Impaginato 59 1. Introduction To aid summer-time thermal control in urban areas, the creation of shade above buildings and/or streets is highly important for a number of reasons. First, shade can provide protection for residents and passersby by buffering the changes in housing ther- mal conditions inside the building and/or local cli- mate on the streets during heat wave attacks, a seri- ous concern as discovered in the case of the historic, heat-related disaster in Paris in 2003 (Keller, 2013). Second, minimizing energy consumption within build- ings has become an important goal of architecture and urban planning in recent years. As a result, sever- al guidelines have been developed depending on the climatic zones, aimed at increasing solar exposure for buildings in cold climates and reducing solar expo- sure for buildings in warm climates (Okeil, 2010). Adv. Hort. Sci., 2016 30(2): 59-67 DOI: 10.13128/ahs-19130 Optical evaluation of the shading properties of climbing fern Lygodium japonicum used as a thermal buffering green wall plant A. Hara 1, H. Takaichi 1, Y. Murata 1, R. Sakata 1, Y. Hara 1, J. Iwase 2, 3, D. Comparini 1, 2, 4, T. Suzuki 1, 4,T. Kawano 1, 2, 4 (*) 1 Faculty and Graduate School of Environmental Engineering, The University of Kitakyushu, Kitakyushu, Japan. 2 LINV Kitakyushu Research Center, Kitakyushu, Japan. 3 Kyushu Institute of Technology Collaboration Center, Kitakyushu, Japan. 4 International Photosynthesis Industrialization Research Center, The University of Kitakyushu, Kitakyushu, Japan. Key words: building thermal control, environmental measurements, green roof, green wall, rooftop garden, urban agricul- ture. Abstract: Recently, thermal properties of the landscaped rooftops and walls have attracted the interest of researchers because of the potential to minimize energy consumption in urban areas and to aid summer-time thermal control. For this reason the creation of a plant-based shade for walls or above buildings is highly important. In this paper we evaluate using Lygodium japonicum, one of the many ferns and fern allies traditionally used in Japanese gardening, as a compo- nent of thermal-buffering green walls. Lygodium japonicum, the only climbing fern species in Japan, is fast-growing, adheres easily to walls and has a climbing nature. A simple thermal analysis of the sun-shading effect of Lygodium canopy suggested that local surface temperature above the ceramic tiles placed on the rooftop of a building can be buffered (lowered in daytime and maintained relatively warm at night) by the presence of leafy climbing ferns covering the tiles, possibly due to the reflection and absorbance of solar radiation. Furthermore, the presence of the plants may also slow the night-time release of heat from the building surface. Because plants installed on tall walls or on the tops of buildings are not easily accessed for manual care, we performed a real-time routine monitoring and control of plant growth status using various optical sensors that could be automated and monitored remotely for large-scale applica- tions. For this purpose, the optical properties of a L. japonicum canopy under solar incident light have been determined. In order to evaluate the natural shading and growing properties of a green canopy, the incident solar radiation spectrum (J), leaf canopy-filtered light spectrum (transmittance, T) and leaf-reflectivity spectrum (R) were measured. By reading the reflectivity spectrum, concomitant chlorophyll fluorescence signals (F) from Lygodium leaves were also detected at 760 nm, which corresponds to the O2-A Fraunhofer line. Our data suggests that the daily change in photosynthetic status (P) can be traced by monitoring the change in relative F in relation to the estimated heat loss (H) and measured J, R, and T using a series of practical equations designed to roughly estimate the gross photosynthetic response within the plant canopy. Using our equations, the photosynthetic capacity in the plant canopy structure could be simply simulated and predictable by optical sensors. (*) Corresponding author: kawanotom@kitakyu-u.ac.jp Received for publication 23 December 2015 Accepted for publication 19 February 2016 Copyright: © 2016 Author(s). This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Adv. Hort. Sci., 2016 30(2): 59-67 60 The thermal properties