Loose Leaf Lettuce Quality Grown in Two Production Systems

Transcription

1 Loose Lef Lettue Qulity Grown in Two Prodution Systems Luis L.Trvieso Adrin P. Leon, MS. Veroni R. Logegry,Esp. Din Frezz, MS. Angel Chies, D. University of Buenos Aires, Argentin doi: /esj.216.v12n3p55 URL: Astrt Hortiulturl rops hve strong impt on humn nutrition. Lettue is the most importnt lefy vegetle in Argentin nd it is ultivted minly in green elts, in s or open field. The im of this study ws to evlute growth nd phytonutrients onentrtion of lef lettue under nd field prodution. Crop estlishment ws mde from seedlings produed in ommeril. Loose lettue v. Bris ws used for field nd growth. Experimentl design with omplete rndom lok with 4 replites per tretment ws used. Fresh nd dry weights of shoot, numer of leves, olor, sori id, hlorophyll ontent were mesured. Asolute nd reltive growth rte nd ommeril yield were lulted. Lettue grown under system showed, s expeted, higher vlue of fresh nd dry weight, numer of leves, lef re, yield nd solute nd reltive growth rte. Asori id vlue of the leves deresed during lettue growth in oth prodution systems. Chlorophyll ontent ws higher in the ultivtion ut the ntioxidnt pity ws lower in lettue leves from thn the leves grown on open field. Keywords: Lefy vegetle,, sori id, ntioxidnt, hlorophyll Introdution Lettue is lefy vegetle grown troughout the ountry round urn enters nd in speilized res nd it is grown under or field onditions. There is dependene etween rop growth nd wether onditions (Sgli et l., 23). Lettue is trditionlly field grown rop ut 55

2 reently prodution inresed too muh due to high qulity of produt (Mroto, 2). Commeril yields of lettue prodution rnge etween 2-5 tn.h -1 (Ferrtto, 1995). Qulity of hortiulturl produts is evluted in terms of: hygienisnitry, nutritionl, tehnologil nd orgnolepti qulity (Gviol, 1996). Lettue, like other lefy vegetles, is known for its supply of vitmin C, B1, B2, foli id, high in mgnesium nd few sodium (Lee nd Kder, 2). Furthermore, lso ontins mny ntioxidnt ompounds, suh s: rotenoids, polyphenols nd fier (Serfini et l., 22) nd hs signifint quntities of lium nd iron (Romni et l., 22). Mny studies suggest tht phytonutrients hve positive effets in preventing ner, rdiovsulr disese nd reduing the inidene of other hroni disese (Lee nd Aedin, 26). Mny prehrvest ftors n ffet posthrvest qulity nd nutritionl vlue of vegetles (Weston y Brth, 1997). Light nd temperture hve strong influene on hemil omposition of vegetles (Klein nd Perry, 1982). These vritions re due to the ft tht phytonutrients re enoded y lrge numer of genes nd shre iosynthesis pthwys whose regultion is t lest prtilly regulted environmently (Hirsherg 21; Lihtenthler 27; Vogt 21). Vitmin C, inluding sori id nd dehydrosori id, is one of the most importnt ompound ontriuting to nutritionl qulity in mny vegetle rops nd hs numerous iologil tivities in the humn ody (Lee y Kder, 2) nd it is primry soure of dietry ntioxidnts (Mrtínez-Sánhez et l., 28). Climte nd ulturl onditions influene the ontent of vitmin C (Lisiewsk nd Kmieik,1996). Light lso ffet sori id ontent, generlly lower light intensity during growth less sori id ontent in plnt tissues (Hrris, 1975). Lee nd Kder (2) report tht etween prehrvest ftors, genotype, light intensity nd temperture re the most importnt ftors determining finl ontent in vegetles. Lefy vegetles lso ontin severl types of photosyntheti pigments, inluding holorophyll nd rotenoids (Kimur y Rodríguez- Amy, 22). The estruture of these pigments produes speifi olor, whih is one of the ttriutes of visul qulity (Xue y Yng, 29). It is widely known tht the hlorophyll ontent of the lef is n importnt testing prmeter for determine plnt ondition, for exmple, it n e used s n index for plnt produtivity nd photosyntheti potentil (Crter, 1998; Penuels et l., 1995). Furthemore, hlorophyll ontent gives n indiret estimte of nutrient sttus euse muh of the nitrogen is prt of lef hlorophyll (Penuels et l., 1995). However, its ontent is lso losely 56

