Instituto Ncionl de Investigción y Tecnologí Agrri y Alimentri (INIA) Spnish Journl of Agriculturl Reserch 9(), 554-564 Aville online t www.ini.es/sjr ISSN: 695-97-X eissn: 7-99 Posthrvest qulity nd chilling injury of plums: enefits of -methylcyclopropene A. P. Cndn *, J. Grell nd C. Lrrigudiere INTA Alto Vlle, C.C. 78. 833 Generl Roc (Río Negro). Argentin UdL-IRTA Center. XRTA. Rovir Roure, 9. 598 Lleid. Spin Astrct The im of this work ws to evlute the effect of -methylcyclopropene (-MCP) tretment on the development of chilling injury (CI) symptoms in four plum cultivrs nd to determine the reltionship etween the climcteric ehvior of the cultivr nd its sensitivity to this disorder. Significnt differences in ripening pttern were found etween the cultivrs fter long-term storge. Among the climcteric cultivrs, Royl Zee plums showed higher ethylene production rte thn Lind Ros nd Frir cultivrs. On the other hnd, the Angeleno cultivr ehved s suppressed climcteric type. The development of trnslucency symptoms ws higher in Royl Zee thn in Lind Ros nd Frir plums, nd ws lmost sent in the suppressed climcteric cultivr. -MCP tretment significntly reduced ethylene production nd the percentge of fruit ffected y trnslucency in ll climcteric cultivrs. This tretment lso delyed the ripening of the fruit during shelf life. In contrst, -MCP tretment did not ffect the qulity of Angeleno plums. Collectively these results suggest tht the development of chilling injury in plums is relted to the climcteric ehvior of the cultivr nd demonstrted the eneficil effects of -MCP mintining plum qulity during storge. Additionl key words: cold storge; ethylene production; firmness; Prunus slicin; ripening pttern; trnslucency Resumen L clidd postcosech y los dños por frío en ciruels: eneficios del -metilciclopropeno El ojetivo de este trjo fue evlur el efecto del trtmiento con -metilciclopropeno (-MCP) sore el desrrollo de los síntoms de dños por frío (DF) en cutro cultivres de ciruel y determinr l relción entre el ptrón de mdurción de los cultivres y su sensiilidd este desorden. Se encontrron diferencis significtivs en el ptrón de mdurción de los cultivres después de un lmcenmiento lrgo plzo. Entre los cultivres climtéricos, Royl Zee mostró un ts de producción de etileno superior l de los cultivres Lind Ros y Frir. Por otr prte, el cultivr Angeleno presentó un comportmiento climtérico suprimido. El desrrollo de síntoms de trnsprenci fue myor en Royl Zee que en Lind Ros y Frir, y csi usente en el cultivr climtérico suprimido. El trtmiento con -MCP redujo significtivmente l producción de etileno y el porcentje de frutos fectdos por l trnsprenci en todos los cultivres climtéricos. Este trtmiento tmién retrsó l mdurción de l frut durnte l vid en estnte. En cmio, el trtmiento -MCP no fectó l clidd de ciruels Angeleno. En conjunto, estos resultdos sugieren que el desrrollo de DF en ciruels está relciondo con el comportmiento climtérico del cultivr y demuestrn los efectos eneficiosos del trtmiento -MCP sore l clidd de ls ciruels durnte el lmcenmiento. Plrs clve dicionles: firmez; frigoconservción; ptrón de mdurción; producción de etileno; Prunus slicin; trnsprenci. Introduction High softening rtes nd susceptiility to chilling injury re the min fctors limiting plums commercil life (Tylor et l., 993). Refrigertion is currently the most widely-used technology to reduce fruit softening, eing tempertures elow C ut ove freezing point the most suitle (Crisosto et l., 999). However, * Corresponding uthor: pcndn@correo.int.gov.r Received: 6-7-; Accepted: 5-4-. Arevitions used: CI (chilling injury), MACC (-mlonyl-minocyclopropne--croxylic cid), SSC (solule solid content), TA (titrtle cidity), -MCP (-methylcyclopropene).