of greened rooftops and walls have recently been extensively documented. A study was performed to compare greened and non- greened walls with and without additional covering shade cloths using model buildings with thermal thin walls (Yamasaki et al., 2009). By quantitatively evalu- ating the cooling load reduction effect under/inside the greened roof/walls, the room temperature of the green-covered building was shown to be significantly lower due to the sun-shielding effect of plants cover- ing the building, and electrical power consumption for air conditioning was also lower in the green build- ing. According to this model, around 40 to 45% of energy could be saved in the greened building com- pared to the non-greened building. It is natural to conclude that lowering total temperature inside the model buildings is the consequence of the local tem- perature controls on the surface of the walls or roofs. As a lack of or excess water could drastically alter the growth status of the plants installed, water con- sumption by the plants needs to be understood. In addition, the rate of water consumption and air-cool- ing properties of plants have a close relationship since transpiration by plant leaves plays a key role in local heat removal. Therefore, quantitative evalua- tion of water consumption by a model wall-greening system is of great importance. Toward this purpose, simple models with net-supported vine plants (such as ivy and morning glory) have reportedly been con- ducted (Takayama et al., 2014). Like other forms of green infrastructure, green façades in which climbing plants are grown either directly against, or on support structures affixed to external building walls, have recently been gaining the attention of architects as a design feature aimed at reducing internal building temperatures, reducing building energy consumption, and facilitating urban adaptation to a warming climate (Hunter et al., 2014). Today, such vertical greenery systems (VGS) are viewed as passive tools for energy savings in buildings (Pérez et al., 2014). Accordingly, not only the lowering of building temperature, but also many economic, environmental and social benefits are associated with the use of VGS (Safikhani et al., 2014). Furthermore, various new green wall con- struction methods have been developed to date, although many of these technologies have yet to be evaluated and even to be amended, mainly due to the difficulty of maintaining the active growth and development of plants under stressful conditions such as forced adhesion by artificial supports, expo- sure to thermal stresses, lack of or excess irrigation and/or fertilization on site and on time (Tachibana et al., 2011). Reports on approaches for the greening of build- ings using self-growing plants are increasing day-by- day. For an instance, a Canadian team has designed a prefabricated piece to be used on building envelopes, interior partitions, façades or landscape enclosures, in which the vegetation is integrated within the wall construction instead of being adhered to it (Ardila et al., 2009). Accordingly, the designed system by an incorporated conduit system included the self-sup- porting, self-irrigating and self-fertilizing perfor- mance for the growing plants. An urban geographer, Gandy (2010), has explored the work of French botanist Patrick Blanc, who applies his knowledge of botany and related sciences to urban wall design with inspiration from the mur végetal (green wall) first made in 1988. Blanc intended to transform the urban sceneries into ravines or rainforests by cover- ing the streets and buildings with ferns and mosses. It is well known in Japan that, second to mosses, many members of Pteridophytes (encompassing ferns and fern allies) have been traditionally used in Japanese garden design (Kawano, 2015). As encour- aged by a French botanist, one of the authors (TK) recently propounded that the use of Japanese fern species on green walls and/or roofs is worth pursuing (Kawano, 2015). For this reason, we would like to dis- cuss the criteria for the plant components of heat buffering green walls which should also be applied to the fern species. The first criterion is the plants’ adhesion to the surfaces of walls or roofs. Among the common gar- den ferns found in Japan, members of Polypodiaceae such as Lemmaphyllum microphyllum