Root anatomical traits contribute to deeper rooting of maize under compacted field conditions

© The Author(s) 2020. To better understand the role of root anatomy in regulating plant adaptation to soil mechanical impedance, 12 maize lines were evaluated in two soils with and without compaction treatments under field conditions. Penetrometer resistance was 1–2 MPa greater in the surface 30 cm of the compacted plots at a water content of 17–20% (v/v). Root thickening in response to compaction varied among genotypes and was negatively associated with rooting depth at one field site under non-compacted plots. Thickening was not associated with rooting depth on compacted plots. Genotypic variation in root anatomy was related to rooting depth. Deeper-rooting plants were associated with reduced cortical cell file number in combination with greater mid cortical cell area for node 3 roots. For node 4, roots with increased aerenchyma were deeper roots. A greater influence of anatomy on rooting depth was observed for the thinner root classes. We found no evidence that root thickening is related to deeper rooting in compacted soil; however, anatomical traits are important, especially for thinner root classes

Treatment for paediatric chronic fatigue syndrome or myalgic encephalomyelitis (CFS/ME) and comorbid depression:a systematic review

OBJECTIVES: At least 30% of young people with chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) also have symptoms of depression. This systematic review aimed to establish which treatment approaches for depression are effective and whether comorbid depression mediates outcome. SETTING: A systematic review was undertaken. The search terms were entered into MEDLINE, EMBASE, PsycInfo and the Cochrane library. PARTICIPANTS: Inclusion and exclusion criteria were applied to identify relevant papers. Inclusion criteria were children age <18, with CFS/ME, defined using CDC, NICE or Oxford criteria, and having completed a valid assessment for depression. RESULTS: 9 studies were identified which met the inclusion criteria, but none specifically tested treatments for paediatric CFS/ME with depression and none stratified outcome for those who were depressed compared with those who were not depressed. There is no consistent treatment approach for children with CFS/ME and comorbid depression, although cognitive–behavioural therapy for CFS/ME and a multicomponent inpatient programme for CFS/ME have shown some promise in reducing depressive symptoms. An antiviral medication in a small scale, retrospective, uncontrolled study suggested possible benefit. CONCLUSIONS: It is not possible to determine what treatment approaches are effective for depression in paediatric CFS/ME, nor to determine the impact of depression on the outcome of CFS/ME treatment. Young people with significant depression tend to have been excluded from previous treatment studies

“It’s personal to me”:A qualitative study of depression in young people with CFS/ME

Background: Paediatric chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) has a prevalence of 0.4–2.4% and is defined as ‘generalised disabling fatigue persisting after routine tests and investigations have failed to identify an obvious underlying cause’. One-third of young people with CFS/ME have probable depression. Little is known about why depression develops, the relationship between depression and CFS/ME, or what treatment might be helpful. Methods: We conducted nine semi-structured interviews with young people with CFS/ME (aged 13–17 years, 8/9 female) and probable depression, covering perceived causes of depression, the relationship between CFS/ME and depression, and treatment strategies. Results: Most thought CFS/ME caused depression. Many discussed a cyclical relationship: low mood made CFS/ME worse. A sense of loss was common. CFS/ME restricted activities participants valued and changed systemic structures, causing depression. There was no single helpful treatment approach. Individualised approaches using combinations of cognitive behavioural therapy (CBT), medication, activity management and other strategies were described. Conclusion: This study suggests that depression may be secondary to CFS/ME in young people because of the impact of CFS/ME on quality of life. Clinicians treating young people with CFS/ME need to consider strategies to prevent development of depression, and research is needed into approaches that are effective in treating CFS/ME with co-morbid depression. </jats:sec

In situ root identification through blade penetrometer testing – Part 2:field testing

The spatial distribution, depths and diameters of roots in soil are difficult to quantify but important to know when reinforcement of a rooted slope or the stability of a plant is to be assessed. Previous work has shown that roots can be detected from the depth–resistance trace measured using a penetrometer with an adapted blade-shaped tip. Theoretical models exist to predict both forces and root displacements associated with root failure in either bending or tension. However, these studies were performed in dry sand under laboratory conditions, using acrylonitrile butadiene styrene root analogues rather than real roots. In this paper blade penetrometer field testing on two forested field sites, with Sitka spruce and pedunculate oak in sandy silt and clayey silt, respectively, is used to evaluate models under field conditions. Root breakages could be detected from blade penetrometer depth–resistance traces and using complementary acoustic measurements. Predictions of additional penetrometer resistance at root failure were more accurate than the displacement predictions. An analytical cable model, assuming roots are flexible and fail in tension, provided the best predictions for Sitka roots, whereas thick oak roots were better predicted assuming bending failure. These matched the modes of failure observed in three-point bending tests of the root material in each case. The presence of significant amounts of gravel made it sometimes difficult to distinguish between hitting a root or a stone. The root diameter could be predicted when root strength and stiffness, and soil penetrometer resistance were known and the right interpretative model was selected. Estimates based on peak force were more accurate than those based on root displacement. This measurement procedure is therefore a potentially valuable tool to quantify the spatial distribution of roots and their reinforcement potential in the field. </jats:p

