Emanuele Piccioni

Encapsulation of micropropagated buds of six woody species

Regrowth after encapsulation in a sodium alginate matrix of micropropagated buds from six different in vitro proliferated woody species was evaluated. Actinidia deliciosa Liang & Ferguson (kiwifruit), Betula pendula Roth (birch), Crataegus oxyacantha L. (hawthorn), Malus spp. (apple), Rubus spp. (blackberry) and Rubus idaeus L. (raspberry) propagated in vitro were used as bud sources. Encapsulation with sodium alginate and subsequent regrowth on nutrient rich medium was compared to encapsulation with nutrient-enriched alginate capsules followed by regrowth on nutrientless medium. Apical and sub-apical buds of Malus (rootstock ‘M. 27’ and cultivar ‘Starkspur Red’) were also compared for encapsulation and regrowth ability. All species showed a regrowth after encapsulation, but only if cultured on enriched media. ‘M.27’ apical and sub-apical buds showed different regrowth ability after encapsulation with sodium alginate. Applicability of encapsulation of single micropropagated tree buds is discussed.

Plantlets from encapsulated micropropagated buds of M.26 apple rootstock

In order to be considered usable as synthetic seeds, encapsulated explants sown underin vitro orex vitro conditions must be able to produce whole plantlets. Ninety percent of non-encapsulated M.26 apple rootstock single nodes produced a plantlet (i.e., a well-formed shoot with a root system) after 30 days of culturein vitro if the explants were previously given a 24-hour treatment with 24.6 µM IBA and 15 g 1−1 sucrose in darkness. In contrast, when the single nodes were encapsulated in a calcium-sodium alginate bead immediately after the same treatment only 10% of the encapsulated explants formed a plantlet. Addition of growth regulators to the artificial endosperm and culture of the single nodes for root primordia initiation for 3, 6 or 9 days in darkness before encapsulation allowed production of 58%, 60% and 66% of plantlets, respectively.

Micropropagation and synthetic seed in M.26 apple rootstock (II): A new protocol for production of encapsulated differentiating propagules

Synthetic seed technology is an alternative to traditional micropropagation for production and delivery of cloned plantlets. Several aspects of the technique are still underdeveloped and hinder its commercial application. One of these aspects is the high hand labor requirements and costly procedures for the production of encapsulated explants. Direct organogenesis is an efficient shoot regeneration method and uninodal explants can be used for encapsulated synseed production. In this paper, we compare the performance of encapsulated organogenetic explants of M.26 apple rootstock that were prepared by hand and mechanical manipulation. Conversion of synseed into plantlets was 25% from encapsulated hand-cut uninodal microcuttings and 11% from machine-ground explants. The results demonstrate that synthetic seeds of M.26 apple rootstock can be produced through organogenesis from machine processed explants followed by root induction and encapsulation of differentiating propagules.

Micropropagation and preparation of synthetic seed in M.26 apple rootstock I: Attempts towards saving labor in the production of adventitious shoot tips suitable for encapsulation

In order to achieve a time and hand-labor saving procedure for the use of direct organogenesis in the production of shoot tips suitable for encapsulation, a set of experiments aimed at the gradual reduction in the accuracy of selection, hand and machine excision of the explants (leaves and whole shoot clusters) was attempted. Vegetative performance of the regenerated shoots was evaluated and encapsulation and subsequent regrowth of adventitious shoot tips was performed. The research provided useful information to devise a mechanical protocol for the production of synthetic seed through encapsulation of differentiating propagules (tissue fragments with shoot primordia) in woody species.

Rooting Induction in Encapsulated Buds of M.26 Apple Rootstock for Synthetic Seed

In 1993, Redenbaugh reported that the term “synthetic seed” (synseed) should be referred only to an encapsulated somatic embryo. In more recent years, synthetic seeds were defined as artificially encapsulated somatic embryos, shoots or other vitro-derived tissues that can be used for sowing under in vitro or ex vitro conditions (Aitken-Christie et al., 1995). It seems logical, therefore, that the terminology that was initially set up for somatic embryo synthetic seeds be now used for any kind of encapsulated expiant. The term “conversion” was explained as growth and development of both shoot and root systems, with minimal swellings, callus production, etc. In one word, “conversion” expresses the production of a green plant with a normal phenotype from a synthetic seed (Redenbaugh et al., 1988; Redenbaugh, 1993). When the above described criteria are met, it seems justified that the term “conversion” can be reasonably used to describe the development of a full plantlet from any synseed, either made from a bipolar (somatic embryo) or an unipolar explant. Talking about synseeds, there are other terms that should instead be avoided, such as “germination”, which is proper of the real seed, or “plantlet formation”, which can generally be related to any way of producing a small rooted plant from micropropagated units (Debergh and Read, 1991). Furthermore, the term “regrowth” should be used to indicate any other vegetative act different from conversion that is performed by an encapsulated propagule after sowing, such as rooting or sprouting or emission of a leaf, etc.

Numerical and Experimental Methods for Wake Flow Analysis in Complex Terrain

Assessment and interpretation of the quality of wind farms power output is a non-trivial task, which poses at least three main challenges: reliable comprehension of free wind flow, which is stretched to the limit on very complex terrains, realistic model of how wake interactions resemble on the wind flow, awareness of the consequences on turbine control systems, including alignment patterns to the wind and, consequently, power output. The present work deals with an onshore wind farm in southern Italy, which has been a test case of IEA- Task 31 Wakebench project: 17 turbines, with 2.3 MW of rated power each, are sited on a very complex terrain. A cluster of machines is investigated through numerical and experimental methods: CFD is employed for simulating wind fields and power extraction, as well as wakes, are estimated through the Actuator Disc model. SCADA data mining techniques are employed for comparison between models and actual performances. The simulations are performed both on the real terrain and on flat terrain, in order to disentangle the effects of complex flow and wake effects. Attention is devoted to comparison between actual alignment patterns of the cluster of turbines and predicted flow deviation.

Wind Power Forecasting techniques in complex terrain: ANN vs. ANN-CFD hybrid approach

Due to technology developments, renewable energies are becoming competitive against fossil sources and the number of wind farms is growing, which have to be integrated into power grids. Therefore, accurate power forecast is needed and often operators are charged with penalties in case of imbalance. Yet, wind is a stochastic and very local phenomenon, and therefore hard to predict. It has a high variability in space and time and wind power forecast is challenging. Statistical methods, as Artificial Neural Networks (ANN), are often employed for power forecasting, but they have some shortcomings: they require data sets over several years and are not able to capture tails of wind power distributions. In this work a pure ANN power forecast is compared against a hybrid method, based on the combination of ANN and a physical method using computational fluid dynamics (CFD). The validation case is a wind farm sited in southern Italy in a very complex terrain, with a wide spread turbine layout.