Presl (Japanese name: Mamezuta), Lepisorus thunbergianus (Kaulf.) Ching (Japanese name: Nokishinobu), and Pyrrosia lingua (Thunb.) Farw (Japanese name: Hitotsuba) are epiphytic species often attached to trees and rocks. Therefore, these plants can be effectively used to cover walls. However, Lemmaphyllum microphyllum is often exposed to competition on the surface of rocks and walls with neighboring epiphytic higher plants such as Ficus pumila L. (Moraceae; Japanese name: Ōitabi). Therefore, we would like to empha- size that the second criterion for plant components of thermal buffering green walls is that they should be fast growing. The third criterion for green wall ferns must be an ability to not only adhere, but also climb up the poles and nets, and cover irregular walls of the greening structures. The last criterion is the heat-buffering property of the greenery components. Hara et al. - Optical evaluation of the shading properties of Lygodium japonicum 61 However, to date, studies on the influence of climb- ing plant characteristics are still very limited, and even fewer works have investigated the impact of green façade design components on thermal perfor- mance (Hunter et al., 2014). As a candidate fern species to be listed as a green wall component, Lygodium japonicum (Thunb.) Sw. (Lygodiaceae; Japanese name: Kanikusa), the only climbing fern species in Japan, is of great interest since this plant species has a fast-growing, wall adhe- sive, and climbing nature. The sun-tracking and rotat- ing movements associated with the climbing growth in two Lygodium members (L. articulatum and L. scandens) were briefly described by Charles Darwin (1875). In his book, he concluded that “As ferns differ so much in structure from phanerogamic plants, it may be worthwhile here to show that twining ferns do not differ in their habits from other twining plants”. Finally, the heat buffering property under solar radiation must be determined with L. japonicum. Through the minimal model tests described here, we attempt to demonstrate that local surface tempera- ture above ceramic roof tiles of a building can be effectively buffered, thus lowering daytime tempera- ture and maintaining relative warmth during the night, by the presence over the tiles of leafy climbing ferns, possibly due to reflection and absorbance of solar rays and prevention of the release of heat from the building surface. However, once plants are installed on tall walls or the top of buildings which are far from accessible for manual daily care, real- time routine monitoring and controls of plant growth status should be automated using various optical sensors. For this purpose, background data for opti- cal properties of a Lygodium canopy under solar inci- dent light, reflecting the thermal and growing status, have been investigated. 2. Materials and Methods Plant materials and experimental set up Lygodium japonicum is commonly known as “Japanese climbing fern”. This native fern grows very rapidly and thus often covers neighboring living trees, rocks and walls in gardens (Fig. 1). For orna- mental purposes, L. japonicum has been exported out of the country. For instance, this plant was intro- duced in 1932 in Florida, USA (Gordon and Thomas, 1997). In the Hibikino campus of the University of Kitakyushu (Wakamatsu-ku, Kitakyushu, Japan; 33˚ 53’24’’ North latitude, 130˚ 42’ 49’’ East longitude), semi-wildly propagating L. japonicum plants (Fig. 1A- E) directly exposed to sunlight were sampled, replanted in pots, and kept in the greenhouse for three days under fluorescent light to recover prior to experiments. Model set-up on building roof to measure daytime roof tile temperature with and without Lygodium leaf canopy The experimental was set up on the rooftop of a building to assess the shading properties of the Lygodium canopy (Fig. 2A). Lygodium plants were potted and placed on the building roof-top, with bunches of leaflets covering ceramic tiles on which pairs of fine thermocouples (thermal sensors) were set. We previously reported the real-time measure- ment of rapid and accurate temperature changes in the micro-environments within a plant cell culturing system (Lin et al., 2006). The real-time thermo-sens- ing units employed here have similar set-ups. The units consist of fine thermocouples (KFT-25-200-100, ANBE SMT Co., Japan), an