3 relted to vrious types of stress nd senesene (Crter et l., 1996; Gitelson nd Merzlyk, 1994; Penuels et l., 1995). Mny phenoli ompounds, inluding flvonoids present in lettue, hve een extensively studied euse of its ntioxidnt properties (Altunky et l., 29; Llorh et l., 28). In plnts, they re relted to vrious defense mehnisms, therefore, environmentl ftors suh s light, temperture, humidity, nd other internl nd geneti differenes, nutrients, hormones, et ontriute to its shyntesis (Hhkonen et l., 21). The im of this study ws to evlute if ulture ondition ffet growth nd nutritionl qulity of loose lef lettue. Nutritionl qulity is of gret interest, s this spet is eing inresingly onsidered mong onsumers who re willing to get hortiulturl produts of higher nutritionl qulity, promoting growing demnd. Mteril nd Methods Crop estlishment ws mde with seedlings produed in omeril. Trnsplnt ws performed 4 dys fter sowing in two different systems: nd open field. Cultivtion ws rried out t density of 16 plnts.m- 2 (.25 etween rows nd plnts), fter tht rop mngement ws similr to one ommeril, regulr wtering y hnd to keep the soil with dequte wter supply. Tretments nd experimentl design Loose lettue v. Bris ws used for open field nd rop. Experimentl design with omplete rndom lok with four replites per tretment ws used. Dt olletion ws performed four times during growth period: initil time ( dy, trnsplnt dy) nd 42, 69 nd 97 dys fter trnsplnt. Eh moment three rndomly seleted plnts per replite nd three leves for different position were tken for determintion of sori id, hlorophyll nd ntioxidnt pity. Proedures nd lultions proposed y Hunt (1978, 1982) were used. To determine fresh nd dry weight of the shoot n eletroni lne Sout Pro-SP21 ws used. Dry mtter ws lulted using the following eqution: % Dry mtter (%DM) = (dry weight (g) / fresh weight (g)) * 1 Numer of leves ws reorded ounting the numer of leves lrger thn 2 m nd lef re ws estimted y drwn the perimeter of eh individul lef in A4 pper, trimmed round the perimeter nd finlly sine A4 re nd weight ws known lef re ws lulted. Asolute nd reltive growth rte nd ommeril yield were lulted. Asori id ws mesured ording to omintion of methods proposed y Viente et l. (26) y Kvesitdze et l. (21). Color 57

4 prmeters were mesured y the Hunter L o-ordintes y tristimulurs olorimeter (model CR 3, Minolt Corportion, Jpn) nd CIE stndrd illuminnt D65. The olorimeter ws lirted with stndrd white tile (Y=95.3, x=.3133, y=.3197). Color ws exoressed using L*, * nd * prmeters. Antioxidnt pity ws determined y tehniques dpted from Brnd-Willims et l., (1995); Leong y Shui, (21); nd Lim y Quh, (27). For determintion of totl hlorophyll tehnique used y Willim et l. (1984) ws employed. Dt were nlyzed using nlysis of vrine, using Tukey test t 5% for omprison etween tretments. Infostt sttistil progrm ws used. Results nd Disussion Fresh weight (FW) showed signifint differenes etween the verge vlues of nd field, eing higher in the. Lettue grown in hd higher FW t 69 nd ould e hrvested t tht moment euse they rehed ommeril weight. Lettue grown in rop field hd less FW during the growing stge (Figure 1). These results gree with Mroto (2) who reported tht vegetle prodution tends to inrese prodution levels, following the est onditions of physil environment. Differenes in the growth period our in response to temperture nd rdition. Growth rte is elerted y high tempertures nd higher irrdine (Wien, 1997). Tempertures in the were greter during the rop growth yle, therefore, the growth rte ws higher nd the yle ws redued. Fresh weight (g) field d d Figure1. Fresh weight of lettue in two growing systems (open field nd ) during growth yle (, 42, 69 nd 97 ). Different letters mens signifint differenes. 58