Qulity nd chilling injury of different plum cultivrs: enefits of -methylcyclopropene 555 long-term storge under these conditions promotes the development of chilling injury (CI) symptoms such s flesh trnslucency nd rowning. Symptoms usully pper during the ripening period t C, with consumers who detect this prolem nd complin. Flesh trnslucency is one of the most frequently oserved symptoms in plums; it presents itself s trnslucent nd geltinous re round the stone, lso chrcterized y loss of juiciness (Tylor et l., 993). The physiologicl sis of CI in plums remins to e etter explined. According to Lyons (973), CI is primrily relted to modifictions in memrne permeility ssocited with memrne-lipid trnsition from flexile liquid-crystlline to solid-gel structure. This first event would led to cscde of secondry events, resulting in loss of regultory control nd metolism imlnce, cell utolysis, nd finlly the development of vriety of chilling symptoms (Wng, 989). Flesh trnslucency is lso ssocited to loss of memrne permeility ut lso to n increse in solule pectin tht forms gel in the intercellulr spces cusing the trnslucency symptoms (Tylor et l., 993). Previous study (Lrrigudière et l., 9) hs demonstrted tht CI symptoms in Lrry Ann plums re proly not cused y n oxidtive stress, ut relted to chnges in ethylene metolism nd especilly in the levels of -mlonyl-minocyclopropne--croxylic cid (MACC). In generl, ethylene hs een relted to the development or worsening of different physiologicl disorders ssocited to chilling injury (Kder, 985). -methylcyclopropene (-MCP), n inhiitor of ethylene ction, is effective to reduce the ppernce of chilling injury in pinepples (Selvrjh et l., ) nd in different vocdo cultivrs (Pesis et l., ). This tretment cn lso reduce the incidence of trnslucency in Blckmer (Cndn nd Clvo, 5), Fortune (Menniti et l., 6) nd Lrry Ann (Cndn et l., 8) plums cultivrs. However, this effect cnnot e generlized, s oth susceptiility to chilling injury (Crisosto et l., 999; Cndn et l., 8) nd response to -MCP tretment (Adi et l., 998; Mrtínez-Romero et l., 3; Vlero et l., 5) re cultivr-dependent. The im of this work ws to evlute the effect of -MCP tretment on the development of CI symptoms in four plum cultivrs nd to determine the reltionship etween the climcteric ehvior of the cultivr nd its sensitivity to this disorder. Mteril nd methods Plnt mteril Jpnese plums (Prunus slicin L.) of Royl Zee, Lind Ros, Frir nd Angeleno cultivrs were hrvested from commercil orchrd in Río Negro (Argentin), ccording to fruit firmness. The fruit were immeditely tken to the lortory, where mturity t hrvest ws determined on 3 repetitions of fruit. Fruit of two homogeneous lots from ech cultivr were treted with (Control) or.4 µl L of -MCP for 4 hours during fruit-cooling. The fruits were stored t C nd 9 % RH for 3 nd 5 dys nd the qulity evluted fter removl from the chmer nd fter 3 nd 7 dys of shelf life t C on 3 repetitions of fruit ech. Ethylene production Ethylene production rte (µl kg h ) ws determined right fter hrvest nd fter storge on 3 repetitions of 6 fruit, during dys or until the climcteric mximum ws reched. The fruit were weighed nd enclosed in 3-L jrs for 3 min t C nd then, ml smple ws extrcted from the hedspce. The smple ws nlysed with gs chromtogrph (GC-4A, Shimdzu, Jpn) equipped with n lumin column (4 C) nd FID detector ( C). Helium ws used s crrier gs. Firmness, solule solids content (SSC), titrtle cidity (TA) nd epidermis color Flesh firmness ws determined with n electronic fruit texture nlyzer (FTA-GS4, Güss, South Afric) with n 8 mm-dimeter plunger, on oth cheeks of the fruit fter skin removl. Two slices of flesh were tken from ech fruit nd juiced to determinte SSC (%) with digitl refrctometer (PAL-, Atgo, Jpn) nd TA (%) y titrtion of ml of juice with. N NOH to ph of 8.. The epidermis color ws determined i) t hrvest, visully s color coverge (%) nd ii) fter storge, with tristimulus colorimeter (CR-3, Minolt, Jpn), on two well-colored res on ech fruit fter removing the epicuticulr wx. Dt re expressed in coordintes L*, * nd *, used to clculte hue nd chrom.
