Actinidia Deliciosa Research Articles

Optical properties of different kiwifruit cultivars (Actinidia deliciosa and Actinidia chinensis) and their correlation with internal quality

It has been reported that fruit cultivars could be detected by using near-infrared spectroscopy. Therefore, it is doubted that the optical properties (OPs) have differences among different fruit cultivars. However, it is not clear the difference in OPs and whether there is a difference in the relationship between OPs and internal quality. To answer these questions, four kiwifruit cultivars in two species, i.e., ‘Hayward’ and ‘Xuxiang’ of Actinidia deliciosa and ‘Huayou’ and ‘Hongyang’ of Actinidia chinensis, were selected as representative samples to obtain OPs (absorption coefficient μa and reduced scattering coefficient μs') of pulp and peel in storage and 950–1650 nm using an integrating sphere system. Then the relationship between the OPs and internal quality (soluble solids content (SSC), moisture content, and firmness) and microstructure were analyzed. Moreover, the optical parameter with greater potential in classifying kiwifruit cultivars was investigated. The results showed that the changes in μa and μs' with time differed among the four cultivars. Significant differences in the values of μa and μs' were noted among the four cultivars at some given times. For a given species, the investigated two cultivars had an obvious difference in OPs. Below about 1400 nm, the pulp’s μa of ‘Hayward’, ‘Huayou’, and ‘Hongyang’ was positively correlated with SSC and negatively related to moisture content and firmness, and the correlation coefficients changed little with wavelength. However, the correlation coefficients changed greatly for ‘Xuxiang’. Kiwifruit cultivars affect OPs and their relationship with the internal quality. The modeling results of the linear discriminant analysis showed that the μa had greater potential than μs' in identifying kiwifruit cultivars. The study provides useful information for identifying fruit cultivars and internal quality by using near-infrared spectroscopy technology.

Benefits of modified atmosphere packaging in maintaining ‘Hayward’ kiwifruit quality at room temperature retail conditions

ABSTRACT Modified atmosphere packaging (MAP) is a promising approach to extend the storage life of kiwifruit (Actinidia deliciosa) and reduce food waste at retail. To investigate the effect of MAP on maintaining fruit quality during post-storage shelf life, ‘Hayward’ kiwifruit were stored in MAP or air (perforated polyethylene film) at 1°C 60%–70% RH for 35 days before being repacked in either perforated film (air), a non-perforated (MAP) retail bag or in MAP with an ethylene scrubber (ES) and stored at 20°C 67%–70% RH for 10 days (simulating retail conditions). The atmospheres created by MAP were 12%–15% O2 + 3%–4% CO2 at 1°C and 12%–16% O2 + 7%–10% CO2 at 20°C. MAP reduced kiwifruit softening during coolstorage, and this benefit was maintained during subsequent shelf life. However, MAP in simulated retail conditions benefited only weight loss and SSC. Ethylene was detected only in retail bags with rotten fruit, including one with an ES, suggesting that an ES may not be sufficient to manage ethylene in retail conditions. The application of MAP in retail as a means of reducing fruit losses at the end of the supply chain requires further research attention.

Valorization of Kiwi Peels: Fractionation, Bioactives Analyses and Hypotheses on Complete Peels Recycle.

Kiwi fruit samples (Actinidia deliciosa Planch, cv. Hayward) represent a suitable and good source for fibers obtainment as well as for polyphenolic and carotenoid extraction. With this aim, in this study they were submitted to a double phase extraction to separate insoluble fibers by an organic phase containing lipophilic substances and an hydroalcoholic phase containing polyphenols and soluble fibers. Insoluble fibers could be separated by filtration and sent to be micronized and reused. Hydroalcoholic fractions were then furtherly fractionated by solid-phase extraction. Data coming from the color CIEL*a*b* and the HPLC-DAD analyses of the extracts were compared and correlate with those coming from the SPME-GC/MS analysis of either the finely shredded peels or of the extracts. The obtained extracts were also submitted to anti-radical activity evaluation and anti-Candida activity. Results show that all of the obtained residues are value added products. Hypotheses were also made about the nature and the possible recycle of the obtained purified solid residue.