5 Dry weight showed signifint differenes etween growing systems, with higher vlue in. Lettue ultivted on field presented lower dry weight t hrvest (Figure 2). Dry weight (g) d d field Figure 2. Dry weight of lettue growing in two different systems (open field or ). Different letters mens signifint differenes (α=.5). Dry mtter deresed from trnsplnt to hrvest ut with lower perentge in the t hrvest (Figure 3). Stnley (1989) reported tht plnts derese the ontent of dry mtter, vitmin C, potssium, mgnesium, iron nd zin when progresses t their stge of development. Dry mtter (%) field Figure 3. Lettue dry mtter in two systems (open field nd ). Different letters mens signifint differenes (α=,5). 59

6 Plnts ultivted in hd more leves during the growing seson, however the sme numer of leves were rehed in open field system t hrvest (Figure 4) field d d d Numer of leves Figure 4. Numer of leves per plnt in lettue grown in two systems: open field nd. Different letters mens signifint differenes (α=,5). Lef re of lettue in ws signifintly higher thn open field tretment from 42 (Figure 5). Lef re (m 2 ) d d field Figure 5. Lef re of lettue growing in two systems (open field nd ). Different letters mens signifint differene (α=,5). Asolute growth rte showed signifint differene etween prodution system nd time with the highest vlue in the t 69. It ws lso oserved tht field hd no differenes 6

7 from to 69 dys (Figure 6). It my e euse the temperture ws lower for rop growth on open field. Reltive growth rte hd differenes etween systems nd time. Asolute growth rte (g.dy -1 ) field Figure 6. Asolute growth rte of lettue in two growing systems (open field nd ). Lettue yield presented signifint differenes eing lmost twie in (39 T.h -1 ) thn on field (2 T h -1 ). Tle 1. Color prmeters (L*, *, *) of lettue during growing in nd on field Dys fter trnsplnting Prmeter System L* Open Field Greenhouse * Open Field d d Greenhouse * Open Field Greenhouse Different letter mens signifint differene in the sme line nd etween tretments for the sme prmeter. Among the nd open field tretments no signifint differenes for rightness (L *) were reorded. There were signifint differenes etween growing dtes of lettue with lower rightness t 42 dys (L * vlue etween nd on verge). Signifint differenes etween tretments nd smpling dtes for * vlue were found. Higher * (green) ws oserved during trnsplnting nd * vlues were signifintly higher on field t 42, 69 nd 97 dys. No signifint differenes were found for * prmeter. The dte of trnsplnt showed greter vlue ( * = 45.81) thn ny other 61

8 Signifint differenes for estimting totl hlorophyll in lettue leves (p <.1) were found t hrvest eing higher for plnts of (.25 mg.g -1 ) tht open field (.16 mg.g -1 ) (Figure 7). Totl hlorophyll ontent (mg.g -1 ),3,25,2,15,1,5 Trnsplnting Hrvest Figure 7. Totl hloropyll ontent (mg.g -1 ) of lettue in two growing systems (field nd ) t two different moments (trnsplnting nd hrvest). The sori id ontent presented signifint differenes etween tretments. The sori id ontent of lettue ws higher in open field thn in t the eginning of the growing seson ut lower t hrvest. Prehrvest ftors, genotype, light intensity nd temperture re the most importnt fts determining the finl ontent of sori id in vegetles (Lee nd Kder, 2). The limte nd ulturl onditions influene the ontent of vitmin C. Higher ontent of vitmin C to hrvest is expeted with higher light intensity during rop growth (Lisiewsk nd Kmieik, 1996). The dt re onsistent with the literture ited. Signifint differenes were found mong dtes with derese in sori id ontent of lettue leves from trnsplnting to hrvest (Figure 8). This is onsistent with Stnley (1989) who reported tht s the plnt progresses in its development stge, redues the ontent of dry mtter, vitmin C, potssium, mgnesium, iron nd zin. fiel 62