AD/DA 8 channel converter (MR-500, Keyence, Japan), and a PC with a display (Fig. 2 B-D). Each sensory unit, calibrated immediate- Fig. 1 - The semi-wildly propagating Japanese climbing fern, Lygodium japonicum, used in this study. (A) Vegetative leaflet. (B) Reproductive leaflet. (C) Semi-wild plants sur- viving in the gaps between stones (as indicated by arrows). (D) Aggressive growth of L. japonicum winning the competition with other standing plants. (E) Climbing growth of L. japonicum on the concrete and aluminum walls, thus naturally greening the building. (F) Even though it came after, L. japonicum plants are growing on the concrete wall by rapidly covering over the pre-exist- ing vines of Ficus pumila L. Plants were found on Hibikino campus of the University of Kitakyushu, Wakamatsu-ward, Kitakyushu, Japan (A-E), and a private garden in Miyazaki Prefecture, Japan (F). Adv. Hort. Sci., 2016 30(2): 59-67 62 ly before the experiment, possesses small heat capacity, thus enabling immediate and accurate mea- surements. Solar spectra, canopy-filtered light spectra and leaf- reflectivity spectra To measure solar and leaf canopy light spectra, a CL-500A Illuminance Spectrophotometer (Konika Minolta, Tokyo, Japan), which covers the range between 360 nm and 780 nm, was used. Spectroscopic analyses of reflectivity on the surface of leaves were carried out using a portable near- infrared (NIR) field spectro-radiometer, FieldSpec HandHeld 2 (ASD Inc., Atlanta, GA, USA), designed for spectral measurements (ranging from 325 nm to 1075 nm) on site (Fig. 2E). In figure 2F and G, the fate of incident solar light illuminating plant leaves and generalized modes of energy transfer by short wave- length (blue) light and long wavelength (red) light after illumination of chlorophylls are illustrated. Based on the experimental design described here, spectroscopic data on incident light (J), reflection by leaves (R), transmittance through leaves (T), light energy captured by leaves (j) and chlorophyll fluores- cence (F) can be non-invasively and remotely moni- tored. 3. Results and Discussion Effects of Lygodium japonicum canopy on ceramic roof tile surface temperature The heat-blocking or buffering action by the leafy canopy of L. japonicum was assessed by monitoring the changes in local temperature on the surface of model ceramic tiles with and without L. japonicum coverage (Fig. 3). Comparisons were made on a cloudy day (2 October 2014) (Fig. 3, top) and a sunny day (3 October 2014) (Fig. 3, bottom). In both cases, daytime temperature was higher on the control tiles without plant canopy. Data clearly suggest that the fluctuation of temperature due to direct exposure to naturally changing solar light intensity could be buffered. Fig. 2 - Experimental set up to assess the shading properties of the Lygodium japonicum canopy on the roof of a build- ing. (A, B) L. japonicum plants set up on the roof. (C) One of the fine thermocouples placed on the ceramic tiles. (D) Composition of the monitoring units. (E) Measurement of reflection spectra on the surface of plant leaves using a portable NIR field spectro-radiome- ter. (i) PC control booth beneath the solar panels. Arrows (ii) and (iii) indicate the positions of the thermo- couples. (iv) A note PC, (v) an AD/DA 8-channel convert- er, (vi) connecting cables. (F) Fate of incident solar light illuminating plant leaves. J, incident light; R, reflection; T, transmittance; j, captured light energy; H, local heat loss; F, fluorescence; and P, photosynthesis. Optically, J, R, T, j and F can be determined. (G) Energy transfer by short wavelength (blue) light and long wavelength (red) light after illumination of chlorophylls. Fig. 3 - Assessment of the sun-shading effect of L. japonicum canopy by monitoring of the surface temperature. Typical data, recorded on 2 and 3 October 2014, are shown. Hara et al. - Optical evaluation of the shading properties of Lygodium japonicum 63 In addition to the action of the plant canopy in the daytime, the nighttime changes in local temperature were also buffered by the presence of the L. japon- icum leaves, possibly by minimizing the bulk flow of heat-removing air reaching the tile surface, and also by blocking the heat transfer out of ceramic tiles through the highly reflective nature of the leaves in the NIR region. These