556 A. P. Cndn et l. / Spn J Agric Res () 9(), 554-564 Flesh color nd chilling injury symptoms Flesh color nd chilling injury (CI) development were ssessed visully y cutting ech fruit on hlf long the equtoril xis. A 4-grde visul scle ccording to the percentge of flesh colored or injured ws used: Uninjured (%), G (up to 5%), G (5-5%), G 3 (5-%) nd G 4 (-%). Intensity of colortion nd severity of CI were clculted s the totl numer of fruit in ech grde multiplied y the grde nd divided y the totl of injured fruit. Chilling injury ws lso expressed s percentge of ffected fruits. Sttisticl nlysis All dt otined from the tril were nlysed using ANOVA, crried out with Infostt/Professionl v.6p.. Tretments were compred for ech storge nd shelf life period nd then were sujected to men seprtion y Tuckey test (.5). The lest significnt differences (LSD) etween tretments were clculted. Results Fruit chrcteristics t hrvest The fruit were hrvested t the optimum mturity, ccording to locl recommended firmness vlues. Royl Zee ws firmer (53,4 N) thn the other cultivrs which re recommended to void over-ripeness during storge. Lind Ros nd Frir were hrvested t middle firmness vlues (4-45 N) while Angeleno ws the less firm cultivr t hrvest (34,8 N). For ll the cultivrs, the greter the firmness t hrvest, the higher cidity nd the lower solule solids nd color coverge ws oserved (Tle ). Ethylene production t C during ripening fter hrvest differed significntly mong plum cultivrs. Royl Zee presented rpid increse in ethylene production, reching mximum of 98.5 µl kg h fter 9 dys t C. Lind Ros nd Frir did not rech cler climcteric pek ut presented slow increse in ethylene production with mximum vlues of. µl kg h nd 7.3 µl kg h fter 7 nd dys t C, respectively. Finlly, ethylene production of Angeleno remined stedy nd under µl kg h throughout the study period (Fig. ). Effect of cold storge nd -MCP on ethylene production The Royl Zee plum fruit presented rpid increse in ethylene production when removed from the cold storge chmer, ut t lower rtes nd in fewer dys thn fter hrvest (Fig. ). -MCP tretment significntly delyed the increse of ethylene production fter 3 dys of storge nd reduced the mximum of the climcteric fter 3 nd 5 dys of storge. After storge t C, Lind Ros nd Frir plums presented n increse in ethylene production cpcity compred to the vlues oserved t hrvest, nd control Ethylene (μl kg h ) 5 5 5 5 Time t C (dys) Figure. Evolution of ethylene production right fter hrvest in Royl Zee ( ), Lind Ros ( ), Frir ( ) nd Angeleno ( ) plums. Verticl rs represents the stndrd devition, for three smples of 6 fruit ech. Tle. Mturity indexes t hrvest of Royl Zee, Frir, Lind Ros nd Angeleno plums Indexes Royl Zee Lind Ros Frir Angeleno Weight (g) 64.73 ±.95 98.58 ± 5.7 9. ±.6 87.34 ± 4.9 Firmness (N) 53.46 ± 4.7 4.6 ±.36 45.8 ±.3 34.84 ±. Solule solids content (%).7 ±.5 4.7 ±.7.3 ±.5 5. ±. Titrtle cidity (%).3 ±.3.63 ±..6 ±.4.6 ±.7 Color coverge (%) 8.35 ±.74 8.9 ± 7.4 95. ± 3.5 ±. Ech vlue represents the verge ± stndrd devition, for three smples of fruit ech.
Qulity nd chilling injury of different plum cultivrs: enefits of -methylcyclopropene 557 Ethylene (μl kg h ) 3 dys t C 5 dys t C LSD = 7. LSD = 7.8 8 8 6 6 4 4 7 4 7 4 6 6 5 5 Firmness (N) 4 3 LSD = 5.87 4 3 LSD = 4.87 3 4 5 6 7 3 4 5 6 7.5.5 LSD =.3 TA (%).5 LSD =.8.5 3 4 5 6 7 3 4 5 6 7 3 LSD =.6 3 LSD = 3.93 Color (chrom) 3 4 5 6 7 Time t ºC (dys) 3 4 5 6 7 Time t ºC (dys) Figure. Evolution of ethylene production, firmness, titrtle cidity nd epidermis color during shelf life t C, fter 3 nd 5 dys of storge t C in control ( ) nd -MCP-treted ( ) Royl Zee plums. Verticl rs show LSD (Tukey,.5) of the set of points presented in ech grph. fruit exhiited cler climcteric pek during shelf life t C. -MCP tretment delyed the occurrence of the climcteric pek in the Lind Ros cultivr oth fter 3 nd 5 dys of storge t C (Fig. 3). A similr ehvior ws found for the Frir cultivr with n inhiition of climcteric ethylene production fter 3 dys of storge (Fig. 4). Low-temperture storge did not ffect the ethylene production rtes in Angeleno cultivr, which remined lower thn 3 µl kg h throughout the entire study period nd without ny differences etween control fruit nd -MCP-treted fruit (Fig. 5).
