This report demonstrates the presence of S-ribonucleases (S-RNases), which are associated with gametophytic self-incompatibility (SI) in Prunus L., in styles of self-incompatible and self-compatible (SC) selections of tetraploid sour cherry (Prunus cerasus L.). Based on self-pollen tube growth in the styles of 13 sour cherry selections, seven selections were SC, while six selections were SI. In the SI selections, the swelling of pollen tube tips, which is typical of SI pollen tube growth in gametophytic SI, was observed. Stylar extracts of these selections were evaluated by two-dimensional polyacrylamide gel electrophoresis. Glycoproteins which had molecular weights and isoelectric points similar to those of S-RNases in other Prunus sp. were detected in all selections tested. These proteins had immunological characteristics and N-terminal amino acid sequences consistent with the S-RNases in other Prunus sp. Two cDNAs encoding glycoproteins from `Erdi Botermo' were cloned. One of them had the same nucleotide sequence as that of S4-RNase of sweet cherry (Prunus avium L.), while the amino acid sequence from the other cDNA encoded a novel S-RNase (named Sa-RNase in this study). This novel RNase contained two active sites of T2/S type RNases and five regions conserved among other Prunus S-RNases. Genomic DNA blot analysis using cDNAs encoding S-RNases of sweet cherry as probes indicated that three or four S-RNase alleles are present in the genome of each selection regardless of SI. All of the selections tested seemed to have at least one S-allele that is also found in sweet cherry. Genetic control of SI/SC in tetraploid sour cherry is discussed based on the results obtained from restriction fragment length polymorphism analysis.
Hisayo Yamane, Ryutaro Tao, Akira Sugiura, Nathanael R. Hauck and Amy F. Iezzoni
Simona Proietti, Stefano Moscatello, Fiorella Villani, Federica Mecucci, Robert P. Walker, Franco Famiani and Alberto Battistelli
, Ukraine, the United States, and Iran. There are three main cultivars of sour cherry, also known as tart cherry ( Prunus cerasus L.): caproniana or amarella cherry, with light-colored flesh; marasca, with soft red flesh and a slightly tart flavor; and
Desmond R. Layne and J.A. Flore
The source-sink ratio of l-year-old, potted `Montmorency' sour cherry (Prunus cerasus) trees was manipulated by partial defoliation (D) or continuous lighting (CL) to investigate the phenomenon of end-product inhibition of photosynthesis. Within 24 hours of D, net CO2 assimilation rate (A) of the most recently expanded source leaves of D plants was significantly higher than nondefoliated (control) plants throughout the diurnal photoperiod. Between 2 and 7 days after D, A was 30% to 50% higher and stomatal conductance rate (g,) was 50% to 100% higher than in controls. Estimated carboxylation efficiency(k) and ribulose-1,5-bisphosphate (RuBP) regeneration rate increased significantly within 2 days and remained consistently higher for up to 9 days after D. Leaf starch concentration and dark respiration rate decreased but sorbitol and sucrose concentration increased after D. The diurnal decline in A in the afternoon after D may have been due to feedback inhibition from accumulation of soluble carbohydrates (sucrose and sorbitol) in the cytosol. This diurnal decline indicated that trees were sink limited. By 9 days after D, photochemical efficiency was significantly higher than in control plants. In the long term, leaf senescence was delayed as indicated by higher A and gs in combination with higher chlorophyll content up to 32 days after D. CL resulted in a significant reduction of A, gs, k, variable chlorophyll fluorescence (Fv), photochemical efficiency, and estimated RuBP regeneration rate of the most recently expanded source leaves within 1 day. During the exposure to CL, A was reduced 2- to 3-fold and k was reduced up to 4-fold. The normal linear relationship between A and gs was uncoupled under CL indicating that A was not primarily limited by gs and since internal CO2 concentration was not significantly affected, the physical limitation to A imposed by the stomata was negligible. The decrease in Fv and photochemical efficiency indicated that leaves were photoinhibited within 1 day. The decrease in instantaneous chlorophyll fluorescence after at least 1 day of CL indicated that there was a reversible regulatory mechanism whereby the damage to photosystem II reaction centers was repaired. Leaf chlorophyll content was not altered by 1,2, or 3 days of exposure to CL, indicating that photooxidation of chlorophytl did not occur. The time to full photosynthetic recovery from CL increased as the duration of exposure increased. CL plants that were photoinhibited accumulated significant starch in the chloroplast in a companion study (Layne and Flore, 1993) and it is possible that an orthophosphate limitation in the chloroplast stroma was occurring. D plants that were continuously illuminated were not photosynthetically inhibited. After 7 days of CL, plants that were then partially defoliated yet remained in CL photosynthetically recovered within 5 days to pre-CL values. Under the conditions of this investigation, end-product inhibition of A occurred in young, potted sour cherry trees but the mechanism of action in D plants was different than in CL plants.