hypotheses will be the subject of critical experimental examination in future studies. Filtering of solar rays through Lygodium japonicum leafy canopy Solar radiation above and under the L. japonicum leafy canopy were monitored with a hand-held Spectrophotometer (Fig. 4). By subtracting the level of radiation under the canopy from that recorded above the plants, total light filtering performance by L. japonicum canopy could be calculated (Fig. 4, bot- tom). Data from two nearby experimental sites, each with its independent plant, indicated that a majority of solar radiation was filtered by the leaf canopy, possibly through absorption and reflection of light. Reflection of solar rays by Lygodium japonicum leaves Reflectivity of L. japonicum leaflet surface was measured under sunlight (Fig. 5) (3 October 2014). Due to the presence of chlorophylls, there was always a pair of valleys of reflectivity in the blue and red regions (in the range below 450 nm and around 660 nm), which correspond to the absorbance by chlorophyll a and its related metabolites (Kawano et al., 1999). In the range of visible light, green-colored light (peaking at around 550 nm) was most highly reflected as expected by the presence of chlorophylls in the leaves. Since green light was also the major light component of the under-canopy radiation (Fig. 4), absorption of green light by plant pigments was shown to be negligible. In the NIR region, a high rate of solar radiation was reflected upwards (Fig. 5), suggesting that the decrease in NIR radiation below the plant canopy is largely due to reflection. A steep increase in reflectiv- ity spanning from the red region to NIR region repre- sents the so-called “red edge” of reflection. This is a phenomenon commonly observed in various green Fig. 4 - Spectrometric analysis of solar radiation and its filtering by L. japonicum canopy. Typical data, recorded on 3 October 2014, are shown. Fig. 5 - Analysis of leaf reflectivity using the leaves of L. japon- icum plants covering ceramic roof tiles. (A) Typical reflectance spectra from L. japonicum leaves recorded at 9:00, 12:00, 15:00 and 18:00 on 3 October 2014 are shown. (B) An example of processed reflectance spec- trum. Relative signal intensity was determined after the first order differentiation of the spectral data. (C) Changes in the normalized chlorophyll fluorescence sig- nal. Signals corresponding to reflectance in the green and red-to-NIR regions are labeled as “Green reflection” and “Red edge”, respectively. Chlorophyll-dependent fluorescence signals detected at 760 nm and 679 nm, corresponding to O2-A and O2-B Fraunhofer lines, respectively, are labeled. Adv. Hort. Sci., 2016 30(2): 59-67 64 leafy plants, suggesting that most green plant canopies are capable of creating shade, minimizing the NIR radiation allowed to reach ground level, thus blocking the heating radiation to reach beneath the leaves. In this context, a L. japonicum canopy fulfills one of the key criteria as a thermal buffering plant canopy. Detection of chlorophyll fluorescence signals in the reflectivity spectra At 760 nm, the wavelength corresponding to the O2-A solar Fraunhofer line (telluric absorption band) near 760 nm, a spike of signal corresponding to chlorophyll fluorescence was observed especially under morning solar radiation (Fig. 5A) (labelled as O2-A). However, chlorophyll signal at O2-B near 687 nm solar Fraunhofer line could hardly be detected since 687 nm coincides with the steep increase in “red edge” reflectance by leaves (Fig. 5A). After first- order differentiation of the reflectance spectra, the red edge reflectance signal no longer interferes with the reading of chlorophyll fluorescence at 687 nm (Fig. 5B) (labelled as O2-B). In this way, quantification of chlorophylls and estimation of the spread and den- sity of vegetative plant tissue can be non-invasively and even remotely monitored as plant vegetation performance mapped by remote-sensing satellites (Meroni et al., 2009; Guanter et al., 2010; Mazzoni et al., 2012). However, we have to be cautious about the handling of fluorescence data to assess the area of leaf coverage since fluorescence signals can poten- tially report the status of gross photosynthesis (with- out considering the rate of respiration) and there- fore, it may be altered over the course of the day. The fate of