558 A. P. Cndn et l. / Spn J Agric Res () 9(), 554-564 Ethylene (μl kg g ) 8 6 4 5 4 3 dys t C 5 dys t C LSD = 9. LSD =.5 8 6 4 7 4 7 4 5 LSD = 4.98 LSD =.7 4 Firmness (N) 3 3 3 4 5 6 7 3 4 5 6 7.5.5 TA (%).5 LSD =.4.5 LSD =. Color (chrom) 4 3 3 4 5 6 7 LSD = 3.37 4 3 3 4 5 6 7 LSD =.44 3 4 5 6 7 3 4 5 6 7 Time t C (dys) Time t C (dys) Figure 3. Evolution of ethylene production, firmness, titrtle cidity nd epidermis color during shelf life t C, fter 3 nd 5 dys of storge t C in control ( ) nd -MCP-treted ( ) Lind Ros plums. Verticl rs show LSD (Tukey,.5) of the set of points presented in ech grph. Effect of cold storge nd -MCP on fruit ripening As for ethylene production, the evolution of mturity indexes during shelf life ws cultivr dependent. Royl Zee control fruit softened rpidly while -MCPtreted fruit presented significntly higher firmness vlues up to 3 dys of shelf life ut not fter 7 dys of shelf life t C (Fig. ). Lind Ros nd Frir control fruit rpidly lost firmness during shelf life, while -MCP-treted fruit softened more slowly nd mintined significntly higher firmness vlues up to 7 dys of shelf life, oth fter 3 nd 5 dys of cold storge (Figs. 3 nd 4). The Angeleno cultivr presen-
Qulity nd chilling injury of different plum cultivrs: enefits of -methylcyclopropene 559 3 dys t C 5 dys t C Ethylene (μl kg h ) 8 6 4 LSD =.4 8 6 4 LSD =. 5 7 4 5 7 4 4 LSD = 4.87 4 LSD = 4.58 Firmness (N) 3 3 3 4 5 6 7 3 4 5 6 7.5.5 TA (%) Color (chroml).5 5 5 LSD =.4 3 4 5 6 7 LSD =..5 5 5 LSD =.6 3 4 5 6 7 LSD =. 3 4 5 6 7 Time t C (dys) 3 4 5 6 7 Time t C (dys) Figure 4. Evolution of ethylene production, firmness, titrtle cidity nd epidermis color during shelf life t C, fter 3 nd 5 dys of storge t C in control ( ) nd -MCP-treted ( ) Frir plums. Verticl rs show LSD (Tukey,.5) of the set of points presented in ech grph. ted very slow softening during shelf life, without ny significnt differences oserved etween control fruit nd -MCP-treted fruit (Fig. 5). The fruit presented decrese in TA during cold storge nd susequent shelf life, except for the Angeleno cultivr. -MCP tretment delyed TA loss during shelf life nd significnt differences were found fter 3 dys of shelf life for Royl Zee plums, nd fter 7 dys of shelf life for Lind Ros nd Frir plums (Figs., 3 nd 4). SSC (%) remined stedy throughout storge nd shelf life nd ws not ffected y -MCP tretment in ny of the cultivrs (dt not shown). The Angeleno cultivr did not show significnt epidermis color chnges nd no differences were oserved etween control fruit nd -MCP-treted fruit
56 A. P. Cndn et l. / Spn J Agric Res () 9(), 554-564 3 dys t C 5 dys t C Ethylene (μl kg h ) 8 6 4 LSD =. 8 6 4 LSD =.5 5 7 4 5 7 4 4 4 Firmness (N) 3 LSD = 4.73 3 LSD = 4.4 3 4 5 6 7.5.5 3 4 5 6 7 TA (%).5 LSD =.8.5 LSD =. 3 4 5 6 7 3 4 5 6 7 5 5 LSD =.99 LSD =.98 Color (chrom) 5 5 3 4 5 6 7 Time t C (dys) 3 4 5 6 7 Time t C (dys) Figure 5. Evolution of ethylene production, firmness, titrtle cidity nd epidermis color during shelf life t C, fter 3 nd 5 dys of storge t C in control ( ) nd -MCP-treted ( ) Angeleno plums. Verticl rs show LSD (Tukey,.5) of the set of points presented in ech grph. (Fig. 5). In contrst, the epidermis color chnged from red to purple in Royl Zee nd Lind Ros plums, nd from purple to lck in