Study of the Influence of Abiotic and Biotic Stress Factors on Horticultural Plants

We would like to provide the scientists a set of studies entitled "Study of the Influence of Abiotic and Biotic Stress Factors on Horticultural Plants". The reprint book contains 12 papers about the influence of the stress factors on the plant growth and soil parameters. Authors descripted the impact of the biotic and abiotic stress factors (i.e., high, and low temperature, salt, inorganic pollutants such as salts, heavy metals, phosphite, as well as irrigation) on the physiological, biochemical, and anatomical changes occurring in the plants at the cellular, tissue, organ, and whole plant level. The subject of these studies were different plant species, i.e., watermelon, lettuce, kale, potato, grapevine, hops, orchid, strawberry, and boxwood. The ideas of the papers can be divided into five topics: (1) achieving better quality of plant material for food production by changes made in the growth conditions, metabolic and genetic modifications; (2) increasing the plant resistance to environmental stresses by application of exogenous compounds of different chemical character; (3) reducing plant stress caused by anthropogenic activity applying nonmodified and genetically modified plants; (4) mitigating drought stress by irrigation; and 5) the positive effect of plant growth-promoting microorganisms on horticulture plants performance during drought stress

Mejora de la productividad del agua y calidad de la cosecha en uva de mesa cv. ‘Crimson Seedless’