light energy reaching the plant leaf sur- face can be expressed as follows: J= R+T+H+F+P [1] j= J-R-T [2] where J, R, T, H, F, P, and j stand for incident light, reflection, transmittance, heat loss, fluorescence, photosynthesis, and captured light energy, respec- tively. Then, the fate of j can be traced as follows: j= H+F+P [3] P= j-H-F [4] In this study, we directly and fully monitored J (Fig. 4) (solar spectrum), R (Fig. 5A), and T (Fig. 4) (canopy spectrum), and partial F, the intensity of which is proportional to the total F (Fig. 5A, B). By definition, j can be readily estimated from recorded J, R and T. Therefore, the rate of gross photosynthesis (P) under constant or known j should be negatively proportional to the rate of heat loss (H) + fluores- cence (F). Assuming that H is constant (actual changes in local heat loss in the leaves should be determined in future experiments), changes in F indi- cate the photosynthetic status of the plants. In fact, quantification of fluorescence signal and monitoring of its temporal changes can be readily performed after normalization with green reflection (Fig. 5B, C). Taken together, the data in figure 5C suggest that L. japonicum plants are fully ready for photosynthesis only after midday. Need for the evaluation of photosynthesis We have recently proposed a series of practical equations designed to describe the collective gross photosynthetic response within the plant canopy (Okamoto et al., 2016). Using our equations, the pho- tosynthetic capacity in the plant canopy structure can be simply simulated based on minimal sampling of a single top-positioned leaf through measurement of (i) PI-curve in a horizontally placed single leaf, (ii) state of dark respiration in a single leaf, and (iii) transmittance through a single leaf. As pointed out by Monsi and Saeki (2005), T through layer of leaves can be expressed according to the definition by Beer-Lambert law as follows: T=e-ax [5] where a and x are absorption coefficient and length of the path within the leaf layer, respectively. For simplification of the model, we assume that the canopy structure consists of uniform leaves. By experimentally determining the value for T in a single leaf, we can approximate the total light used for pho- tosynthesis within the canopy structure as follows: [6] where i is the number of leaves (i=0 is initial light intensity above the leaves). Today, Michaelis- Menten-type photosynthetic equation proposed by Platt and Jasby (1976) is widely accepted by the plant research community to describe the nature of gross photosynthesis as below: [7] Recently, we proposed that photosynthetic light response curves can be generated based on a limited number of experimental data points through applica- tion of Platt-Jasby equation by determining Pmax val- ues and Kj values from least-sized experiments (Nagasawa et al., 2015). By substituting J in equation [7] with the total Hara et al. - Optical evaluation of the shading properties of Lygodium japonicum 65 light used for photosynthesis within the canopy as shown in equation [6], we can obtain the following equation: [8] where Pn stands for P in the nth leaf in the canopy. Since the collective light yield rapidly converges, k can be replaced with ∞ in a practical sense. This equation can be rewritten to modify the apparent Michaelis constant as follows: [9] By accurately determining P or total P in the canopy through a model experiment, we can more accurately estimate the local heat loss (H) on the leaf as: H= j-F-P [10] Climbing plants It is well known that climbing plants, as represent- ed by the tendril-bearing plant families, chiefly belong to higher flowering plant families such as Vitaceae, Bignoniaceae, Passifloraceae and Cucurbitaceae (Fabre, 1855; Darwin, 1875; Gerrath et al., 2008), many of which are agriculturally and eco- nomically important (Kawano et al . , 2012). Interestingly, only a few climbing species can be found among the seedless vascular plant lineages, including ferns (Darwin, 1875). Many more climbing fern species may have been lost in the course of evo- lution, since it is believed that there was a dramatic drop in the diversity and abundance of most fern species, inversely-proportional to the burst of diversi- fication in angiosperms during the Cretaceous period (Schneider et al., 2004). Timing of