Transcriptional regulation of KCS gene by bZIP29 and MYB70 transcription factors during ABA-stimulated wound suberization of kiwifruit (Actinidia deliciosa)

BackgroundOur previous study has demonstrated that the transcription of AchnKCS involved in suberin biosynthesis was up-regulated by exogenous abscisic acid (ABA) during the wound suberization of kiwifruit, but the regulatory mechanism has not been fully elucidated.ResultsThrough subcellular localization analysis in this work, AchnbZIP29 and AchnMYB70 transcription factors were observed to be localized in the nucleus. Yeast one-hybrid and dual-luciferase assay proved the transcriptional activation of AchnMYB70 and transcriptional suppression of AchnbZIP29 on AchnKCS promoter. Furthermore, the transcription level of AchnMYB70 was enhanced by ABA during wound suberization of kiwifruit, but AchnbZIP29 transcription was reduced by ABA.ConclusionsTherefore, it was believed that ABA enhanced the transcriptional activation of AchnMYB70 on AchnKCS by increasing AchnMYB70 expression. On the contrary, ABA relieved the inhibitory effect of AchnbZIP29 on transcription of AchnKCS by inhibiting AchnbZIP29 expression. These results gave further insight into the molecular regulatory network of ABA in wound suberization of kiwifruit.

Comparative transcriptome and metabolome analysis reveal key regulatory defense networks and genes involved in enhanced salt tolerance of Actinidia (kiwifruit).

The Actinidia (kiwifruit) is an emerging fruit plant that is severely affected by salt stress in northern China. Plants have evolved several signaling network mechanisms to cope with the detrimental effects of salt stress. To date, no reported work is available on metabolic and molecular mechanisms involved in kiwifruit salt tolerance. Therefore, the present study aims to decipher intricate adaptive responses of two contrasting salt tolerance kiwifruit species Actinidia valvata [ZMH (an important genotype), hereafter referred to as R] and Actinidia deliciosa ['Hayward' (an important green-fleshed cultivar), hereafter referred to as H] under 0.4% (w/w) salt stress for time courses of 0, 12, 24, and 72hours (hereafter refered to as h) by combined transcriptome and metabolome analysis. Data revealed that kiwifruit displayed specific enrichment of differentially expressed genes (DEGs) under salt stress. Interestingly, roots of R plants showed a differential expression pattern for up-regulated genes. The KEGG pathway analysis revealed the enrichment of DEGs related to plant hormone signal transduction, glycine metabolism, serine and threonine metabolism, glutathione metabolism, and pyruvate metabolism in the roots of R under salt stress. The WGCNA resulted in the identification of five candidate genes related to glycine betaine (GB), pyruvate, total soluble sugars (TSS), and glutathione biosynthesis in kiwifruit. An integrated study of transcriptome and metabolome identified several genes encoding metabolites involved in pyruvate metabolism. Furthermore, several genes encoding transcription factors were mainly induced in R under salt stress. Functional validation results for overexpression of a candidate gene betaine aldehyde dehydrogenase (AvBADH, R_transcript_80484) from R showed significantly improved salt tolerance in Arabidopsis thaliana (hereafter referred to as At) and Actinidia chinensis ['Hongyang' (an important red-fleshed cultivar), hereafter referred to as Ac] transgenic plants than in WT plants. All in all, salt stress tolerance in kiwifruit roots is an intricate regulatory mechanism that consists of several genes encoding specific metabolites.

Patterns of genomic divergence in sympatric and allopatric speciation of three Mihoutao (Actinidia) species.

Isolation by geographic distance is involved in the formation of potential genomic islands and the divergence of genomes, which often result in speciation. The mechanisms of sympatric and allopatric speciation associated with geographic distance remain a topic of interest to evolutionary biologists. Here, we examined genomic divergence in three Actinidia species from large-scale sympatric and allopatric regions. Genome sequence data revealed that hexaploid Actinidia deliciosa originated from Actinidia chinensis and supported the speciation-with-gene-flow model in sympatric regions. The common ancestor of Actinidia setosa and A. deliciosa migrated from the mainland to the Taiwan Island ~2.91 Mya and formed A. setosa ~0.92 Mya, and the speciation of A. setosa is consistent with the divergence-after-speciation model with selective sweeps. Geographic isolation resulted in population contraction and accelerated the process of lineage sorting and speciation due to natural selection. Genomic islands contained genes associated with organ development, local adaptation, and stress resistance, indicating selective sweeps on a specific set of traits. Our results highlight the patterns of genomic divergence in sympatric and allopatric speciation, with the mediation of geographic isolation in the formation of genomic islands during Actinidia speciation.