9 Asori id ontent (mg.g -1 ),2,18,16,14,12,1,8,6,4,2 field d d e f Figure 8 Asori id ontent of leves in lettue grown in two systems: open field nd. Different letters mens signifint differene (α=,5). Signifint differenes in ntioxidnt pity were found. Light intensity ws lower in the, so it would hve expeted lower level of ntioxidnt pity. Time lso showed sttistilly signifint differenes (p <.1) eing 69 dys the highest vlue. At the middle of the growing seson (42 dys) field 42 hd the highest vlue of ntioxidnt pity (Figure 9). 2,5 Antioxidnt pity (um.g -1 ) 2 1,5 1,5 field Figure 9. Antioxidnt pity (um.g -1 ) in lettue leves grown in two systems: open field nd Different letters mens signifint differene (α=,5). d e f e 63

10 Conlusion Lettue grown under system showed, s expeted, higher vlue of fresh nd dry weight, numer of leves, lef re, yield nd solute nd reltive growth rte. Asori id vlue of the leves deresed during lettue growth in oth prodution systems. The vlues of hlorophyll nd ntioxidnt pity were higher in the ultivtion. Referenes: 1. Altunky, A., Beker E.M., Gökmen V., nd Skisted L.H. 29. Antioxidnt tivity of lettue extrt (Ltu stiv) nd synergism with dded phenoli ntioxidnts. Food Chemistry 115: Brnd-Willims W., Cuvelier M.E., nd Berset C Use of free rdil method to evlute ntioxidnte tivity. LWT Food Siene nd Tehnology. 28 (1): Crter, G.A., Refletne wvends nd indies for remote estimtion of photosynthesis nd stomtl ondutne in pine nopies. Remote Sensing of Environment. 63 (1): Crter, G.A., Ciul, W.G. nd Miller, R.L., Nrrow-nd refletne imgery ompred with therml imgery for erly detetion of plnt stress. Journl of Plnt Physiology. 148: Ferrtto, J Produión de hortlizs en invernáulo. Cultivo de l lehug. INTA. Curso Distni. Módulo 5: Gviol, S Ftores de mnejo que iniden sore l lidd de ls hortlizs. Avnes en Hortiultur 1 (1): Gitelson, A.A. nd Merzlyk, M.N., Spetrl refletne hnges ssoite with utumn senesene of Aesulus hippostnum L. nd Aer pltnoides L. leves. Spetrl fetures nd reltion to hlorophyll estimtion. Journl of Plnt Physiology. 143 (3): Hrris, R. S Effets of griulturl prties on the omposition of foods. In: Hrris, R.S, Krms, E. (Eds.), Nutritionl Evlution of Food Proessing, 2nd edition. AVI, Westport, CT, p Hhkonen M.; Hopi, A. nd Heinomen, M. 21. Berry Phenolis nd their Antioxidnt Ativity. Journl of Agriulturl nd Food Chemistry. 49 (8): Hirsherg J. 21. Crotenoid iosynthesis in flowering plnts. Current Opinion in Plnt Biology. 4 (3): Hunt, R Plnt growth nlysis. Edwrd Arnold, London. 67 p. 12. Hunt, R Plnt growth urves. The funtionl pproh to plnt growth nlysis. Edwrd Arnold, London. 248 p. 64

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