model experiments We planned to examine the slowing effects of L. japonicum canopy on both local heating during day- time and local cooling during nighttime; for this pur- pose, early October (2014) was chosen as the timing for model experiments. Although the attempt pre- sented here provides preliminary data in support of the thermal buffering capacity of L. japonicum canopy, further model experiments taking place under two extreme conditions, namely in mid-sum- mer and mid-winter, are required in order to fully assess the thermal buffering capacity of this species. Finally, there is great interest in assessing the quanti- tative heat balance and the radiation balance on the surface of walls or roofs based on the larger scale experiment with special reference to the thermal buffering effect of L. japonicum in all seasons in Japan. Future environmental studies Green components covering buildings and walls in urban areas are exposed not only to natural environ- mental stresses but also to artificial stressful condi- tions, chiefly exposure to polluted air containing ozone (Kadono et al., 2006; Tran et al., 2013) and related oxidants (Yukihiro et al., 2012). Most plants exposed to such oxidative stress readily develop visi- ble symptoms on the leaves reflecting the onset of programmed cell death (Kadono et al., 2010). The sensitivity and/or tolerance of L. japonicum to such stressful conditions must be studied prior to its wider application in urban greening projects. 4. Conclusions The minimal thermal analysis of the sun-shading effect of L. japonicum canopy was performed by monitoring changes in tile surface temperature. In order to optically monitor the natural shading and growth properties of a green canopy consisting of the leaves of a climbing fern, the following optical approaches have been performed for the first time: here, optical properties of L. japonicum under solar incident light, namely, the natural shading and grow- ing properties of green canopy were studied. The incident solar radiation spectrum (J), leaf transmit- tance (T) spectrum, and leaf-reflectivity spectrum (R) were measured. In the reflectivity spectrum, con- comitant chlorophyll fluorescence signal (F) was detected at 760 nm, corresponding to the O2-A Fraunhofer line. Data suggests that the daily change in photosynthetic status (P) can potentially be traced by monitoring the change in relative F in relation to the estimated heat loss (H) and measured J, R, and T. Acknowledgements This work was supported by a grant from the Regional Innovation Strategy Support Program imple- mented by Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan. Adv. Hort. Sci., 2016 30(2): 59-67 66 References ARDILA A.V.H., RESTREPO M.C.G., MONTOYA L.F.E., SEPUL- VEDA O.E.C., ACOSTA A.C.R., 2009 - Green walls: An environmental alternative for the city. - Proc. 26th Int. Conf. Passive Low Energy Architect., 6. DARWIN C., 1875 - The movements and habitats of climb- ing plants. 2nd Edition. John Murray, London. UK. French translation by R. GORDON: Les Mouvements et les habitudes des plantes glimpantes. Publisher, C. Reinwald. Paris. 1890. FABRE J.H., 1855 - De la nature des vril les des Cucurbitacée. - Bull. Soc. Bot. France, 2: 512-518. GANDY M., 2010 - The ecological facades of Patrick Blanc. - Architect. Design, 80: 28-33. GERRATH J.M., GUTHRIE T.B., ZITNAK T.A., POSLUSZNY U., 2008 - Development of the axillary bud complex in Echinocystis lobata (Cucurbitaceae): Interpreting the cucurbitaceous tendril. - Am. J. Bot., 95: 773-781. GORDON D.R., THOMAS K.P., 1997 - Strangers in paradise. Impact and management of nonindigenous species in Florida. Chapter 2. Florida’s invasion by nonindige- nous plants: History, screening, and regulation. - Island Press, Washington DC, USA, pp. 21-37. GUANTER L., ALONSO L., GÓMEZ-CHOVA L., MERONI M., PREUSKER R., FISCHER J., MORENO J., 2010 - Developments for vegetation fluorescence retrieval from spaceborne high-resolution spectrometry in the O 2 -A and O 2 -B absorption bands. - J. Geophys. Res., 115: D19303. doi:10.1029/2009JD013716. HUNTER A.M., WILLIAMS N.S.G., RAYNER J.P., AYE L., HES D., LIVESLEY S.J., 2014 - Quantifying the thermal perfor- mance of green façades: A critical review. - Ecol. Engin., 63: 102-113. KADONO T., TRAN D., ERRAKHI R., HIRAMATSU T., MEIMOUN P., BRIAND J., IWAYA-INOUE M., KAWANO T., BOUTEAU F., 2010 - Increased anion channel activity is an unavoidable event in ozone-induced programmed cell death. - PLoS ONE 5: e13373. KADONO T., YAMAGUCHI Y., FURUICHI T., HIRONO M., GARREC J.