Influence of Bee Scent and other indigenous bee attractants on bee activity and fruiting behaviour of kiwifruit (Actinidia deliciosa A. Chev.)

Kiwifruit is a dioecious plant requiring cross pollination. The nectar in kiwifruit flowers is negligible which makes it less attractive to honey bees. Hand pollination is a common practice for effective pollination but this practice is inevitable, laborious and time consuming. Spraying of bee attractants during the periods of anthesis can be helpful in increasing the bee visitation to the flowers and improve yield as well as quality of kiwifruits. Keeping in view the possible beneficial effects of bee attractants, an experiment was carried out during 2018–19 to compare the practice of hand pollination with the application of commercial bee attractant ‘Bee Scent’ (1.25%) and indigenous bee attractants like jaggery solution (10%), sugar solution (10%), honey solution (10%) and sugarcane juice (10%) for their effects on bee activity, fruit set and fruit quality of kiwifruit. The sprays of Bee Scent to the flowers resulted in significant improvement in bee visitation to the flowers, fruit set, yield, proportion of ‘A’ and ‘B’ grade fruits, fruit size & weight, number of seeds, TSS, sugars and ascorbic acid contents. Sugarcane juice was also found equally effective in improving bee activity, fruit set and fruit quality, thus shown the potential to be used as a bee attractant in commercial kiwifruit production system.

Phytochemical analysis and antioxidant defense of kiwifruit (Actinidia deliciosa) against pancreatic cancer and AAPH-induced RBCs hemolysis

Kiwifruit (Actinidia deliciosa) is a superb nutritional source of phenolic compounds that are beneficial in the prevention of different diseases. The main goal of the current study was to estimate the oxidative activity and compare the effect of the ethanol extract of this fruit's peel and flesh on pancreatic cancer against pancreatic cancer and in vitro 2, 2-azobis-2-amidinopropane dihydrochloride (AAPH) erythrocytes hemolytic oxidative damage. Firstly, HPLC was utilized to identify the phenolic compounds in each extract that showed that p-coumaric acid & ferulic acid (in the peel), syringic acid & cinnamic acid (in the flesh) were the most abundant. Concerning the anti-cancer effect, flesh extract exhibited more cytotoxic impact as detected by the reduction of PANC-1 cell line viability with IC50 of 232.89 µg/ml contrasted with the IC50 of the peel extract (556.60 µg/ml). Relative to ascorbic acid, both kiwi extracts have been considerably successful in diminishing hemolysis, thiobarbituric acid reactive substances (TBARS) and GSH levels of AAPH-induced RBCs. Interestingly, with 80 μg/ml, the ethanol peel extract returned the TBARS and GSH levels to the normal level of RBCs (0.022 and 2.86 nmole/mg hemoglobin, respectively).

Effect of ozone treatment on physicochemical parameters and ethylene biosynthesis inhibition in Guichang Kiwifruit

To determine whether ozone can regulate fruit ripening and delay fruit aging, Kiwifruit (Actinidia deliciosa 'Guichang') was fumigated with different ozone concentrations (100 μL/L, 200 μL/L, 300 μL/L) for 3 h, stored at 1 °C and 85 ± 5% RH for three months, and then matured at 20 °C and 85% RH for 12 days. Compared with controls, the optimal concentration of ozone delayed kiwifruit ripening during cold storage by delaying the respiratory burst that precedes fruit decay. Consequently, fruit firmness, nutrient content, and enzyme activity remained stable; the expression of AdACS1 and AdACO1 as well as the activity of ACC synthetase (ACS) and ACC oxidase (ACO) was downregulated, whereby ACC and MACC were accumulated. In addition, ozone-treated fruit showed significantly reduced infection with grey mold. The effect of ozone on kiwifruit at 200 μL/L was the best suited for delaying fruit senescence, maintaining high quality during storage and fruit ripening compared with other fruits. Overall, our study indicated that ozone may play a major residual role in the physiological process of fruit ripening; furthermore, ozone can affect ethylene biosynthesis and fruit changes associated with endogenous ethylene production.

