Seasonal pattern of cold tolerance and proteins were studied in the leaves of sibling deciduous and evergreen peach (Prunus persica). In contrast to deciduous peach that undergoes endodormancy in fall, evergreen peach does not (leaves are retained and shoot tips elongate under favorable conditions) (Arora et al., Plant Physiol. 99:1562-1568). Cold tolerance (LT50) was assessed using electrolyte leakage method. Proteins were separated by SDS-PAGE. Electroblots were probed with anti-dehydrin (Dr. T. Close) and anti-19 kD, peach bark storage protein (BSP) antibodies. LT50 of leaves successively increased from about -7C (18 Aug.) to -15C and -11.5C (23 Oct.) in deciduous and evergreen genotypes, respectively. The most apparent change in the protein profiles was the accumulation of a 60-kD protein during cold acclimation in the leaves of deciduous trees; however, it did not change significantly in evergreen peach. Immunoblots indicate that 60-kD protein is a dehydrin protein. PAGE and immunoblots indicated that 19-kD BSP disappeared progressively during summer through fall in the leaves of deciduous peach, but accumulated to large amounts in bark tissues. Similar inverse relationship for its accumulation in leaf vs. bark tissue was not evident in evergreen peach. Results indicate that BSP expression may be regulated by altered source/sink relationship.
Rajeev Arora, Michael Wisniewski, and Lisa J. Rowland
Rajeev Arora, Michael Wisniewski, and Lisa J. Rowland
Seasonal changes in cold tolerance and proteins were studied in the leaves of sibling deciduous and evergreen peach [Prunus persica (L.) Batsch]. Freezing tolerance [defined as the subzero temperature at which 50% injury occurred (LT50)] was assessed using electrolyte leakage. Proteins were separated by sodium dodecyl sulfate polyacrylamide-gel electrophoresis. Electroblots were probed with anti-dehydrin and anti-19-kD peach bark storage protein (BSP) antibodies. Leaf LT50 decreased successively from -5.8 °C on 18 Aug. to -10.3 °C in the evergreen genotype and from -7.0 °C to -15.0 °C in the deciduous genotype by 14 Oct. Protein profiles and immunoblots indicated the accumulation of a 60- and 30-kD protein during cold acclimation in the leaves of deciduous trees; however, levels of these proteins did not change significantly in the evergreen trees. Immunoblots indicate that the 60-kD protein is a dehydrin-like protein. Gel-electrophoresis and immunoblots also indicated that the 19-kD BSP progressively disappeared from summer through fall in leaves of deciduous peach but accumulated to a high level in bark tissues. A similar inverse relationship was not evident in evergreen peach.
Rajeev Arora, Michael Wisniewski, and Ralph Scorza
Deciduous fruit trees undergo endo-dormancy during fall at which time they also attain maximum cold hardiness (CH). Because these two processes occur simultaneously it is difficult to study them independently. We have been able to overcome this limitation with the use of genetically related (sibling) deciduous and evergreen peach trees. Using this system we conducted a time course study to characterize the seasonal fluctuations in CH and proteins in bark and xylem tissues. Cold hardiness (LT50) was assessed using electrolyte leakage method. Polypeptides were separated using SDS-PAGE. The data indicated that 1) CH of bark increased from -5°C (in August) to -49°C (in January) and from -3°C to -22°C for deciduous and evergreen trees, respectively. In January, under favorable conditions, evergreen trees were actively growing. 2) CH of xylem successively increased from -11°C to -36°C in deciduous trees and from -7°C to -16°C (in November) in evergreen trees and then plateaued. 3) LT50 of xylem in both genotypes closely approximated the mid-point of low temperature exotherms determined by differential thermal analysis. 4) As CH increased several qualitative and quantitative differences in polypeptides were noted between two genotypes. These changes during cold acclimation will be compared with those during de-acclimation.
J. Rodriguez-A., W.B. Sherman, R. Scorza, M. Wisniewski, and W.R. Okie
The evergreen (EVG) peach, first described in Mexico, was used as a parent with deciduous (DE) peaches to develop F1 and F2 hybrid populations in Mexico, Florida, Georgia, and West Virginia. F1 trees were DE and F2 plants segregated 3 DE: 1 EVG. In West Virginia, the most temperate location, the heterozygous class could be distinguished in the first few years of growth by late leaf abscission in the fall. Segregation ratios suggest that the EVG trait is controlled by a single gene, evg, the EVG state being homozygous recessive. Evergreen trees were characterized by insensitivity of shoot tips to daylength and failure of terminal growth to cease growth until killed by low temperature. Lateral buds of EVG trees went dormant in the fall. Deep supercooling occurred in both EVG and DE trees, but it appeared later in EVG trees, was of shorter duration, and occurred to a lesser extent. Evergreen germplasm may be useful in developing peach cultivars for frost-free subtropic and tropical areas. It also presents a useful system for studying dormancy and cold hardiness.
Thomas W. Zimmerman and Ralph Scorza
Rajeev Arora and Michael Wisniewski
The seasonal pattern of dehydrin accumulation was characterized during cold acclimation and deacclimation in the xylem tissues of genetically related (sibling) deciduous and evergreen peach (Prunus persica L.). Immunological studies indicate that a 60-kD polypeptide in peach xylem tissues is a dehydrin protein. Comparison of its accumulation pattern with seasonal fluctuations in cold hardiness indicate that dehydrin accumulated to high levels during the peak of cold acclimation. However, its accumulation was only weakly associated with cold hardiness during early stages of cold acclimation and during deacclimation. Our results indicate that factors related to supercooling rather than dehydrin accumulation may be primarily responsible for determining levels of cold hardiness during transition periods.
Youn Young Hur, Su Jin Kim, Jeong Ho Roh, Kyo Sun Park, Hae Keun Yun, Jong Chul Nam, Sung Min Jung, Sang Uk Koh, Dong Jun Im, Dong Hoon Lee, Seo June Park, and Kyong Ho Chung
-mail: email@example.com ). Literature Cited Arora, R. Winsniewski, M.E. Scorza, R. 1992 Cold acclimation in genetically related (sibling) deciduous and evergreen peach [ Prunus persica (L.) Batsch]. 1. Seasonal changes in cold hardiness and polypeptides of
Wei Hao, Rajeev Arora, Anand K. Yadav, and Nirmal Joshee
? Physiol. Plant. 101 8 16 Arora, R. Wisniewski, M.E. 1994 Cold acclimation in genetically related (sibling) deciduous and evergreen peach ( Prunus persica [L.] Batsch) II. A 60-kilodalton bark protein in cold
Danqing Li, Jiao Zhang, Jiaping Zhang, Kang Li, and Yiping Xia
., 1985 )] and ‘Evergreen’ peach [ Prunus persica ( Rodriguez-A et al., 1994 )], whereas inherited in a dominant manner in daylilies ( Dow, 2012 ; Stout, 1940 ). Thus, crosses of evergreen iris type with different wild-type deciduous ones are needed to
Hisayo Yamane, Yukinobu Kashiwa, Tomomi Ooka, Ryutaro Tao, and Keizo Yonemori
(sibling) deciduous and evergreen peach [ Prunus persica (L.) Batch] I. Seasonal changes in cold hardiness and polypeptides of bark and xylem tissues Plant Physiol. 99 1562 1568 Artlip, T.S. Callahan, A.M. Bassett, C