Mención Europeo / Mención Internacional: Concedido[SPA] La investigación de la tesis doctoral en curso se ocupa de la evaluación de la respuestas agronómicas y fisiológicas de madura la uva de mesa madura cv. 'Carmesí Seedless 'a secado parcial de la zona raíz (PRD) y el riego deficitario controlado (RDC) con respecto a otros tratamientos de riego que recibieron diferentes cantidades de agua aplicada. Con este fin, se establecieron cuatro tratamientos de riego: (i) Control, que recibe el 110% de la evapotranspiración del cultivo estándar, ETC, a lo largo toda la estación de crecimiento, siguiendo los criterios de la granja comercial; (ii) RDI tratamiento, regadío similar a los niveles de control durante la pre-envero y en el 50% de la misma durante post pinta (considerado el período no crítico); (iii) PRD tratamiento, regado de una manera similar a la IDI pero alternando (cada 10-14 días) las partes secas y húmedas de la zona radicular, dependiendo de déficit de agua con respecto a capacidad de campo; y (iv) un tratamiento de riego null (NI), que sólo recibió la precipitación natural y riego suplementario ocasional cuando el mediodía el potencial hídrico del tallo (ψs) superó -1.2 MPa. Para establecer ecuaciones de referencia Se utilizó otro tratamiento de riego completo (110-115% ETc). Además, el resultados se extrapolaron a un experimento en macetas con el fin de determinar la el comportamiento fisiológico de este cultivar, bajo condiciones controladas en una invernadero.[ENG] The research of the current PhD Thesis deals with the evaluation of the agronomic and physiological responses of mature table grapes cv. ‘Crimson Seedless’ to partial root-zone drying (PRD) and regulated deficit irrigation (RDI) with respect to other irrigation treatments that received different amounts of water applied. To this end, four irrigation treatments were established: (i) Control, receiving 110 % of crop standard evapotranspiration, ETC, throughout the whole growing season following the criteria by the commercial farm; (ii) RDI treatment, irrigated similar to Control levels during pre-veraison and at 50% of the same during post-veraison (considered the non-critical period); (iii) PRD treatment, irrigated in a similar way to RDI but alternating (every 10-14 days) the dry and wet sides of the root-zone, depending on water deficit with respect to field capacity; and (iv) a null irrigation treatment (NI) which only received natural precipitation and occasional supplementary irrigation when the midday stem water potential (ψs) exceeded -1.2 MPa. To establish reference equations another full irrigation treatment (110-115% ETc) was used. Furthermore, the results were extrapolated to a pot experiment in order to determine the physiological behavior of this cultivar, under controlled conditions in a greenhouse. Chapter I analysed the yield response and chemical quality to long-term deficit irrigation (DI) strategies. No significant differences were found between PRD and RDI with respect to well-watered vines irrigated according to ETc, thus the application of a greater amount of water was not essential for plant behavior and berry development in ‘Crimson Seedless’ table grapes. Both PRD and RDI treatments supposed a water saving of 35% without compromising total yield and its components. Only NI (which received 72% less water than Control) led to a reduction in yield and the weight of clusters/berries compared with the other irrigated counterparts. Water use efficiency was also increased in all DI treatments as many water restrictions were assessed. Regarding chemical berry quality, all deficit irrigation treatments increased berry coloration (evaluated subjectively and objectively) which is considered the main issue of this variety for its marketability. Despite the fact that RDI and PRD received the same amount of annual water applied, PRD induced a greater accumulation of skin anthocyanins, resveratrol and antioxidant capacity. Although PRD did not show significant changes in yield response with respect to RDI, the fact that PRD increased the main bioactive compounds analysed that are beneficial to health, underlined the feasibility of the implementation of this strategy by growers. Chapter II focused on the long-term impact of DI strategies on physical berry quality, with particular attention to the berry firmness, since it is one of the most important characteristics in order to be marketed and for consumer acceptance. Moreover, the storage performance to ascertain the potential shelf-life of this cultivar was reported. RDI and PRD did not noticeably affect physical berry quality after cold storage while the subsequent shelf-life period tended to minimise the difference found at harvest or at the end of cold storage. Furthermore, NI treatment showed the worst sensory scores post-harvest and the most dehydrated clusters and lower berry size. In fact, sensory results were similar in RDI and PRD, which provided grapes that were more acceptable to consumers than well-irrigated vines, mainly due to lower stem browning and higher berry coloration. Remarkably, PRD registered the highest berry shattering, which was correlated with the lower concentration of ABAxylem induced by the grower’s strategy. Thus, the results obtained in Chapters I and II indicate that it is possible to decrease irrigation by applying RDI and PRD to ‘Crimson Seedless’ table grapes without adversely affecting yield and the physicochemical berry quality. The physiological response and vegetative growth to DI strategies were described in Chapter III. The analysis of the physiological fluxes (net CO2 assimilation, ACO2 and transpiration rate, E) and their characteristic attributes (stomatal conductance, gs) determined at leaf scale, under saturating-light conditions, showed a water stress response in accordance to the water stress severity imposed, regardless of irrigation strategy. Comparing post-veraison strategies, PRD induced higher plant and soil water deficit levels than RDI. Nevertheless, PRD neither significantly reduced gs nor increased ABAxylem against expectations. These results suggest a greater root development and root density from PRD with respect to RDI for water uptake. As expected, vegetative parameters were adversely affected by the severe deficit reached in NI, while the leaf area index was also modified by PRD. Principal components analysis (PCA) results showed that inter-annual differences detected between irrigation treatments were higher than those observed between phenological periods, especially when RDI and PRD were compared. Furthermore, maximum daily shrinkage (MDS) was the best plant-water status indicator to ascertain irrigation differences before veraison, whereas other conventional plant water status indicators (such as water potential and transpiration rate, E) might be considered for irrigation scheduling during post-veraison. Different reference lines appeared in Chapter IV from plant water status indicators such as MDS and ψs indicators were obtained during pre and post-veraison periods, respectively, for irrigation scheduling in well-irrigated table grapes cv. ‘Crimson Seedless’. In this sense, MDS and ψs showed better adjustment with mean temperature (Tm) during pre-veraison, while after veraison reference crop evapotranspiration (ET0) and vapour pressure deficit can also be used. The correlation coefficients in MDS decrease during post-veraison due to changes of stem transpiration, the presence of sugar-demanding sinks and the accumulated ABAxylem. Besides this, under commercial conditions, water savings with respect to conventional scheduling based on ETc were achieved when the irrigation scheduling was done using SIMDS around unity (in pre-veraison) and maintaining ψs as a threshold value in well-watered vines (in post-veraison). Moreover, in this Chapter we also observed that some standard cultural practices such as girdling and the collocation of hail mesh to prevent torrential rainfalls might also modify vine water status. From a physiological point of view, the results obtained were extrapolated to a pot experiment in Chapter V. Table grapes showed a substantial loss of photosynthetic capacity as the season progressed both growing in the field (as shown in Chapter III) and in a pot experiment (Chapter V). Crimson Seedless displayed different responses to DI strategies, depending on the diurnal course. At predawn (t1) and early morning (t2), the cultivar showed near-anisohydric behavior, through a less effective stomatal control of drought, whereas at midday (t3), the behavior was near-isohydric. In addition to this, water stress conditions induce avoidance mechanisms to drought, such as stomatal closure, partial defoliation and a reduction in leaf insertion angle. Analysis of the vegetative response does not indicate that PRD vines respond differently, or present a clear distinct adaptive mechanism to water stress with respect to RDI vines. In fact, pruning dry weight was only affected by severe water deficit (NI).Universidad Politécnica de CartagenaPrograma Oficial de Doctorado en Técnicas Avanzadas en Investigación y Desarrollo Agrario y Alimentari