Growth Inhibitory Activity of Pruning Branch Wastes from Kiwifruit Cultivation on Three Weed Species

The regular pruning in the cultivation of kiwifruits (Actinidia deliciosa (A. Chev.) C.F. Liang et A.R. Ferguson) is necessary to maintain fruit productivity and quality, and the pruning generates a significant amount of wastes. In this study, allelopathic activity of pruning branch wastes was investigated to discover beneficial applications of the wastes. An aqueous methanol extract of pruning branch wastes inhibited the growth of cress (Lepidum sativum L.), lettuce (Lactuca sativa L.) and alfalfa (Medicago sativa L.) and weed species, Lolium multiflorum Lam., Vulpia myuros (L.) C. C. Gmel., and Echinochloa crus-galli (L.) P.Beauv. Significant reductions in the growth were observed as the extract concentration was increased. The effectiveness of the extract varied by these plant species. The extract was then separated by several chromatographies with monitoring the inhibitory activity and the most active substance in the extract was isolated. The substance may work as an allelopathic agent because of its growth inhibitory activity. The present research suggests that kiwifruit pruning branches wastes may have allelopathic activity and be potentially useful for weed control in several agricultural field conditions. Further investigation is, however, necessary in the field conditions to develop the practical application of the pruning wastes.

Comparison of waterlogging tolerance between Actinidia macrosperma and Actinidia deliciosa

Comparison of waterlogging tolerance between <i>Actinidia macrosperma</i> and <i>Actinidia deliciosa</i>

Multidimensional analysis of x-ray fluorescence spectra as a possible approach for a comparative study of the elemental composition of fruit and seeds of Mangifera indica, Actinidia deliciosa, Nigella sp

Multidimensional analysis of x-ray fluorescence spectra as a possible approach for a comparative study of the elemental composition of fruit and seeds of Mangifera indica, Actinidia deliciosa, Nigella sp

One-step green synthesis of ZnFe2O4 anodes for Li-ion batteries

The Zinc Ferrite (ZnFe2O4) spinel nanoparticles have been successfully prepared by green sol–gel synthesis mode employing Actinidia deliciosa fruit extract as reducing agent. The target application of the prepared material is anode part in Li ion batteries. The prepared ZnFe2O4 nanoparticles are subjected to different analyses and the results are promising for this material to serve as anode in Li ion batteries. The structural analysis by means of X-ray diffraction technique reveals pure cubic structure of this material with a crystallite size of 28 nm. The morphological pattern recorded by means of electron microscopes reveal cube shaped grains with mixed dimensions, within 50 nm. The Raman analysis clarifies the high crystalline nature of the prepared sample with sharp peaks. Existence of carbon residues as a result of green reducing agents inside the ZnFe2O4 matrix are ensured by CC peaks in FTIR spectra. The same has been verified by means of EDX analysis as well. The electrochemical activities and electrical conductivity values of the material seems to be positive towards the anodic application of ZnFe2O4 in Li ion batteries.

The actinidia arguta ‘Hortgem Thai’ and actinidia deliciosa ‘Hayward’ kiwi fruit as a source of exogenous atioxidants

The aim of this study was to estimate the content of exogenous antioxidants in kiwi fruits available in Gdynia, Poland, and their ability to reduce free radicals. The test material consisted of mini kiwi fruit (Actinidia arguta) of the ‘Hortgem Thai’ cultivar and kiwi fruit (Actinidia deliciosa) of the ‘Hayward’ cultivar. The carotenoid pigments were determined by the Lichtenthaler method, vitamin C in accordance with PN-A-04019:1998, polyphenols by the Folin-Ciocialteu method and the ability to reduce free radicals using a synthetic DPPH radical. One-way analysis of variance was used to determine the effect of fruit species on the quality traits analysed. The significance of differences between the means was determined using Tukey’s test. Relationships were considered statistically significant at p &lt; 0.05. Correlation coefficients between the antioxidant activity of kiwi fruit and the content of exogenous antioxidants were also determined. The results showed that Actinidia arguta has significantly higher contents of exogenous antioxidants than Actinidia deliciosa. The antioxidant properties of this fruit were also found to be mainly due to its vitamin C content.

