Funding for this column is provided by the ASCFG Research Committee.

Starch and Sugar Accumulation and its Relationship
to Plant Growth in Peony

Peony lactiflora can be found in many regions with long, cold winters and short growing seasons.  Winter deciduous, the peony survives through the winter as a dormant root mass accumulating hours of winter chill before breaking bud in spring. The rapid growth flush in spring must be fed by carbon reserves stored in the roots until the shoots and leaves develop and begin contributing, via photosynthesis, to the available carbon pool. Researchers in New Zealand worked to identify and quantify the non-structural carbohydrates through the stages of peony plant growth and development in an effort to determine how limitations in the carbon supply affect flower production and postharvest performance.
Samples were collected from mature plants of Paeonia lactiflora Pall. ‘Sarah Bernhardt’, for sugar and starch analyses. Shoot samples were collected weekly from emergence until flower harvest. Root samples were collected weekly from the beginning of the growing season until flower senescence. Additional root samples were collected monthly from flower senescence until the following spring. Samples were collected from tagged flowering shoots (at harvest stage) daily until all flower petals had abscised.
Shoots reached their full height of 93 cm (36.6 in) only 40 days after shoot emergence. Sugars detected in the developing shoots (stems, leaves and buds/flowers) were fructose, glucose, sucrose and myo-inositol, with fructose being present in the highest concentration and myo-inositol present in the lowest concentration. Starch was detected only in the developing buds, not in the leaf or stem samples.
Flowers took several days to open fully, though the researchers recognized that ‘Sarah Bernhardt’, a double, opens slower than single flower types. Within eight days of tagging the flowering shoots all the flowers had opened, and by day 9, some petal drop was observed. Eighteen days after tagging, most of the flowers had dropped all their petals.
In the roots, the combined concentration of sugars and starches were found to be lowest during the spring when growth was at its maximum, increasing then to its peak in midsummer. However, the sugar sucrose was at peak concentration in winter, when the plants were dormant. This sucrose accumulation has been associated with hardiness, or building up a tolerance to cold temperatures. Additionally, this freely available sucrose allows the plant to respond immediately to the warmer temperatures in spring since the carbohydrate reserves are able to be quickly metabolized or mobilized. This may be particularly important to sustain the life cycle in areas with a short growing season.
In their conclusion, they found that the roots became a strong sink while the shoots remained a strong sink suggesting the peony leaves quickly became net exporters of carbon. While this gives peonies a genetic advantage (in the event that their canopy was lost by a late spring frost, for example, the stored reserves would allow for survival until the following spring), it makes cultural manipulation for increased shoot production a challenge. Further research will explore shoot-thinning and an effort to alter carbon partitioning to promote increased peony production.

Walton, E.F., G.F. McLaren and H.L. Boldingh. 2007. Seasonal patterns of starch and sugar accumulation in herbaceous peony (Paeonia lactifora Pall.). Journal of Horticultural Science & Biotechnology. 82(3), pp.365-370.

Target Marketing Floral Purchases

Research conducted at Da-Yeh University in Taiwan closely examined the prepurchase process of flower buyers to determine if there was a difference between shoppers buying flowers for gift giving or shoppers buying flowers for personal use.
Consumers filled out a questionnaire to evaluate 1.) the information sources used in the flower purchase decision, 2.) the criteria used to explore floral alternatives, and 3.) the choice of retail channel and more specifically the store choice.
Nearly 500 floral shoppers participated in the study. Females accounted for 57.7% of the participants, while males made up 42.3%. Nearly 60% of the shoppers were 18-30 years old, 25.6% were 31-40 years old. The percentage continued to decline with each increasing age bracket. A total of 85% of the floral shoppers surveyed were pursuing or had attained an undergraduate or graduate degree. Of the occupational categories listed, “students” represented the largest survey group at 27.8%, followed by professionals (22.2%) and service and sales (14.4%). Gift giving was the intention of 205 survey participants, while 287 indicated they were self users of their floral purchases.
As for the prepurchase “process,” self users were most likely to window shop or use newspapers/magazines as information sources when making a flower purchase decision, while gift users were more likely to use personal preference and word of mouth as a decision-making factor. In considering floral alternatives, self users focused on longevity of the product, price and product quality. Symbolic meaning and situational value were the primary criteria considered by gift users. Not to imply longevity, price and quality are not important to gift buyers; they simply do not reflect the need of the gift giver to convey a certain intention or emotion related to the actual gift.
In choosing a floral market/store, the self users were found to use a traditional flower market with a known reputation, whereas the availability of home delivery service was the main criterion considered by gift users.
The study goes on to suggest that by recognizing that these two market segments have distinctly different prepurchase processes, marketing strategies should reflect these two audiences. For instance, if self users are the target market, window dressing and store displays should be given special attention. Also, by creating a favorable purchase experience, you can generate word of mouth buzz. Retailers should focus on emphasizing value, longevity and quality to self users, while calling attention to symbolic meaning of certain flowers to assist the gift user in a purchasing decision. Marketers who build a quality-based reputation and address added value of store services, such as delivery, will be reaching out to self users and gift users accordingly.
Future studies may look into postpurchase behaviors of consumers and how to develop consumer loyalty to products and brands in the floral market.

Huang, L. 2007. Behavioral Differences in Prepurchase Processes between Purchasers of Flowers for Self Use and for Gift Use. HortTechnology. 17(2), pp. 183-190.

Transgenic Potential for Fragrant Lisianthus

Flower scent is determined by a complex mixture of volatile molecules emitted by floral organs. Lisianthus (Eustoma grandiflorum) is naturally scentless, but has been selected as a target plant for transgenic manipulation of a metabolic pathway that may ultimately induce fragrance. Genetic research on lisianthus has already produced a glowing flower by expression of a green fluorescent protein in transgenic plants. In this study, conducted at Ben-Gurion University of the Negev in Israel, scientists attempted to induce fragrance by over-expressing the BEAT (benzyl alcohol acetyltransferase) gene from Clarkia breweri using transgenic methods. Benzyl acetate is a major compound of the volatile composition of C. breweri, gardenia and jasmine.
The transgenic lisianthus plants displayed a similar phenotype to the control plants, meaning that they looked the same. However, no change in flower fragrance was detected, presumably because no benzyl acetate was produced. Lack of fragrance may be attributed to insufficient BEAT substrate for production of benzyl acetate. Using alternative alcoholic substrates may be more efficient.
While this study did not produce the desired fragrant result, the researchers believe it does suggest that fragrances can be induced by genetic engineering, using different substrates.

Aranovich, D., E. Lewinsohn and M. Zaccai. 2007. Postharvest enhancement of aroma in transgenic lisianthus (Eustoma grandiflorum) using the Clarkia breweri benzyl alcohol actyltransferase (BEAT) gene. Postharvest Biology and Technology. 43, pp. 255-260.

Megan Bame

Megan Bame is a freelance writer in Salisbury, North Carolina. Contact her at [email protected]