-P., KAWANO T., 2006 - Ozone-induced cell death mediated with oxidative and calcium signaling pathways in tobacco Bel-W3 and Bel-B cell suspension cultures. - Plant Signal. Behav., 1: 312-322. KAWANO T., 2015 - Pteridophyta as active components in the local ecosystems in the gardening, agricultural and horticultural sceneries in Japan. - Adv. Hort. Sci., 29: 41- 47 KAWANO T., ADACHI M., KURATA H., AZUMA R., SHIMOKAWA K., 1999 - Calcium-dependent catabolism of phaeophorbide a in tomato fruit. - J. Japan. Soc. Hort. Sci., 68: 810-816. KAWANO T., KAWANO A., KAWANO M., 2012 - Simplified exercise for mechanical repositioning of growing run- ners of forcing-cultured cucumber plants against the supporting tendril tensile strength. - Environ. Control Biol., 50: 415-423. KELLER R.C., 2013 - Place matters: Mortality, space, and urban form in the 2003 Paris heat wave disaster. - French Historical Studies, 36: 299-330. LIN C., KADONO T., SUZUKI T., YOSHIZUKA K., FURUICHI T., YOKAWA K., KAWANO T., 2006 - Mechanism for tem- perature-shift-responsive acute Ca2+ uptake in suspen- sion-cultured tobacco and rice cells . - Cryobio. Cryotechnol., 52: 83-89. MAZZONI M., MERONI M., FORTUNATO C., COLOMBO R., VERHOEF W., 2012 - Retrieval of maize canopy fluores- cence and reflectance by spectral fitting in the O 2 -A absorption band. - Remote Sens. Environ., 124: 72-82. MERONI M., ROSSINI M., GUANTER L., ALONSO L., RASCH- ER U., COLOMBO R., MORENO J., 2009 - Remote sens- ing of solar-induced chlorophyll fluorescence: Review of methods and applications. - Remote Sens. Environ., 113: 2037-2051. MONSI M., SAEKI T., 2005 - On the factor light in plant communities and its importance for matter production. - Ann. Bot., 95: 549-567. NAGASAWA K., IWASE J., COMPARINI D., KAWANO T., 2015 - Empirical and simulative evaluations of white fluorescence-type light emitting diodes as algal grow- ing light sources based on the photosynthetic oxygen evolution by Synechocystis spp. PCC6803. - Environ. Cont. Biol., 53: 169-173. OKAMOTO Y., HARAGUCHI A., SUZUKI T., KAWANO T., 2016 - New discussion on Boysen-Jensen’s photosyn- thetic response curves under plant canopy and proposal of practical equations for monitoring and management of canopy photosynthesis. - Environ. Control Biol., 4: 7- 16. OKEIL A., 2010 - A holistic approach to energy efficient building forms. - Energy Build., 42: 1437-1444. PÉREZ G., COMA J., MARTORELL I., CABEZA L.F., 2014 - Vertical greenery systems (VGS) for energy saving in buildings: a review. - Renew. Sustain. Energy Rev., 39: 139-165. PLATT T., JASBY A.D., 1976 - The relationship between pho- tosynthesis and light for natural assemblages of coastal marine phytoplankton. - J. Phycol., 12: 421-430. SAFIKHANI T., ABDULLAH A.M., OSSEN D.R., BAHARVAND M., 2014 - A review of energy characteristic of vertical greenery systems. - Renew. Sustain. Energy Rev., 40: 450-462. SCHNEIDER H., SCHUETTPELZ E., PRYER K.M., CRANFILL R., MAGALLÓN S., LUPIA R., 2004 - Ferns diversified in the shadow of angiosperms. - Nature, 428: 553-557. TACHIBANA D., NAOKI S., MAKI T., SATO Y., KIKUCHI S., IMAI K., 2011 - Important issues in green wall planning necessary to create the fine greening of urban areas. - AIJ J. Technol. Design, 17: 699-702. TAKAYAMA N., KAWAMURA K., YAMAMOTO H., NOBORI S., TOMINAGA Y., 2014 - Quantitative assessment of plant water consumption in the summer after creating a green curtain by using ivy morning glory on a south- Hara et al. - Optical evaluation of the shading properties of Lygodium japonicum 67 facing wall. - J. Agric. Meteorol., 70: 55-67. TRAN D., KADONO T., MOLAS M.L., ERRAKHI R., BRIAND J., BILIGUI B., KAWANO T., BOUTEAU F., 2013 - A role for oxalic acid generation in ozone-induced signalization in Arabidopsis cells. - Plant Cell Environ., 36: 569-578. YAMASAKI M., MIZUTANI A., OHSAWA T., 2009 - Cooling load reduction effect of green roof and green wall in the case of building with thermal thin wall. - AIJ J. Technol. Design, 15: 155-158. YUKIHIRO M., HIRAMATSU T., BOUTEAU F., KADONO T., KAWANO T., 2012 - Peroxyacetyl nitrate-induced oxida- tive and calcium signaling events leading to cell death