Transcriptomic Analysis of Sex-Associated DEGs in Female and Male Flowers of Kiwifruit (Actinidia deliciosa [A. Chev] C. F. Liang &amp; A. R. Ferguson)

Kiwifruit (Actinidia deliciosa [A. Chev.], C.V. Liang &amp; A. R. Ferguson, 1984) is a perennial plant, with morphologically hermaphroditic and functionally dioecious flowers. Fruits of this species are berries of great commercial and nutritional importance. Nevertheless, few studies have analyzed the molecular mechanisms involved in sexual differentiation in this species. To determine these mechanisms, we performed RNA-seq in floral tissue at stage 60 on the BBCH scale in cultivar ‘Hayward’ (H, female) and a seedling from ‘Green Light’ × ‘Tomuri’ (G × T, male). From these analyses, we obtained expression profiles of 24,888 (H) and 27,027 (G × T) genes, of which 6413 showed differential transcript abundance. Genetic ontology (GO) and KEGG analysis revealed activation of pathways associated with the translation of hormonal signals, plant-pathogen interaction, metabolism of hormones, sugars, and nucleotides. The analysis of the protein-protein interaction network showed that the genes ERL1, AG, AGL8, LFY, WUS, AP2, WRKY, and CO, are crucial elements in the regulation of the hormonal response for the formation and development of anatomical reproductive structures and gametophytes. On the other hand, genes encoding four Putative S-adenosyl-L-methionine-dependent methyltransferases (Achn201401, Achn281971, Achn047771 and Achn231981) were identified, which were up-regulated mainly in the male flowers. Moreover, the expression profiles of 15 selected genes through RT-qPCR were consistent with the results of RNA-seq. Finally, this work provides gene expression-based interactions between transcription factors and effector genes from hormonal signaling pathways, development of floral organs, biological and metabolic processes or even epigenetic mechanisms which could be involved in the kiwi sex-determination. Thus, in order to decode the nature of these interactions, it could be helpful to propose new models of flower development and sex determination in the Actinidia genus.

First Report of Crown Gall of Kiwifruit (Actinidia deliciosa) Caused by Agrobacterium fabacearum in China and the Establishment of Loop-Mediated Isothermal Amplification Technique.

Kiwifruit is moderately sweet and sour and quite popular among consumers; it has been widely planted in some areas of the world. In 2019, the crown gall disease of kiwifruit was discovered in the main kiwifruit-producing area of Guizhou Province, China. This disease can weaken and eventually cause the death of the tree. The phylogeny, morphological and biological characteristics of the bacteria were described, and were related to diseases. The pathogenicity of this species follows the Koch hypothesis, confirming that A. fabacearum is the pathogen of crown gall disease of kiwifruit in China. In this study, Loop-mediated isothermal amplification (LAMP) analysis for genome-specific gene sequences was developed for the specific detection of A. fabacearum. The detection limit of the LAMP method is 5 × 10−7 ng/μL, which has high sensitivity. At the same time, the amplified product is stained with SYBR Green I after the reaction is completed, so that the amplification can be detected with the naked eye. LAMP analysis detected the presence of A. fabacearum in the roots and soil samples of the infected kiwifruit plant. The proposed LAMP detection technology in this study offers the advantages of ease of operation, visibility of results, rapidity, accuracy and high sensitivity, making it suitable for the early diagnosis of crown gall disease of kiwifruit.

Establishment of Tissue Culture System of Actinidia deliciosa Cultivar “Guichang”

In order to breed virus-free plantlets of the kiwifruit cultivar “Guichang,” which belongs to Actinidia deliciosa, in this study, stem segments with buds were used as explants, the establishment of a tissue culture rapid propagation system was carried out, and then the virus status of tissue culture plantlets was detected via the real-time reverse transcription-polymerase chain reaction (RT-qPCR) method. The tissue culture rapid propagation system proved that the contamination and browning rates could be controlled below 20% and the survival rate could be exceeded by 70% when the single bud stem segment of “Guichang” kiwifruit was sterilized with 70% alcohol for 30–60 s and 15% NaClO for 15 min, respectively. Meanwhile, we screened the hormone concentration to get better results, and the appropriate medium for adventitious bud induction was MS + 6-BA (1.0 mg/L) + IBA (0.2 mg/L); for proliferation, it was MS + 6-BA (1.0 mg/L) + IBA (0.1 mg/L); and for rooting, it was 1/2 MS + IBA (0.3 mg/L), and the efficiency of induction, proliferation, and rooting could reach 74.07%, 79.63%, and 85.18%, respectively. In addition, the RT-qPCR results demonstrated that the infection rate of 9 viruses: apple stem grooving virus (ASGV), cucumber mosaic virus (CMV), Actinidia virus X (AVX), cucumber necrosis virus (CNV), ribgrass mosaic virus (RMV), citrus leaf blotch virus (CLBV), Actinidia virus B (AcVB), Pelargonium zonate spot virus (PZSV), and cherry leaf roll virus (CLRV) in the “Guichang” kiwifruit tissue culture plantlets was 0. This study could lay a foundation for the production of “Guichang” kiwifruit tissue culture seedlings, and the medium formula provided in this study was useful for the industrial rapid propagation of “Guichang” plantlets.