Frir. These color chnges during storge of plums were reflected y the chrom etter thn y hue (dt not shown). As visul color chnged, significnt decrese in chrom vlues ws oserved during shelf life. -MCP-treted fruit mintined higher chrom vlues during shelf life fter 3 dys of storge in Royl Zee plums nd fter 3 nd 5 dys of storge in Lind Ros nd Frir plums (Figs., 3, 4). As oserved for epidermis color, ll cultivrs except Angeleno developed red flesh color (Tle ). The effect of -MCP on these chrcteristics ws lower in Royl Zee thn in Lind Ros plums, nd in the ltter thn in Frir plums, in which -MCP totlly inhiited
Qulity nd chilling injury of different plum cultivrs: enefits of -methylcyclopropene 56 Tle. Effect of -MCP tretment on red flesh color development (intensity: to 4) in different plum cultivrs stored 3 nd 5 dys t C nd exposed to, 3 nd 7 dys of shelf life t C 3 dys t C 5 dys t C 3 7 3 7 Royl Zee Control.7.3.74.9.4.6 -MCP..38.47...45 Lind Ros Control.3.3 3.83..43.3 -MCP...33.7.9.35 Frir Control.5..7. 3.3 -MCP....33.67 Men seprtion ws crried out using Tukey s test (.5). the development of red flesh color up to 5 dys of storge t C. Effect of cold storge nd -MCP on chilling injury (CI) Flesh trnslucency ws the most importnt CI symptom oserved in this work. In Royl Zee plums, CI symptom ws present fter 3 dys of storge t C oth in control fruit nd in -MCP-treted fruit, nd incresed s the storge ws extended nd fter 3 dys of shelf life irrespective of the tretment (Fig. 6). Flesh trnslucency ffected Lind Ros nd Frir control fruits during shelf life especilly fter 5 dys of storge t C (Figs. 6 nd 6c). -MCP tretment completely inhiited CI occurrence in oth cultivrs fter 3 dys of storge nd significntly reduced the percentge of injured fruit even fter 7 dys of shelf life. No trnslucency symptoms were oserved in the Angeleno plum fruit in ll the tests performed even without -MCP tretment. The severity of trnslucency symptoms ws.5 nd in Royl Zee,.5 nd in Lind Ros nd nd in Frir plums t the end of shelf life nd following 3 nd 5 dys of storge, respectively. As oserved for percentge of injured fruit, -MCP tretment reduced the symptom s severity in Lind Ros nd Frir plums ut not in Royl Zee plums (dt not shown). Discussion Ripening pttern nd response to -MCP Plums re trditionlly considered s climcteric fruit, ut in the lst few yers suppressed climcteric cultivrs hve een identified (Adi et l., 997; Zuzung et l., ). According to this work Royl Zee plums re considered climcteric nd show rpid increse in ethylene production during ripening (Dong et l., ). In contrst, Angeleno plums mintined very low ethylene production throughout the posthrvest period, which is in greement with the oservtions of Holcroft et l. (), who define this cultivr s suppressed climcteric. Lind Ros nd Frir cultivr fruit presented low ethylene production rte fter hrvest, ut typiclly climcteric ripening pttern ws oserved fter 3 nd 5 dys of storge t C. These results suggest tht these cultivrs need low tempertures to strt their climcteric ethylene synthesis, s oserved in Songold nd Lrry Ann cultivrs (Tylor et l., 993; Cndn et l., 8). Such ehvior hs lso een oserved in other species like nectrines (Brecht nd Kder, 984), pples (Lrrigudière et l., 993, 997) nd pers (Lelièvre et l., 997). The -MCP tretment reduced ethylene production nd this effect ws less significnt in Royl Zee thn in Lind Ros plums nd thn in Frir plums. This suggests tht, mong climcteric cultivrs, the higher ethylene production rte t hrvest, the less
