants were positively associated with tolerance to foliar damage. In summary, traits involved in floral display and male fitness were associated with plant tolerance to herbivore damage.

Growth, chemical responses and herbivory after simulated leaf browsing in Combretum apiculatum

Vegetative and chemical responses to simulated leaf browsing during the growth season, and their subsequent effect on herbivory, were studied on Combretum apiculatum Sonder (Combretaceae) in Botswana. Treatments (50% and 100% leaf and shoot apex removal) were performed just before the shoot growth curve levelled out, and responses recorded 3 months later, just before leaf fall. Compared to controls, defoliation treatments, removing apical dominance, reduced growth in tree height and increased shoot mortality, although the production of lateral shoots increased. At the end of the trial, there was no difference in total length of annual shoots between treatment groups. Significant refoliation occurred only after 100% defoliation. Refoliated leaves were smaller and the 100% defoliated trees had a lower final leaf biomass. Total leaf biomass production was, however, equal for all treatment groups. Refoliated leaves contained higher levels of N, lower levels of acid-detergent fibre (ADF) and total phenolics, and showed a trend towards lower levels of condensed tannins, compared to leaves on control trees. Such chemical changes may be due to either carbon stress or to younger physiological age of new leaves. In spite of the observed potential increase in food quality, we found no evidence of increased levels of insect or ungulate herbivory on refoliated leaves, which, at least for insect herbivory, may be explained by the reduction in temporal availability of leaves. We conclude that the single severe defoliation was not detrimental to C. apiculatum in the short-term, although the resource loss and induced compensatory growth may produce negative effects during subsequent growth seasons.

Nicotine synthesis in Nicotiana tabacum L. induced by mechanical wounding is regulated by auxin

The effects of different kinds of mechanical wounding on nicotine production in tobacco plants were compared, with sand or hydroponics culture under controlled conditions. Both removal of the shoot apex and damage of the youngest unfolded leaves nos 1 and 2 by a comb-like brusher with 720 punctures caused an increase in nicotine concentration in whole plants at day 3, and reached its highest level at day 6. The nicotine concentration induced by excision of the shoot apex was much higher than that induced by leaf wounding. Both treatments also caused an increase in jasmonic acid (JA) concentration within 90 min in the shoot, followed by an increase in the roots (210 min), in which the JA concentration induced by leaf wounding was significantly higher than that induced by excision of the shoot apex. The increase in nicotine concentration occurred throughout the whole plant, especially in the shoot, while the increase in JA concentration in the shoot was restricted to the damaged tissues, and was not observed in the adjacent tissues. Removal of the lateral buds that emerged after excision of the shoot apex caused a further increase in nicotine concentrations in the plant tissues. Removal of mature leaves, however, did not cause any changes in nicotine concentration in the plant, even though the degree of wounding in this case was comparable with that occurring with apex removal. The results suggest that the nicotine production in tobacco plants was not correlated with the degree of wounding (cut-surface or punctures), but was highly dependent on the removal of apical meristems and hence on the major sources of auxin in the plant. Furthermore, immediate application of 1-naphthylacetic acid (NAA) on the cut surface after removing the shoot apex completely inhibited the increase both in nicotine in whole plants and in JA in the damaged stem segment and roots. Application of an auxin transport inhibitor around the stem directly under the shoot apex of intact plants also caused an increase in nicotine concentration in the whole plant. The results strongly suggest that auxin serves as a negative signal to regulate nicotine synthesis in roots of tobacco plants.

Plasticity of clonal integration in the perennial herb Linaria vulgaris after damage

1 Clonal integration in plants can improve their ability to cope with habitat heterogeneity. Integration may increase in response to damage, such as herbivore attack, if undamaged ramets support damaged ones. To test this, we studied the effects of apex removal and substantial defoliation on the performance of the clonal perennial herb Linaria vulgaris Mill. in a common-garden growth experiment and a 13C-labelling study. 2 In the growth experiment, contrary to expectations, the target ramet could compensate for damage better when the other ramets in the clone were also damaged, indicating within-clone competition for resources rather than support to damaged ramets. 3 In the 13C-labelling experiment, 5·7% of the label moved to a neighbour ramet in controls. Apex removal resulted in a negative net translocation of 13C in the damaged ramet, but defoliation led to zero net translocation. 4 The observed lack of support to damaged ramets in Linaria suggests that plasticity of clonal integration in this species includes competition between sibling ramets. Although young ramets may be supported, resources are not directed towards a single damaged ramet if there are more viable intact ramets in the clone. Our main results are consistent with the notion that resource allocation among ramets depends on their relative value in terms of expected fitness profits in heterogeneous environments.