Kylara A. Papenfuss and Brent L. Black
) on fruit size, fruit quality, and yield of ‘Montmorency’ tart cherry. Materials and Methods The trial was conducted in 2007 and 2008 in a commercial tart cherry orchard ( Prunus cerasus L. cv. Montmorency on Mahaleb rootstock) planted in 1994
Yufei Xu*, Eric Hanson, James Flore and Wayne Loescher
In Michigan boron (B) deficiencies in sour cherry have resulted in routine use of B sprays to enhance fruit set and increase fruit yield. However, field observations indicate that high B levels are associated with premature softening, making fruit unacceptable for processing. Our fertilization studies show that fruit B levels are higher, but B generally has little or no effect on fruit size, maturity, color, or pull force. However, at some locations, B applications increase the number of soft fruit, especially when harvest is delayed well after the optimum maturity date (as indicated by pull force). B-induced yield increases can be achieved without inducing excessive fruit softening by careful monitoring of fruit maturation and prompt harvest. Leaf and fruit B levels will be presented.
J.A. Beaver and A.F. Iezzoni
Inheritance for seven enzyme loci was determined in seeds produced from crosses and self-pollinations involving four sour cherry parents and one open-pollinated ground cherry (P. fruticosa Pall.) parent. Segregation data were used to identify allozymes and determine whether sour cherry is a naturally occurring allo- or autotetraploid. Three allozymes were identified at the 6-Pgd-1 locus, and two were identified at each of the following loci: Pgi-2, Lap-1, Adh-1, Idh-2, Pgm-2, and 6-Pgd-2. Segregating allozyme patterns for the diagnostic loci Idh-2, Pgm-2, 6-Pgd-1, and 6-Pgd-2 tit disomic inheritance models and thus confirmed the allotetraploid hypothesis for sour cherry. Chi-square tests of independence between loci indicated that Pgi-2, Adh-1, Idh-2, 6-Pgd-1, and 6-Pgd-2 were not linked.
Barrett R. Gruber, Libby R.R. Davies and Patricia S. McManus
The fungus Blumeriella jaapii [anamorph Phloeosporella padi (Lib.) Arx] incites cherry leaf spot (CLS), a serious disease of tart cherry ( Prunus cerasus ) in the Great Lakes region of North America ( Jones, 1995 ) and Europe ( Annesi et al
Desmond R. Layne and J.A. Flore
A series of experiments were conducted with one-year-old potted sour cherry trees to evaluate the effects of source reduction (removal of 70% of the expanded leaves = Defol.) or source enhancement (continuous illumination = C.L.) on source leaf gas exchange. There was a significant increase in net CO2 assimilation (A) and stomatal conductance (gs) of Defol. within one day in contrast to the non-defoliated control (Cont.). Defol. had lower daily dark respiration rates (Rd) and higher A values throughout the 14 h diurnal photoperiod than Cont. Defol. had daily assimilation rates 50% higher than Cont. in as early as 3 days. One month later, specific leaf weight, leaf chlorophyll and A was higher in Defol. Non-defoliated plants were also placed under either a 14 h photoperiod (Cont.) or a 24 h photoperiod (24h). A of 24h was reduced from Cont. by 50% after one day. The diurnal response of A in Cont. was removed when plants were put in C.L. Following 7 days in C.L., 70% defoliation of 24h plants resulted in a complete recovery from photosynthetic inhibition within 48 hours. The short-term effects of source manipulation on photochemical and carboxylation efficiencies, photorespiration and stomatal limitations will also be addressed.
A. Kahn, A.F. Iezzoni, S. Kalisz, CA. Mulinix and V. Delasalle
The number of flowers produced by sour cherry greatly exceeds the number of fruits developed. Two hypotheses to explain this disparity were investigated: (1) pollen may be limiting, and (2) a large flower display is important for pollinator attraction. Self-incompatibility, which is common in sour cherry, was considered. Fruit set, floral morphology, and flower density were measured on 18 sour cherry selections, both self-compatible and self-incompatible (SI), in the MSU sour cherry germplasm collection following open- and bulk-pollination. Although supplemental hand pollination resulted in a significant increase in fruit set, the final fruit set was still low (18% vs 14%) indicating that lack of pollination alone was insufficient to account for the low fruit set. The SI selections had significantly larger flower cups, pistil/petal size ratio, and more flowers/branch cross-sectional area suggesting that flower display may have an increased role in pollinator attraction in the SI selections. These results will be discussed in relation to 2 additional hypotheses: insufficient maternal resources and genetic factors resulting in pre- or post-zygotic selection.
Vladislav Ognjanov, Maja Miodragović, Goran Barać, Dejan Prvulović, Mirjana Ljubojević, Jovana Dulić and Dušica Dorić
, Kelleriis 14, Oblačinska, and sweet cherry: wild accession PA_2007 and ‘Bigerreau Hatif Burlat’. The position of ‘Prima’ ( Fig. 1 ) in relation to Prunus cerasus and Prunus avium samples is in agreement with its potential hybrid origin between these two