56 A. P. Cndn et l. / Spn J Agric Res () 9(), 554-564 ) ) Trnslucency (%) 5 5 3 dys t C c c c 3 7 5 5 5 dys t C c c 3 7 c) Trnslucency (%) 5 5 3 7 5 5 3 7 Trnslucency (%) 5 5 3 7 Time t C (dys) 5 5 c c 3 7 Time t C (dys) Figure 6. Percentge of fruit ffected y flesh trnslucency during shelf life t C fter 3 nd 5 dys of storge t C in control fruit (grey rs) nd -MCP-treted fruit (white rs) of Royl Zee (), Lind Ros () nd Frir (c) plums. Within ech grph, columns with different letters differ significntly ccording to the LSD vlue (Tukey,.5). c c significnt is the response to -MCP tretment. This result ws in ccordnce to those oserved y Vlero et l. (5) nd showed tht the -MCP dose required to control ripening in plum should e djusted to the cultivr (Mrtínez-Romero et l., 3). In the cse of the suppressed climcteric Angeleno cultivr, -MCP tretment ffected neither ethylene production nor mturity indexes (such s firmness, TA nd epidermis color). Such reltionship hs een oserved in other cultivr nd it ws hypothesized tht ripening chnges were not relted to ethylene production in suppressed climcteric cultivrs (Adi et l., 997). However, this result must e interpreted with cution, s other uthors hve oserved tht -MCP tretment reduces softening rtes in these types of cultivrs (Vlero et l., 5; Menniti et l., 6). Effects of -MCP tretment on fruit qulity In generl it is recognized tht -MCP tretment reduced firmness loss in plum (Dong et l., ; Argent et l., 3; Mrtínez-Romero et l., 3; Slvdor et l., 3; Vlero et l., 5; Cndn et l., 6). In ccordnce with this ide, low ethylene production in Angeleno fruit coincides with lower softening rte thn tht oserved in the other cultivrs studied in this work. This result ws oserved y other uthors (Holcroft et l., ) nd showed tht flesh softening is n ethylene-dependent process (Lelièvre et l., 997). Softening is known to e ssocited with the fruit s cell wll degrdtion process, nd it hs recently een demonstrted tht -MCP reduces cell wll-degrding enzymes ctivity, helping to mintin the plums firmness (Khn nd Singh, 7).
Qulity nd chilling injury of different plum cultivrs: enefits of -methylcyclopropene 563 Royl Zee, Lind Ros nd Frir plums lost TA s the fruit s storge nd shelf life extended, due to the utiliztion of orgnic cids s sustrte in tissue respirtion. -MCP-treted fruit mintined higher TA vlues, which could e due to decrese in respirtion rtes, s oserved in other cultivrs (Dong et l., ; Argent et l., 3; Slvdor et l., 3). On the other hnd, mny previous studies showed tht -MCP tretment delys epidermis color chnges in plums (Dong et l., ; Slvdor et l., 3) nd tht such effect is cultivr-dependent (Vlero et l., 5). This work showed -MCP tretment delyed the epidermis color chnge (chrom) in climcteric cultivrs ut not ffected the color in the suppressed climcteric cultivr. Besides, -MCP tretment significntly reduced red flesh color development in Frir nd Lind Ros plums, coinciding with oservtions mde in Letiti (Argent et l., 3) nd Blckmer (Cndn et l., 6) plums. Nonetheless, Dong