Gibberellic Acid (GA3), an Influential Growth Regulator for Physiological Disorder Control and Protracting the Harvesting Season of Sweet Orange

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1 Americn Journl of Experimentl Agriculture 4(11): , 2014 SCIENCEDOMAIN interntionl Gierellic Acid (GA3), n Influentil Growth Regultor for Physiologicl Disorder Control nd Protrcting the Hrvesting Seson of Sweet Ornge Rizwn Ullh1,2, Muhmmd Sjid2, Ghulm Ni3, Husin Ahmd2,4, Adur R2, Fheem Ahmed Khn5, Muhmmd Shh2, Hizr Suthin6, Shh Fhd7 nd Aziz Khn7 1 Key Lortory of Horticulturl Plnt Biology (MOE), Huzhong Agriculturl University, Wuhn , Chin. 2 Deprtment of Horticulture, University of Agriculture Peshwr, Pkistn. 3 Deprtment of Horticulture, University of Agriculture (Amir Muhmmd Khn Cmpus) Mrdn, Pkistn. 4 College of Horticulture, Northwest A nd F University, yngling, shnxi, Chin Moleculr Biotechnology, Lortory of Triticee crops HZAU Wuhn, Chin. 6 Ntionl Key Lortory of crop genetic improvement nd centre of plnt gene reserch, HZAU Wuhn , Chin. 7 Ntionl Key Lortory of Crop Genetic Improvement, MOA Key Lortory of Crop Ecophysiology nd Frming System in the Middle Reches of the Yngtze River, College of Plnt Science nd Technology, Huzhong Agriculturl University, Wuhn, Huei , Chin. Authors contriutions This work ws crried out in collortion etween ll uthors. All uthors red nd pproved the finl mnuscript. th Originl Reserch Article Received 11 April 2014 th Accepted 17 My 2014 th Pulished 19 June 2014 ABSTRACT Citrus prticulrly sweet ornge occupies n exlted position in fruit industry. Qulity sweet ornge production is ffected y vrious fctors including fruit physiologicl disorders nd hrvesting seson which contriute towrds consumer preference. This study ws designed to find out n economiclly fesile solution to these prolems. Three Corresponding uthor: Emil: rizwnhort@gmil.com;

