Foliar Raffinose and Sucrose in Four Conifer Species: Relationship to Seasonal Temperature
| Autor: | D.M. Pharr, L.E. Hinesley, S.R. Funderburk, L.K. Snelling |
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| Rok vydání: | 1992 |
| Předmět: | |
| Zdroj: | Journal of the American Society for Horticultural Science. 117:852-855 |
| ISSN: | 2327-9788 0003-1062 |
| DOI: | 10.21273/jashs.117.5.852 |
| Popis: | Foliar raffinose and sucrose concentrations in eastern white pine (Pinus strobus L.), eastern redcedar (Juniperus virginiana L.), Leyland cypress (xCupressocyparis leylandii Dallim.), and Virginia pine (Pinus virginiana L.) were measured monthly over 2 years. During cold weather, foliage of white pine and redcedar contained higher concentrations of raffinose and sucrose than did Leyland cypress and Virginia pine. Rafflnose concentrations were highest during winter and were best correlated with the frequency of occurrence of daily minima ≤ 1.7C during the 30 days before sampling. Sucrose concentrations, which also reached maximum levels during the winter, were best correlated with the frequency of occurrence of daily minima ≤ 7.2C in the prior 30 days. Sucrose concentrations were relatively high during fall and spring. Raffinose and sucrose concentrations increased in response to recurring low temperature, with correlations highest for raffinose. In the fall and winter, foliar raffinose concentration increases in conifers (Little, 1970; Parker, 1959). Raffinose accumulates in Fraser fir (Abies fraseri (Pursh) Poir.) in response to low temperature and short days (Mitcham-Butler et al., 1986). This response is not confined to higher plants. A brief cold treatment (4C) of algae (Chlorella vulgaris Beyerinck) induces an accu- mulation of raffinose, and concentrations decrease when the algae are transferred to warmer temperatures (Salerno and Pon- tis, 1989). In general, high foliar raffinose concentrations are associated with greater cold hardiness (Kandler and Hopf, 1980; Parker, 1959). Fraser fir Christmas trees that are harvested after experiencing low temperatures have higher foliar raffinose concentration and exhibit better postharvest needle retention than trees precondi- tioned with higher temperatures (Mitcham-Butler et al., 1986). Although raffinose increases in the foliage of several conifers during the winter and might be involved in cold hardiness, there are no studies that compare seasonal sugar levels of different conifer species growing in the same environment. Thus, com- parisons among species from available data are difficult. Our research had two objectives: 1) determine seasonal raffinose and sucrose concentrations in the foliage of four conifer species that differ in hardiness and are important to the Christmas tree in- dustry and 2) determine if foliar raffinose and sucrose concen- trations are correlated with the occurrence of different baseline (daily minimum) temperatures during the week or month pre- ceding sampling. |
| Databáze: | OpenAIRE |
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