視神経障害に注意が必要な脳動脈瘤手術における低侵襲手術

Direct surgery of paraclinoid aneurysms that could require anterior clinoidectomy for exposure, or of some basilar head aneurysms that could require going deep through the opticocarotid triangle for access, may injure the optic nerve. And also in surgery of large or giant aneurysms of the internal carotid artery that could compress the optic nerve, recovery and preservation of visual function, or sometimes even prevention from the worse, could become important issues. We describe less invasive surgical techniques in surgery of aneurysms that may injure the optic nerve, based on our experience in 36 cases selected from among 528 aneurysm surgeries of the past 11 years. The safe and easy method of anterior clinoidectomy that includes the following components may be useful: 1) drilling of the orbital roof, the lateral part of the anterior clinoid process and the optic canal should be performed though the extradural route, and 2) removal of the residual apex of the anterior clinoid process should be completed after moving to subdural space when the dura covering the process has been cut and pealed off. A longer cut of the falciform ligament could be useful to make the optic nerve movable and to widen the opticotriangle space. A suction decompression technique for large and giant aneurysms should effectively ensure safe clipping near the optic nerve.

Skull Base Chondrosarcoma Originating from the Petroclival Junction

To define the presentation of patients with skull base chondrosarcoma, to elucidate surgical strategies, and to identify the role of postoperative radiotherapy. Retrospective review. Tertiary referral center. All patients (n = 33) with skull base chondrosarcoma managed at our institution. The average follow-up time was 7.7 years (range, 0-20 years). Tumor location, presenting symptoms, presence of residual or recurrent tumor, and mortality. The most common tumor location was the petroclival junction (n = 29). Common presenting symptoms were diplopia (48%) and headache (45%). Surgical approaches included retrosigmoid, transtemporal, transfacial, and frontotemporal craniotomies. Biopsy only was performed in four patients, subtotal resection in 19 patients, and total resection in nine patients. Most patients received postoperative radiotherapy (82%). Follow-up revealed residual, stable disease in 28% of patients and recurrent disease in 24% of patients. The mean time to recurrence was 3.0 +/- 2.8 years. The lack of postoperative radiation was significantly correlated with an increased risk of recurrence (odds ratio, 28; p = 0.007) but incomplete tumor resection was not (p = 0.6). Life-table analysis revealed that the 5-year survival rate was 85% and the 10-year survival rate was 77%. Five patients died; four of the deaths attributable to recurrent disease. The characteristic growth pattern of skull base chondrosarcoma is tumor eroding the petroclival junction. Current therapeutic strategy is resection through an extradural subtemporal craniotomy with removal of the petrous apex and clivus. Radical resection of uninvolved structures is often not necessary. Nonetheless, gross total removal is often achievable. Postoperative radiotherapy reduces the chance of tumor recurrence.

Nitrogen supply after removing the shoot apex increases the nicotine concentration and nitrogen content of tobacco plants.

and Aims High nicotine concentrations in leaves, especially in the upper leaves, offer a serious problem for the cultivation of tobacco (Nicotiana tabacum). Preliminary field experiments showed that rapid mineralization of soil N during late stages of growth may contribute to high nicotine concentrations in leaves. A sand-culture experiment was carried out in the greenhouse. The N supply was controlled during the experiment, and different amounts of 15N were supplied during late stages of growth (after removal of the shoot apex), to investigate the contribution of the N taken up at this time to the N content of and nicotine concentration in tobacco plants. Addition of 1.6 g or 4 g 15N-labelled NH4NO3 after removing the shoot apex and flushing out the 14N did not increase leaf dry weights; however, it did result in delayed leaf senescence, more lateral bud formation, and an increase in 15N as a proportion of total N, and nicotine-15N as a proportion of total nicotine-N in each organ. The nicotine concentration, 15N and nicotine-15N abundances were increased from the bottom to the top leaves. When more 15N-labelled NH4NO3 was supplied, the nicotine concentration in leaves increased, and so did the 15N abundance in nicotine-N. Enhanced N supply in the later growth stages (after removing the apex) increased N content and nicotine concentration in tobacco plants. Nicotine was synthesized de novo during the late growth stages.