2 different GA3 tretments (10, 20 nd 30ppm) were pplied s folir spry to three different sweet ornge cultivrs (Blood Red, Mosmi nd Succri) t full loom stge to investigte its influence on Physiologicl disorder in fruits s well s in shoots, fruit growth nd fruit mturity dely. The otined results reveled tht ll GA3 tretments specilly 30ppm significntly controlled fruit s well s shoots physiologicl disorders nd ws lso found efficient in cse of fruit mturity dely s compred to untreted trees. Finlly we were le to conclude tht; 30ppm GA3 should e pplied s folir spry to control fruit nd shoot physiologicl disorders nd to protrct the hrvesting seson of sweet ornge. Keywords: Folir spry; full loom; gierellic Acid; Mturity dely; physiologicl disorder; sweet ornge cultivrs. 1. INTRODUCTION Citrus is group of fruits occupies trenchnt position in the fruit industry ll over the world. In Pkistn, citrus ws grown on n re of thousnds hectres with n verge production of metric tonnes, which rnks it first mong fruits grown in country [1]. Likewise in United Sttes of Americ the on tree crop vlue ws estimted up to 1.35 illion USD during which generted roughly 76,000 full nd prt time jos [2]. The enefitcost rtio of sweet ornge is high s compred to lemon nd mndrin [3]. Sweet ornge is lso the most importnt fruit through nutritionl s well medicinl point of view. Severl extrcts from the peel of sweet ornge hve een reported which helps in curing of mny diseses, like Nringin extrcted from its peel hs therpeutic effect for Alzheimer type in humns [4], while the peel of citrus lso proved helpful in insulin stimultion [5]. Severl romtic compounds extrcted from sweet ornges hve een used in vrious food products for color nd tste development [6]. The demnd of sweet ornges mong consumers is incresing dy y dy, to fulfill this need, good qulity fruit production s well s high production per unit re is required. A huge mount of reserch work hs een conducted on these two spects, mny culturl prctices hve een recommended in this regrd like proper ppliction of nutrients nd irrigtion [7], mnging row to row nd plnt to plnt distnce, root stock selection [8] s well s the ppliction of vrious growth regultors [9,10]. To e more specific, in sweet ornges the nutritionl nd wter imlnce produce severe fruit disorders like fruit splitting, puffing, cresing nd wter mrks etc. [11], which decreses the fruit qulity nd ultimtely the consumer s preference. Gierellic cid hs een reported s n effective tretment in controlling unch fding disorder in dte plm[12], doule fruit nd fruit splitting disorder in pech [13], fruit cresing in Wshington Nvel sweet ornge [14] nd tipurn disorder in the leves of severl vegetles [15]. However in nother study [16] Nphthlene Acetic Acid (NAA) mentioned s n effective tretment for improvement in physiochemicl properties of dte plm. With reltion to rek seed 2+ dormncy GA inds to receptor nd C, ctivtes the protein clmodulin. The complex in turn inds to DNA producing n enzyme to stimulte growth in emryo [17]. The ioctive gierellins (GAs) re (GA1, GA3, GA4 nd GA7) mong which GA3 is the most iologiclly ctive form of gierellic cid [18]. In concern with fruit mturity dely, GA3 hs een reported s n influentil tretment in dte plm, protrcting its hrvesting seson [19,20]. With respect to these desirle nd importnt impcts of growth regultors, the present reserch study hs een designed with ojectives; (1) To control fruit physiologicl disorder nd (2) To prolong the hrvesting seson of sweet ornge through the folir ppliction of GA3, which re highly desirle in the fruit industry. 1356

3 2. MATERIALS AND METHODS 2.1 Experimentl Site, Design nd Plnt Mteril The experiment ws crried out t Agriculturl Reserch Institute (ARI) Trn, PeshwrPkistn, in yer The experimentl design used throughout the study ws; Rndomized Complete Block Design (RCBD) with two Fctors nd three replictions. Different gierellic cid concentrtions (0, 10, 20 nd 30ppm indicted s G0, G1, G2 nd G3) were considered s (Fctor A), while different sweet ornge cultivrs (Blood Red; Mosmi nd Succri indicted s C1, C2 nd C3) were tken s (Fctor B). Thirty six trees of three different sweet ornge cultivrs (mentioned ove) ech hving twelve trees were tgged. The tgging ws sed on the physicl nd micro environmentl similrity mong trees. Four different concentrtions of GA3 including control (mentioned ove) were spryed t full loom stge of sweet ornge cultivrs, nd their results were compred with control tretment. Ech tretment ws replicted three times. 2.2 Folir Appliction of Growth Regultor GA3 with the product nme (ProGi SG) produced nd merchndised y Sumitomo chemicls Austrli [21], contining the ctive ingredient (GA3) 400g/kg ws used. The chemicl s pplicle concentrtions were prepred, nd ph ws djusted ccording to the user s guide [21]. We crried out the spry procedure s prescried in the compny mnul [21] except the spry timing nd schedule. We pplied GA3 s single spry t full loom stge in the entire fruiting seson. In order to prepre 10, 20 nd 30ppm queous solutions, weight mesurements were determined pplying the following procedure [21]. ) 2.5g dissolved in 100 liters of wter = 10ppm (1) As per tree requirement ws found prior the ctul spry y sprying distilled wter to find the ctul volume of wter sufficient for ech tree. Therefore, weight clcultions were mde for 3 liters per tree ccording to the following procedure.. ) No. of grms dissolved in 3L of wter= = 0.075g (0.075g/ 3L=10ppm GA3) c) 0.075g 2= 0.15g (0.15g/3L= 20ppm GA3) d) g 3=0.225g (0.225g/3L=30ppm GA3) Solutions prepred sed on ove mentioned clcultions, were then pplied s folir spry on full loom stge of sweet ornge. 2.3 Mode of Action, Moleculr Structure, Formul nd Fetures of GA Mode of Action GA3 cts s plnt growth regultor, owing to its physiologicl nd morphologicl effects in extremely low concentrtions. Trnslocted nd predominntly influences the plnt prts ove the soil surfce [22]. 1357