Kiwifruit (Actinidia deliciosa) propagation: Influence of stock plant sexuality on root development

Kiwifruit (Actinidia deliciosa) propagation: Influence of stock plant sexuality on root development

Undifferentiated In Vitro Cultured Actinidia deliciosa as Cell Factory for the Production of Quercetin Glycosides.

Land plants produce a vast arsenal of specialized metabolites and many of them display interesting bioactivities in humans. Recently, flavonol quercetin gained great attention in the light of the COVID-19 pandemic because, in addition to the anti-inflammatory, antiviral and anti-cancer activity already described, it emerged as possible inhibitor of 3CLpro, the major protease of SARS-CoV-2 virus. Plant cell and tissue culture (PCTC) is an attractive platform for the biotechnological production of plant metabolites. This technology allows a large amount of water and agricultural land to be saved and, being free of contaminants in the process, it is suitable for scaling up the production in bioreactors. In a project aimed to generate and screen in vitro plant cells for the production of valuable specialized metabolites for commercial production, we generated various cell lines from Actinidia deliciosa (kiwi fruit tree) and Actinidia chinensis (gold kiwi fruit tree), that were able to produce relevant amounts of quercetin derivatives, mainly quercetin glycosides. Three cell lines from A. deliciosa were characterized by targeted and untargeted metabolomics. In standard growing conditions, they produce and accumulate up to 13.26 mg/100 g fresh weight (419.76 mg/100 g dry weight) of quercetin derivatives. To address future industrial applications, these cell lines should be entered into an acceleration program to further increase the amount of these metabolites by optimizing the culture conditions and elicitation.

Tunable fluorescent carbon dots from biowaste as fluorescence ink and imaging human normal and cancer cells

Growing global biowaste and its environmental issues challenge the need for converting biowastes into a beneficial product. Among the biowaste, here kiwi fruit (Actinidia Deliciosa) peels are considered for the preparation of carbon dots (CDs). Using a green one-pot hydrothermal-carbonization method, kiwi fruit peels were effectively converted into valuable kiwi fruit peel carbon dots (KFP-CDs). The morphology, physio-chemical and optical properties of as-synthesized KFP-CDs were analyzed using various analytical techniques such as X-ray powder diffraction, Raman spectroscopy, attenuated total reflection-Fourier transform infrared spectroscopy, field emission scanning electron microscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, Ultraviolet–visible, and fluorescence spectroscopy. The KFP-CDs revealed a homogeneous spherical shape, monodispersed with an average size of 5 nm. The characterization confirms that KFP-CDs have functional groups such as –CN, –COOH, and –OH which are responsible for the easy dispersion of KFP-CDs in aqueous media. Without any preprocessing, KFP-CDs exhibit strong fluorescence upon exposure to UV light. Further, KFP-CDs displayed excitation-dependent fluorescence emission with a good quantum yield of about 18%. Thus by considering the excellent properties of KFP-CDs, KFP-CDs were used as fluorescent ink for drawing and writing without any capping/passivation agent. The pictures and words were instantaneously viewed when exposed to UV light. In addition, KFP-CDs tested for cell imaging in four human cell lines (normal and cancer cells) bestowed excellent biocompatibility and low cytotoxicity, which is important for the safe and long-term development of cellular imaging. The findings imply that KFP-CDs can be utilized as a cell labeling agent for mesenchymal stem cells, breast cancer, and thyroid cancer cells in vitro imaging. Thus, these observations revealed that investigating sustainable resource-based CDs can open up new avenues for tackling environmental issues.