Compiler Estimation of Parallelism and Communication for Quantum Computation

Quantum computing promises to speed up scientific and computationally intensive operations. However, the power of quantum computing is limited by the relatively small window of time where the quantum state and be maintained (coherent). To achieve maximum efficiency, not merely to keep this state coherent but to increase computational productivity, maximizing the parallelism of the system is important. The architectural model that is explored here attempts to exploit the relatively small number of operations that are actually performed within a quantum computer to maximize fine-grained, data level parallelism, as opposed to the more common coarse-grained, task level parallelism. This model represents a Multi-SIMD processor design, where multiple SIMD cores are used to boost data level parallelism, but allows for limited task indepence.The purpose of this work is to explore the effectiveness of parallel processing in a Multi-SIMD quantum architecture. It examines the ability to speedup computation using a combination of parallel processing scheduling and communication awareness, showing up to 7.8X speedup. This information is then used to extract theoretical requirements for bandwidth (>8000 qubits/cycle peak) and throughput (3 qubits/cycle sustained). This research leverages the ScaffCC compiler toolchain [26], which provides a logical-level (i.e., implicitly error-corrected) quantum assembly output as the input to be scheduled and analyzed

Auto-tuning Interactive Ray Tracing using an Analytical GPU Architecture Model

This paper presents a method for auto-tuning interactive ray tracing on GPUs using a hardware model. Getting full performance from modern GPUs is a challenging task. Workloads which require a guaranteed performance over several runs must select parameters for the worst performance of all runs. Our method uses an analyti- cal GPU performance model to predict the current frame’s render- ing time using a selected set of parameters. These parameters are then optimised for a selected frame rate performance on the partic- ular GPU architecture. We use auto-tuning to determine parameters such as phong shading, shadow rays and the number of ambient oc- clusion rays. We sample a priori information about the current ren- dering load to estimate the frame workload. A GPU model is run iteratively using this information to tune rendering parameters for a target frame rate. We use the OpenCL API allowing tuning across different GPU architectures. Our auto-tuning enables the render- ing of each frame to execute in a predicted time, so a target frame rate can be achieved even with widely varying scene complexities. Using this method we can select optimal parameters for the cur- rent execution taking into account the current viewpoint and scene, achieving performance improvements over predetermined parame- ters

GPU Wavefront Splitting for Safety-Critical Systems

Graphics processing units (GPUs) are compute platforms that are ideal for highly parallel workloads due to their high degree of hardware parallelism. Parallelism offered by GPUs lends itself well to machine learning and computer vision applications, including in safety-critical systems. Safety-critical systems require a guarantee of timing predictability. Guaranteeing timing predictability means being able to statically analyze the worst-case execution time (WCET) of the GPU program. Unfortunately, existing GPUs are designed for average-case performance and are thus not designed for timing predictability. Consequently, there is potential for research effort to provide these guarantees. Prior research works have proposed several new techniques to improve performance. One such technique is wavefront splitting, which reduces the number of idle threads on the GPU and increase utilization. However, no prior work addresses the WCET of this technique. The purpose of this thesis is to develop a GPU implementation for safety-critical systems that leverages wavefront splitting and to enable analysis of the WCET in such an implementation

Accelerating The Discontinuous Galerkin Cell-Vertex Scheme (Dg-Cvs) Solver On Cpu-Gpu Heterogeneous Systems

Dg-Cvs (Discontinuous Galerkin Cell-Vertex Scheme) is an efficient, accurate and robust numerical solver for general hyperbolic conservation laws. It can solve a broad range of conservation laws such as the shallow water equation and Magnetohydrodynamics equations. Dg-Cvs is a Riemann-Solver-free high order space-time method for arbitrary space conservation laws. It fuses the discontinuous Galerkin (dg) method and the conservation element/solution element (ce/se) method to take advantage of the best features of both methods. Thanks to the ce/se method, the time derivative of the solution is treated as an independent unknown, which is amendable to gpu\u27s parallel execution. In this thesis, we use a cpu-gpu heterogeneous processor to accelerate Dg-Cvs to demonstrate that complex scientific applications can benefit from a heterogeneous computing system. There are challenges that such scientific program poses on the gpu architecture such as thread divergence and low kernel occupancy. We developed optimizations to address these concerns. Our proposed optimizations include thread remapping to minimize thread divergence and register pressure reduction to increase kernel occupancy. Our experiment results show that Dg-Cvs on gpu outperforms cpu by up to 57\% before optimization and 145\% afterwards. We also use Dg-Cvs as a real world application to explore the possibility of using shared virtual memory (svm) for tighter collaboration between cpu and gpu. However, svm did not help improve the performance due to the overhead of address translation and atomic operations. We developed a microbenchmark to better understand the performance impact of svm