4 2.3.2 Structurl nd moleculr formul GA3 (C19H22O6) Importnt fetures Gierellins re tetrcyclic diterpene. There re two ctegories ccording to the presence of cron numer either 19 or 20. Gierellins hving 19-crons, lost cron-20 nd consequently forms five-memer lctone ridge tht produces link etween cron 4 nd 10. In generl, the 19-cron form of gierellins is iologiclly more ctive s compred to 20-cron gierellins due to the presence of hydroxyl groups on cron 3 nd 13, hence referred s dihydroxyltion gierellins. GA3 is dihydroxylted gierellin [22,18]. 2.4 Oservtions Before the ppliction of GA3 s folir spry four rnches (one in ech direction) were selected. The selection ws mde on the sis of rnch size (hving pproximtely sme length nd dimeter) nd vigor. The following ttriutes were determined s: 2.5 Physiologicl Disorder Percentge in Shoots (PDS) Those shoots which hve the symptoms of nutrients deficiency like yellowing of old or new leves, mlformed or chlorotic leves etc. which minly involves environmentl fctors were crefully counted [22].The Physiologicl disorder percentge ws then determined through the following formul. %PDS = 100 (2) 2.6 Physiologicl Disorder Percentge in Fruits (PDF) Physiologicl disorder in fruits like fruit splitting, puffing, cresing, wter mrks nd peel pitting etc. ws found y counting the norml fruits s well s totl fruits per tree [22]. The percent physiologicl disorder in fruits ws clculted using following formul. %PDF = 100 (3) 1358

5 2.7 Dys to Fruit Mturity (DFM) The numer of dys ws counted from first dy of fruit set to the initition of fruit mturity indices (color, tste nd rom); their men ws tken nd presented grphiclly. 2.8 Fruit Growth (mm) Fruit growth ws determined y rndomly selected fruits on ech tree. Their dimeter ws regulrly mesured on weekly sis through Fruit Size Meter (Fig. 1), mde y (Crnston mchinery co. ok grove, Oregon, Austrli), their mens were tken nd then presented grphiclly to study the trend of fruit growth throughout the cell elongtion nd expnsion stge. Fig. 1. Fruit size meter used to determine the fruit dimeter regulrly on weekly sis 2.4 Sttisticl Anlysis The collected dt for ll prmeters ws nlyzed through (Sttistix8.1) sttisticl softwre, nd then lest significnt difference (LSD) ws computed for those prmeters which were sttisticlly significnt. The grphicl illustrtions were done through MS excel. 4. RESULTS AND DISCUSSION 3.1 Physiologicl Disorder in Shoots (PDS) Dt regrding PDS is grphiclly presented in Fig. 2. The dt pertining PDS shows tht there were significnt differences mong different tretments nd cultivrs, however the interctive effect ws non- significnt (Tle 1). According to the men vlues higher percentge (3.1) of PDS ws oserved in trees which were kept control while low intensity of PDS ws oserved in treted trees tht were (1.15, 1.18 nd 1.46) in 20, 10 nd 30ppm respectively. Among different Cultivrs, the mximum vlue (2.33%) ws oserved in Blood Red while the Succri (1.27%) nd Mosmi (1.48%) showed minimum counts of PDS. These differences mong different tretments nd cultivrs might e due the physiologicl response to the ppliction of growth regultor (GA3), however, there might lso e some 1359