Transcavernous approach to diseases of the anterior upper third of the posterior fossa

The region in the upper anterior third of the posterior fossa is a surgically hidden, narrow corridor between the petroclival surface anteriorly and the surface of the brainstem posteriorly. Although several approaches have been described to help surgeons reach this region, few of them enable practitioners to reach the different corners of the area and provide as wide a view as the one achieved using the transcavernous route. A transcavernous approach was used in 91 cases (50 complex upper basilar artery [BA] aneurysms, 30 upper petroclival junction meningiomas, five trigeminal nerve schwannomas, three upper clival chordomas, and three anterior pontine lesions) involving the anterior upper third of the posterior fossa. The approach uses the pretemporal route with exposure of the lateral wall of the cavernous sinus. It entails removal of the anterior clinoid process. The posterior clinoid process is also removed when necessary. The approach leads to the upper basilar region. It is widened inferiorly to expose the anterior aspect by removal of the posterior clinoid process and the petroclival osseous and dural elements. Its lateral extension exposes the region of the Meckel cave and it can be widened by removal of the petrous apex. Seventy patients experienced new transient mild cranial neuropathies, 67 of whom recovered fully. Surgically related ischemic morbidities occurred in three patients with BA aneurysms (one small medial thalamic infarct, ataxia due to superior cerebellar artery ischemia, and distal middle cerebral artery embolus in a patient with atrial fibrillation in whom anticoagulation therapy was stopped). All the neuropathies in patients with BA aneurysms were oculomotor and recovery was the rule in all of them. Three new permanent cranial neuropathies occurred in the patients with meningiomas. In seven patients with preoperative neuropathy, two had partial improvement. Five patients with atypical meningiomas were treated with postoperative radiation therapy. Progression occurred later in four patients who were treated with gamma knife surgery. There were no surgery-related deaths. More than 1 year of follow-up data were available in 85 patients, and 94% of those patients were in an active and functional state (Glasgow Outcome Scale scores of 4 and 5). The safety achieved with the transcavernous route allows surgeons to achieve wide exposures to lesions involving the anterior upper third of the posterior fossa. It is an approach that should be mastered by every neurosurgeon dealing with cranial lesions.

PLANNING OF GLOBE ARTICHOKE PLANTLETS PRODUCTION IN NURSERY

The conventional method for globe artichoke propagation is based on the use of offshoots, ovoli (underground dried shoots with apical and lateral buds), portion of stump, etc. There is no special technique, fact, they are harvested commercial field for head production. The effectiveness of this procedure is obviously very limited and constitutes a serious obstacle to the development of this plant as a modern crop. The purpose of this research was to develop a nursery procedure for producing artichoke plantlets. The trials started the summer of 2001 and were supported by MiPA Artichoke project. Trials were carried out Sicily (South Italy) using two new clones from in vitro micropropagation of cv. Romanesco clone C3 and clone 9/8 from cv. Violetto di Sicilia. The planning for plantlets production consisted of three phases: 1) obtaining offshoots of some age from the mother plant by removing the apex and epigeal part of plant; 2) preparation of the offshoots from transplantation; 3) offshoots transplant and plantlets production the nursery. The mean number of offshoots produced by each mother plant was about 20 for 'clone 9/8' and 17 for 'clone C3'. The percentage of obtained plantlets was about 83% of total offshoots transplanted. The time from apex removal of mother plant to offshoots production was on average 35 days, whereas the time from offshoots transplant to plantlets produced, which was not different between the two clones, significantly increased with delaying the time of transplant (from June to October).

Extended middle fossa approach to the petroclival junction and anterior cerebellopontine angle.

This article seeks to demonstrate the use of the extended middle cranial fossa approach in the treatment of tumors arising in the anterior cerebellopontine angle and petroclival region. We conducted a retrospective chart review. Tertiary referral center. : Ten-year retrospective chart review of over 800 skull base surgical cases demonstrated 16 cases in which the senior author used the extended middle cranial fossa as the sole approach to access the posterior cranial fossa, petroclival junction, or the anterior cerebellopontine angle. There were five males and 11 females, 13 meningiomas, 2 trigeminal schwannomas, and 1 brainstem glioma. Presenting symptoms were dependent on extent of brainstem compression and involvement of surrounding cranial nerves. The symptoms are broken down as follows: hydrocephalus, one; balance disturbance, three; diplopia, five; trigeminal neuralgia, two; hemifacial numbness, one; seizures, one; expressive aphasia, one; and hearing loss, two. Of the 16 patients in this study, one patient needed postoperative care in a skilled nursing facility. Postoperative facial nerve weakness was not experienced in any patient. One patient developed a transient cerebrospinal fluid leak that resolved spontaneously. One patient developed a pseudomeningocele secondary to postoperative hydrocephalus. This was corrected with wound exploration and placement of a ventricular peritoneal shunt. Hearing was not maintained in one patient. Two patients developed new fourth nerve paresis and two patients developed new sixth nerve palsies. There were no postoperative infections and no deaths. The extended middle cranial fossa approach provides excellent access and exposure to tumors in the anterior cerebellopontine angle and petroclival junction. The approach allows more direct access to the area anterior to the internal auditory canal. The key to the approach is adequate bone removal of the petrous apex to provide exposure down to the inferior petrosal sinus and anteriorly to Meckel's cave and the petroclival junction. Extradural elevation of the temporal lobe with suitable brain relaxation minimizes postoperative complications.