The therapeutic relationship in Cognitive Behaviour Therapy with depressed adolescents: a qualitative study of good-outcome cases

Objectives. This paper aimed to explore client experiences of the therapeutic relationship among adolescents with good outcomes after receiving Cognitive Behaviour Therapy (CBT) for moderate to severe depression. Design. This was a qualitative study employing Interpretative Phenomenological Analysis (IPA). Methods. As part of a randomized clinical trial, 77 adolescents with moderate to severe depression were interviewed using a semi-structured interview, which was audiorecorded. Five of these interviews, with adolescents aged 14–18 years who completed CBT and had good outcomes, were purposively sampled and analysed using IPA. Results. The findings indicated that a positive therapeutic relationship was fostered with therapists who respected the adolescents’ autonomy and sense of individuality, while offering experiences of emotional closeness and connection. This was achieved by balancing the dual roles of being ‘friendly’ and affable, with being a ‘professional expert’ thereby embodying a collaborative and egalitarian approach. Conclusions. The therapeutic relationship in CBT can help to motivate adolescents to engage with cognitively and emotionally challenging tasks. By providing an understanding of what helps and hinders the development of a positive therapeutic relationship, the current findings offer important insight into how therapists can foster positive relationships with depressed adolescents. This knowledge will make it more likely that adolescents will engage in the treatment process and in turn experience greater therapeutic gains

Effect of root spacing on interpretation of blade penetration tests-full-scale physical modelling

The spatial distribution of plant roots is an important parameter when the stability of vegetated slopes is to be assessed. Previous studies in both laboratory and field conditions have shown that a penetrometer adapted with a blade-shaped tip can be used to detect roots from sudden drops in penetrometer resistance. Such drops can be related to root properties including diameter, stiffness and strength using simpleWinkler foundation models, thereby providing a field instrument for rapid quantification of root properties and distribution. While this approach has proved useful for measuring single widely-spaced roots, it has not previously been determined how the penetrometer response changes as a result of roots being in close proximity. Therefore in this study 1-g physical modelling (at 1:1 scale) was conducted to study the effect of vertical root spacing using horizontal, straight 3D-printed root analogues. Results showthatwhen roots are closely spaced, there is significant interaction between them, resulting in higher apparent root displacements to failure and an increased amount of energy being dissipated. This preliminary work shows that the interpretive models used to analyse the penetrometer trace require further development to account for root-soil-root interactions in densely rooted soil.</p

Comparison of new <i>in situ </i>root-reinforcement measuring devices to existing techniques

Mechanical root-reinforcement is difficult to quantify. Existing in-situ methods are cumbersome, while modelling requires parameters which are difficult to acquire. In this paper, two new in-situ measurement devices are introduced ('cork screw' and 'pin vane') and their performance is compared to field vane and laboratory direct shear strength measurements in fallow and rooted soil. Both new methods show a close correlation with field vane readings in fallow soil. Tests in reinforced soil show that both new methods can be installed without significant root disturbance. The simplicity of both new methods allows for practical in-situ use and both can be used to study soil stress-strain behaviour, thus addressing some major limitations in existing methodologies for characterising rooted soil.</p

In situ root identification through blade penetrometer testing – Part 1:interpretative models and laboratory testing

Root architecture and reinforcement are important parameters to measure the safety of vegetated slopes and stream banks against slope instability and erosion or to assess the stability of plants against environmental loading (e.g. windthrow of trees). However, these are difficult to measure without time-consuming sampling or counting procedures. Previous studies proposed using a penetrometer with an adapted geometry, and showed that individual root breakages could be detected as sudden drops in penetrometer resistance. However, there are no existing models to derive root properties from the measured traces. Here, several interpretative models are developed and their performance at identifying and characterising buried acrylonitrile butadiene styrene root analogues of varying diameter and architecture in sand are assessed. It was found that models, assuming the analogues broke in bending rather than tension, provided good predictions for the force–displacement behaviour. The simple analytical bending model developed here was shown to perform almost as well as more sophisticated numerical models. For all models, the predictions of additional penetrometer force required to break the root analogue were more accurate than predictions for lateral root displacement required to reach failure. The root analogue diameter and to a lesser extent the soil resistance and root angle were shown to affect the penetrometer resistance strongly. Root branching, root length and the distance between the point of load application and a root boundary (root tip or parent root) had a much smaller effect. When the root failure mechanism, root strength, root stiffness and soil resistance are known, an accurate prediction of the root diameter can be made based on the root peak resistance value identified from a blade penetration test. Penetrometer testing, a test which is easy to perform in the field, coupled with an accurate interpretative model might therefore be an effective method to rapidly quantify the spatial distribution, depths and diameters of roots. </jats:p