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Premise: The timing and pattern of a plant's flowering can have important consequences for reproductive success. Variation in flowering phenology may influence the number of prospective mates, the risk of mating with lower quality individuals, and the likelihood of self-pollination. Here we use a common garden experiment to explore within- and among-population variation in phenology. Our work provides new insights into how flowering phenology shapes mating opportunity and flowering synchrony in a self-compatible perennial., Methods: To quantify variation in flowering phenology we raised progeny from nine populations of Mimulus ringens in a common garden. For each individual, we measured phenological traits including age at flowering onset, daily floral display size, total flower number, and flowering synchrony with other members of the population, and related these traits to mating opportunity. We also tested how individual flowering schedules influence the magnitude of synchrony., Results: Flowering phenology and synchrony varied substantially within and among populations. From day to day, plants often oscillated between large and small daily floral displays. Additionally, flowering schedules of individual plants strongly influenced flowering synchrony and, along with the number of flowering days, markedly affected plants' mating opportunity., Conclusions: Phenological traits such as flowering synchrony can affect the quantity of mating opportunities and may be important targets of natural selection. Our results highlight the need for studies that quantify flowering patterns of individuals as well as populations., (© 2023 Botanical Society of America.)

Background: We are investigating the potential of robotics-assisted treadmill technology as a mode of exercise in people with spinal cord injury (SCI). People with incomplete SCI can actively contribute to this form of exercise, but in the clinical setting they often walk passively in the system. It is not known whether in doing so they are meeting the recommended guidelines for increasing cardiopulmonary fitness., Objective: The aims of this study were twofold: to characterise the intensity of passive walking during robotics-assisted treadmill exercise (RATE) in incomplete SCI; and to determine if this intensity meets the recommended guidelines for cardiopulmonary training in this population., Methods: 10 subjects with incomplete SCI twice performed an exercise test on a robotics-assisted treadmill. The test comprised a period of passive walking and a ramp phase to the limit of tolerance. Oxygen uptake VO(2) heart rate (HR) were continuously measured., Results: VO(2) during passive exercise was on average 1.4 times higher than resting VO(2R), but this was only 29% of peak VO(2) (VO(2 peak))(range 16-43%). Relative to rest, passive VO(2) (VO(2P) was only 12% of VO(2 peak). HR did not increase from rest to passive walking (81 ± 10 bpm to 81 ± 13 bpm respectively). The HR associated with passive walking was on average 50% of peak HR (HR(peak)) (161 ± 13 bpm). Test-retest reliability was moderate for VO(2R) (R=0.62) and resting HR (HR(R)) (R=0.68), high for VO(2P) (R=0.81), passive HR (HR(P)) (R=0.87) and HR(peak) (R=0.88), and very high (R=0.95) for VO(2 peak). Only HR(p) differed significantly between tests (p=0.029)., Conclusions: The intensity of passive walking during RATE is low and is insufficient to increase cardiopulmonary fitness in people with SCI. Subjects must actively contribute to the exercise in order to achieve the recommended training intensity.

We describe the use of peripheral Quantitative Computed Tomography (pQCT) to identify musculoskeletal responses to partial body-weight supported treadmill training (BWSTT) in incomplete spinal cord injury (SCI). Long-term health consequences of SCI include extensive muscle atrophy, severe bone loss and an increased fracture risk in the affected limbs, mostly at both tibial epiphyses and the distal femoral epiphysis. Regular treadmill training may slow or reverse bone loss by recruiting available lower-limb musculature and loading the leg bones dynamically. The potential for detailed analysis of musculoskeletal changes using pQCT is illustrated with a single case study (14.5 years post-SCI), who completed seven months of partial BWSTT. Pre- and post-training lower-limb pQCT scans were taken to quantify changes in trabecular bone, cortical bone, and soft-tissue. Trabecular bone mineral density increased by 5% (right) and 20% (left) in the distal tibia. Changes in proximal tibia and distal femur were negligible. Increases in muscle cross-sectional area were 6% (right) and 12% (left) in the lower leg, 7% (right) and 5% (left) in the thigh. We suggest that treadmill training may lead to positive musculoskeletal adaptations at clinically-relevant sites. Such changes can be measured in detail using pQCT.

Body weight supported (BWS) treadmill exercise could potentially improve the cardiopulmonary fitness of those with an incomplete spinal cord injury (SCI). Despite this, methods for estimating key cardiopulmonary performance parameters have not been investigated. We investigated whether new exercise test protocols for BWS treadmill exercise in incomplete SCI enable accurate determination of key cardiopulmonary performance parameters and examined how these parameters change with training. Two subjects with incomplete SCI carried out 20 weeks of BWS treadmill training (BWSTT). They performed an incremental exercise test (IET) and constant load step exercise test (SET) at baseline and 4-week intervals. After training, peak work rate had increased from 1.41 to 9.37 W in subject A and from 6.22 to 43.99 W in subject B. Peak oxygen uptake changed in subject A from 8.23 to 10.19 ml.kg-1.min-1 and from 13.84 to 13.91 ml.kg-1.min-1 in subject B. Dynamic O2 cost decreased from 115 to 29.03 ml.min-1.W-1 (subject A) and from 66.57 to 4.52 ml.min-1. W-1 (subject B). Gas exchange thresholds could not be identified from the IETs. VO2 kinetics could be identified during only 2 of subject B's SETs. Accurate estimation of key cardiopulmonary performance parameters was limited. The new protocols have the potential to characterise cardiopulmonary status and monitor adaptations to training interventions, but require testing with a larger subject cohort.