et l. () oserved tht the ppliction of -MCP incresed the development of red pigments in the flesh of Royl Zee plums, ut such ehvior ws not oserved in this work. According to firmness vlues recommended for plum consumption (Neri, 3), the time needed to ripen vried etween 3 nd 5 dys for Royl Zee, nd etween 5 nd 6 dys for Lind Ros nd Frir. -MCP tretment extended the fruit s shelf life y 4 to 7 dys in Royl Zee nd more thn 7 dys in Lind Ros nd Frir similrly thn for Blckmer plums (Cndn et l., 6). Besides texture, the plums orgnoleptic qulity is lso closely relted to sugr (SSC) nd cid (TA) contents (Crisosto et l., 4). This nd other reserch ppers stte tht -MCP tretment does not ffect SSC ut mintins higher TA vlues, which might ffect the fruit s finl sensory qulity (Dong et l., ; Argent et l., 3; Slvdor et l., 3; Cndn et l., 6). When Royl Zee fruits reched their firmness consumption, the vlues of AT were similr in oth controls nd in treted fruits. Moreover, these vlues re consistent with those recommended y Crisosto et l. (7) for the consumption of this vriety. The sme my e expected to occur with the other cultivrs studied, ut further studies re necessry to ffirm it. Effect of -MCP tretment on chilling injury According to the findings presented in this work, the percentge of fruit ffected y trnslucency ws higher in cultivrs tht exhiited higher ethylene production rte. In ccordnce with this ide, the Angeleno cultivr fruit tht produced low ethylene throughout the entire experimentl period did not develop CI symptoms. These results show the reltionship tht exist etween ethylene production nd fruit susceptiility to CI nd sustins the hypothesis proposed in previous reserch (Cndn et l., 8). Moreover, -MCP tretment significntly reduced the ppernce of trnslucency symptoms nd even completely eliminted these symptoms in Lind Ros nd Frir cultivrs fter 3 dys of storge. Similr results were lso oserved in Blckmer (Cndn nd Clvo, 5), Lrry Ann (Cndn et l., 8) nd Fortune (Menniti et l., 6) plums. Collectively, these results support the ide tht ethylene prticiptes in the development of chilling injury symptoms in climcteric plums (Cndn et l., 8) nd tht -MCP is useful tool for chilling injury control in this species. They lso suggest tht erly ripening cultivrs might e more susceptile to chilling injury thn lte ripening cultivrs. Acknowledgements This reserch ws supported y INTA Alto Vlle, Argentin (PNFRU-539). The uthors grtefully cknowledge the Rohm nd Hs Compny for providing Smrtfresh TM product. References ABDI N., HOLFORD P., McGLASSON W.B., MIZRAHI Y., 997. Ripening ehviour nd responses to propylene in four cultivrs of Jpnese type plums. Posthrvest Biol Technol, -34. ABDI N., McGLASSON W.B., HOLFORD P., WILLIAMS M., MIZARAHI Y., 998. Reponses of climcteric nd suppressed climcteric plums to tretment with propylene nd -methylcyclopropene. Posthrvest Biol Technol 4, 9-39. ARGENTA L.C., KRAMMES J.G., MEGGUER C.A., AMARANTE C.V., MATTHEIS J., 3. Ripening nd qulity of Letiti plums following hrvest nd cold storge s ffected y inhiition of ethylene ction. Pesq Agropec Brs 38, 39-48. BRECHT J.K., KADER A.A., 984. Regultion of ethylene production y ripening nectrine fruit s influences y ethylene nd low temperture. J Am Soc Hort Sci 9, 869-87.
