maturity and emit its floral scape; this occurs when the plant is 8 to 10 years old. To reduce time to harvest, one alternative is to determine the content of fructans in young plants under different culture management techniques, partially simulating
Lucia Armin Langlé-Argüello, Gabino Alberto Martínez-Gutiérrez, Patricia Araceli Santiago-García, Cirenio Escamirosa-Tinoco, Isidro Morales, and José Raymundo Enríquez-del-Valle
Susan E. Trusty, William B. Miller, and Dale Smith
In order to more fully understand flower growth and development, we are interested in carbohydrate partitioning and metabolism in floricultural crops. In recent work with Chrysanthemum, we noted the occurrence of several early-eluting carbohydrate peaks (as detected by HPLC with a resin-based column in the calcium form). These peaks were present in flowers and stems, and in lesser amounts in leaves. Acid hydrolysis of the unknowns liberated large amounts of fructose and much smaller amounts of glucose, indicating that these peaks are fructans, or medium chain-length fructose polymers. Fructans represented 10% and 25% of the carbohydrate in a 12:5:3 methanol: chloroform: water extract of leaves and stems, respectively. Flower petals were extracted with 95%. ethanol, then with water. Fructans accounted for more than 40'% of the water soluble carbohydrate in flower bud tissue. It is likely that fructans serve as a major reserve carbohydrate in Chrysanthemum. Additional studies are underway to better characterize flower petal fructans, and to understand their role in flower development.
Jaejoon Kim and David J. Wolyn
breeding program. Compounds with cryoprotective properties such as proline, glucose, sucrose, and fructans may contribute to freezing tolerance of the overwintering asparagus crown. Proline is known to stabilize protein synthesis, increase water
Susan E. Trusty and William B. Miller
Postproduction changes in carbohydrate types and quantities in the leaves, stems, and inflorescences of pot chyrsanthemums [Dendranthema × gramfiflorum (Ramat.) Kitamura `Favor'] placed in interior conditions were investigated. Fructans, sucrose, glucose, and fructose were present in all plant parts. In inflorescences and leaves, an additional unidentified substance was present. All plant parts decreased in dry weight during the postproduction evaluation. This decrease was accompanied by overall reductions in total soluble carbohydrates (TSC) and starch. The appearance of leaves and stems was acceptable throughout the experiment. Leaves lost significant amounts of TSC during the first 4 days postproduction (DPP), due primarily to a 76% decrease in sucrose concentration. After 4 DPP, leaf and stem TSC remained relatively unchanged. In inflorescences, petal expansion continued through 12 DPP. Visible signs of senescence, including loss of turgor, color changes, and inrolling of petal edges were observed at 20 DPP, and by 28 DPP, the plants were determined unacceptable for consumer use. Inflorescences increased in fresh weight, but not dry weight, during petal expansion, then each decreased. Inflorescence TSC fell from 146 mg.g-1 dry weight at O DPP to 11 mg.g-1 at 28 DPP. Reducing sugars accounted for 84% of the inflorescence TSC at 4 DPP, dropping to 48% at 28 DPP. Fructan concentration decreased through 16 DPP and then remained unchanged, while starch levels rose from 25 to 34 mg·g -1 dry weight through 12 DPP, then decreased. Fractans decreased in polymerization during petal expansion. This result suggests an alternate use of fructans and starch as pools of available reserve carbohydrate during petal expansion in chrysanthemum.
Kelly J. Prevete, R. Thomas Fernandez, and William B. Miller
Boltonia asteroides L. `Snowbank' (Snowbank boltonia), Eupatorium rugosum L. (eastern white snakeroot), and Rudbeckia triloba L. (three-lobed coneflower) were subjected to drought for 2, 4, and 6 days during the fall and spring. Leaf gas exchange, leaf water potential, growth, and carbohydrate partitioning were measured during drought and throughout the following growing season. Leaf gas exchange of B. asteroides was not affected by drought treatment in the fall, not until day 6 of spring drought, and there were no long-term effects on growth. Transpiration and stomatal conductance of R. triloba decreased when substrate moisture decreased to 21% after drought treatment during both seasons. Assimilation of drought-treated R. triloba decreased when substrate moisture content decreased to 12% during spring but was not affected by drought in the fall. There was a decrease in the root-to-shoot ratio of R. triloba that had been treated for 4 days, which was attributed to an increase in the shoot dry weight (DW) of treated plants. Reductions in spring growth of E. rugosum were observed only after fall drought of 6 days, and there were no differences in final DWs of plants subjected to any of the drought durations. Spring drought had no effect on growth index or DW of any of the perennials. Boltonia asteroides and R. triloba had increases in low-molecular-weight sugars on day 4 of drought, but E. rugosum did not have an increase in sugars of low molecular weight until day 6 of drought. Differences in drought response of B. asteroides, E. rugosum, and R. triloba were attributed to differences in water use rates.
Steven Raines, Cynthia Henson, and Michael J. Havey
constitute ≈80% of the DW of onion ( Darbyshire and Henry, 1978 , 1979 , 1981 ; Shiomi, 1989 ) and consist mainly of glucose, fructose, sucrose, and fructan polymers ( Darbyshire and Henry, 1978 ; Shiomi, 1989 ). These fructans are an important dietary
Carmen Feller and Matthias Fink
determined by the difference of fructose before and after hydrolyzation of saccharose; 3) fructans were hydrolyzed with fructanase, then glucose and fructose were determined enzymatically using a test kit of Roche Diagnostics; and 4) fructan content was
Mark J. Howieson and Nick Edward Christians
raw materials to redevelop leaf and shoot tissue ( Davidson and Mithorpe, 1966 ; Donaghy and Fulkerson, 1998 ; Morvan-Betrand et al., 1999 ). The primary reserve carbohydrate of creeping bentgrass ( Agrostis stolonifera L.) is fructan. Fructan is
Zhimin Yang, Lixin Xu, Jingjin Yu, Michelle DaCosta, and Bingru Huang
processes, including photosynthesis, respiration, and carbohydrate accumulation ( Fry and Huang, 2004 ; Nilsen and Orcutt, 1996 ). Carbohydrates in different forms are known to serve in diverse functions. For example, starch and fructan are major sources of
Yiwei Jiang, Eric Watkins, Shuwei Liu, Xiaoqing Yu, and Na Luo
-epoxycarotenoid dioxygenase ( NCED ), aldehyde oxidase 3 ( AAO3 ), Δ 1 -pyrroline-5-carboxylate synthetase ( P5CS ), Δ 1 -pyrroline-5-carboxylate reductase ( P5CR ), fructan:fructan 1-fructosyltransferase ( 1-FFT ), sucrose synthase ( SUSY ), aquaporin ( PIP1