Intraspecific Variation for Leaf Physiological and Root Morphological Adaptation to Drought Stress in Alfalfa (Medicago sativa L.)

Drought stress reduces crop biomass yield and the profitability of rainfed agricultural systems. Evaluation of populations or accessions adapted to diverse geographical and agro-climatic environments sheds light on beneficial plant responses to enhance and optimize yield in resource-limited environments. This study used the morphological and physiological characteristics of leaves and roots from two different alfalfa subspecies during progressive drought stress imposed on controlled and field conditions. Two different soils (Experiments 1 and 2) imposed water stress at different stress intensities and crop stages in the controlled environment. Algorithm-based image analysis of leaves and root systems revealed key morphological and physiological traits associated with biomass yield under stress. The Medicago sativa subspecies (ssp.) sativa population, PI478573, had smaller leaves and maintained higher chlorophyll content (CC), leaf water potential, and osmotic potential under water stress. In contrast, M. sativa ssp. varia, PI502521, had larger leaves, a robust root system, and more biomass yield. In the field study, an unmanned aerial vehicle survey revealed PI502521 to have a higher normalized difference vegetation index (vegetation cover and plant health characteristics) throughout the cropping season, whereas PI478573 values were low during the hot summer and yielded low biomass in both irrigated and rainfed treatments. RhizoVision Explorer image analysis of excavated roots revealed a smaller diameter and a narrow root angle as target traits to increase alfalfa biomass yield irrespective of water availability. Root architectural traits such as network area, solidity, volume, surface area, and maximum radius exhibited significant variation at the genotype level only under limited water availability. Different drought-adaptive strategies identified across subspecies populations will benefit the plant under varying levels of water limitation and facilitate the development of alfalfa cultivars suitable across a broad range of growing conditions. The alleles from both subspecies will enable the development of drought-tolerant alfalfa with enhanced productivity under limited water availability.

Decompression for cervical disc herniation using the full-endoscopic anterior technique

OBJECTIVE

Resection of a cervical disc herniation using a full-endoscopic technique with an anterior approach.

INDICATION

Fresh disc herniation with monoradicular symptoms in the upper extremity.

CONTRAINDICATIONS

Pure neck pain, cervical myelopathy, older and calcified disc herniations, higher grade of instability and deformity.

SURGICAL TECHNIQUE

Introduction of a guidewire and dilatator to a cervical disc using an anterior approach. Under full-endoscopic view, preparation of the posterior parts of the annulus, opening of the annulus and posterior longitudinal ligament and resection of the herniated fragment from the epidural space.

POSTOPERATIVE MANAGEMENT

Immediate mobilisation, isometric/coordinative exercises, functional exercises from week 3, building up strength from week 6.

RESULTS

A total of 120 patients were operated using the full-endoscopic or microsurgically assisted technique and were followed up for 24 months. Significant improvement was achieved in both groups. The group of full-endoscopic operated patients returned to work significantly earlier and 89% of all patients would undergo the operation again.

A New full-endoscopic technique for the interlaminar operation of lumbar disc herniations using 6-mm endoscopes: prospective 2-year results of 331 patients

Even with good results, conventional disc operations may result in consecutive damage due to traumatisation. Endoscopic techniques have become the standard in many areas because of the advantages they offer in surgical technique and in rehabilitation. The transforaminal operation is the most common full-endoscopic procedure in surgery of the lumbar spine. It is frequently necessary to reach the spinal canal directly in order to achieve sufficient resection of lumbar disc herniations. Even in using a lateral approach, the authors recognise the clear limitations of the transforaminal procedure. The objective of this prospective study was to examine the technical possibility of a full-endoscopic interlaminar access. The focus was on questions of sufficient decompression, as well as advantages and disadvantages of the minimally invasive procedure. 331 patients were followed for 2 years. The results show that 82 % reported no longer having leg pain, and 13 % had only occasional pain. The decompression results are equivalent to those of conventional procedures. Traumatisation of both the access pathway and the spinal canal structures was reduced. Epidural scarring was minimised. The recurrence rate was 2.4 %. No serious surgical complications were observed. The authors view the technique described, which offers the advantage of a truly minimally invasive procedure, as a sufficient and safe alternative to conventional procedures, when the appropriate indication criteria are heeded. There are technical problems because of the small instruments. In conjunction with the transforaminal procedure, this is an expansion of the spectrum for full-endoscopic surgery of lumbar disc herniations.

[Spinal cord stimulation (SCS) using an 8-pole electrode and double-electrode system as minimally invasive therapy of the post-discotomy and post-fusion syndrome--prospective study results in 34 patients]

AIM

Therapy of a pronounced post-discotomy (PDS) and post-fusion syndrome (PFS) is often unsatisfactory because of the complexity and multifactorial pain genesis. If surgical interventions cannot promise relief and if the entire interdisciplinary spectrum of conservative treatment measures is inadequate, the area of neuromodulative procedures offers spinal cord stimulation (SCS). The objective of this study was to examine the therapeutic possibilities of SCS using an 8-pole electrode and double electrode system in PDS and PFS with extensive back-leg pain areas.

METHOD

An appropriate SCS system was implanted in 34 patients with PDS and PFS. Follow-up examinations were made prospectively over a period of 24 months using general criteria and psychometric test measuring instruments validated for German-language use.

RESULTS

An 8-pole double electrode system was implanted 23 times, a single electrode sufficed in 11 cases. The area of pain was covered in all patients. This required special technical capabilities of the SCS system. The results remained constant over 24 months. The morphine dose could be reduced by at least 50 %. All measuring instruments confirmed a clear reduction in pain and improvement in quality of life as a result of SCS implantation.

CONCLUSION

The SCS is an minimally invasive surgical procedure which can enlarge the therapeutical possibilities of pronounced PDS and PFS resistant to other modes of treatment. Special technical possibilities of parameter setting are required to cover the pain areas.