564 A. P. Cndn et l. / Spn J Agric Res () 9(), 554-564 CANDAN A.P., CALVO G., 5. Tretment with -MCP my reduce chilling injury in cold stored Blckmer plums. 9 th Interntionl Controlled Atmosphere Reserch Conference. Est Lnsing, Michign, USA, July 5-. pp. 9. CANDAN A.P., GRAELL J., CRISOSTO C., LARRIGAUDIÈRE C., 6. Improvement of storility nd shelf life of Blckmer plums treted with -methylcyclopropene. Food Sci Technol Int 5, 437-444. CANDAN A.P., GRAELL J., LARRIGAUDIÈRE C., 8. Roles of climcteric ethylene in the development of chilling injury in plums. Posthrvest Biol Technol 47, 7-. CRISOSTO C.H., MITCHELL F.G., JU Z., 999. Susceptiility to chilling injury of pech, nectrine, nd plum cultivrs grown in Cliforni. HortSci 34, 6-8. CRISOSTO C., GARNER D., CRISOSTO G., BOWERMAN E., 4. Incresing Blckmer plum (Prunus slicin L.) consumer cceptnce. Posthrvest Biol Technol 34, 37-44. CRISOSTO C.H., CRISOSTO G.M., ECHEVERRÍA G., PUY J., 7. Segregtion of plum nd pluot cultivrs ccording to their orgnoleptic chrcteristics. Posthrvest Biol Technol 44, 7-76. DONG L., LURIE S., ZHOU H.W.,. Effect of - methylcyclopropene on ripening of Cnino pricots nd Royl Zee plums. Posthrvest Biol Technol 4, 35-45. HOLCROFT D.M., KRUGER L., COOK N.C.,. Climcteric nd suppressed climcteric ripening ptterns in plums: implictions for posthrvest hndling. South Africn Fruit Journl, Jun-Jul, 4-7. KADER A.A., 985. Ethylene-induced senescence nd physiologicl disorders in hrvested horticulturl crops. HortScience (), 54-57. KHAN A.S., SINGH Z., 7. -MCP regultes ethylene iosynthesis nd fruit softening during ripening of Tegn Blue plum. Posthrvest Biol Technol 43, 98-36. LARRIGAUDIÈRE C., VENDRELL M., 993. Cold-induced ctivtion of -minocyclopropne--croxilic cid metolism in rewrmed Grnny Smith pples: consequences on ripening. Sci Hort 55, 63-7. LARRIGAUDIÈRE C., GRAELL J., SALAS J., VENDRELL M., 997. Cultivr differences in the influence of short period of cold storge on ethylene iosynthesis in pples. Posthrvest Biol Technol, -7. LARRIGAUDIÈRE C., CANDAN A.P., UBACH D., GRAELL J., 9. Physiologicl response of Lrry Ann plums to cold storge nd -MCP tretment. Posthrvest Biol Technol 5, 56-6. LELIÈVRE J.M., LATCHÉ A., JONES B., BOUZAYEN M., PECH J.C., 997. Ethylene nd fruit ripening. Physiol Plnt, 77-739. LYONS J.M., 973. Chilling injury in plnts. Ann Rev Plnt Physiol 4, 445-466. MARTÍNEZ-ROMERO D., DUPILLE E., GUILLÉN F., VALVERDE J.M., SERRANO M., VALERO D., 3. - Methylcyclopropene increses storility nd shelf life in climcteric nd nonclimcteric plums. J Agric Food Chem 5, 468-4686. MENNITI A.M., DONATI I., GREGORI R., 6. Responses of -MCP ppliction in plums stored under ir nd controlled tmospheres. Posthrvest Biol Technol 39, 43-46. NERI F., 3. Influence of mturity stge nd ripening on sensory qulity of peches, nectrines nd plums. Eufrin Workshop on Fruit Qulity, Bologn, June -4. pp. 4-4. PESIS E., ACKERMAN M., BEN-ARIE R., FEYGENBERG O., FENG X., APELBAUM A., GOREN R., PRUSKY D.,. Ethylene involvement in chilling injury symptoms of vocdo during cold storge. Posthrvest Biol Technol 4, 7-8. SALVADOR A., CUQUERELLA J., MARTÍNEZ-JÁVEGA J.M., 3. -MCP tretment prolongs posthrvest life of Snt Ros plums. J Food Sci 68, 54-5. SELVARAJAH S., BAUCHOT A.D., JOHN P.,. Internl rowning in cold-stored pinepples is suppressed y posthrvest ppliction of -methylcyclopropene. Posthrvest Biol Technol 3, 67-7. TAYLOR M.A., JACOBS G., RABE E., DODD M.C., 993. Physiologicl fctors ssocited with overripeness, internl rekdown nd gel rekdown in plums stored t low temperture. J Hort Sci 68, 85-83. VALERO D., GUILLÉN F., VALVERDE J.M., MARTÍNEZ- ROMERO D., CASTILLO S., SERRANO M., 5. - MCP use in Prunus sp. to mintin fruit qulity nd extend shelf life during storge: comprtive study. Act Hortic 68, 933-94. WANG C.Y., 989. Chilling injury of fruit nd vegetles. Food Rev Int 5, 9-36. ZUZUNAGA M., SERRANO M., VALERO D., MARTÍNEZ- ROMERO D., RIQUELME F.,. Comprtive study of two plum (Prunus slicin Lindl.) cultivrs during growth nd ripening. Food Sci Technol Int 7, 3-3.