6 % Physiologicl disorder in fruits genetic nd environmentl fctors responsile for these differences. In previous studies, certin vitmins were lso used s folir spry, dusting or drench ppliction to overcome nutrients deficiency y strengthening the plnts to sor more nutrients from soil nd those tretments cused severl desirle chnges within plnt ody, like stimultion of root formtion nd flower induction under non-inductive conditions s well s protecting plnts from severl ir pollutnts i.e. O3 nd SO2 [23]. Clcium inding proteins techniclly termed s Clcineurin B-like (CBL) proteins is up-regulted in the leurone lyer y GA. This lyer plys vitl role in the proper development of seed in rice nd rley [24]. Further CBL represent unique fmily of clcium sensors in plnt cell, sensing the clcium signls elucidted y vriety of iotic stresses [25]. Plnts growing in stress free environment hve more physiologiclly ctive gierellins which tend to increse the permeility of the 2+ cell memrne nd fcilitte the distriution of C to rpidly growing tissues, consequently mke it resistnt towrds tip urn disorder [15]. PDS Control 10ppm 20ppm 30ppm GA3 Concentrtions Blood Red Mosmi Succri Fig. 2. Physiologicl disorder percentge in shoots s ffected y different GA3 tretments in sweet ornge. (Grphicl illustrtion sed on grnd mens) 3.2 Physiologicl Disorder in Fruits (PDF) The sttisticl nlysis shows significnt differences mong different tretments nd cultivrs (Tle 1). Figs. 4 nd 3 represent the severity of fruit disorders nd its response to different levels of gierellic cid respectively. According to the dt presented, different GA3 tretments significntly influenced PDF in ll tested sweet ornge cultivrs. With reference to the dt given, higher percentge (2.76) of PDF ws oserved in untreted trees which ws significntly higher thn (0.96, 0.82 nd 0.76%) recorded in 30, 10 nd 20ppm respectively. The inter vrietl differences were lso significnt, with the highest vlue (1.76%) of PDF oserved in cv. Blood Red followed y cv. Succri(1.15%) nd cv. Mosmi (1.07%). While the interction of different tretments nd cultivrs were non-significnt. These differences mong different tretments nd cultivrs might e due to the influence of GA3 y preventing clcium deficiency directly or indirectly s stted erlier [25,26], which cn led to fruit splitting, however, there might e some other environmentl resons for fruit disorders, s in sweet ornges the nutritionl nd wter imlnce produce severe fruit 1360

7 disorders like fruit splitting, puffing, cresing nd wter mrks etc. [11]. The intensity of doule fruit nd fruit splitting disorder in pech ws successfully controlled through the ppliction of gierellic cid nd nitrogen to the trees with no wter stress [13]. GA3 nd NAA sprys in June nd July to Wshington Nvel Sweet ornge reduced the incidence of fruit cresing up to 25 nd 14% respectively [14] nd unch fding disorder in Dte plm [12]. % Physiologicl disorder in shoots PDF Control 10ppm 20ppm 30ppm GA3 concentrtions Blood Red Mosmi Succri Fig. 3. Physiologicl disorder percentge in fruits s ffected y different GA3 tretments in sweet ornge. (Grphicl illustrtion sed on grnd mens) Fig. 4. Intensity of fruit splitting disorder incresing with pssge of time nd fruit size 3.3 Dys to Fruit Mturity (DFM) The dt regrding DFM is presented in Fig. 5. There were highly significnt differences mong different tretments nd cultivrs regrding DFM s well s the interction of oth fctors ws lso significnt t (p=0.05) level of significnce (Tle 1). Accordingly, more numer of dys to fruit mturity (197.89) ws oserved in 30ppm treted trees closely followed y 10ppm (196.78) nd 20ppm (196.78) which hve non-significnt difference with ech other, while less numer of dys (187.22) ws tken y trees which were kept control. Likewise, mximum numer of dys to fruit mturity (195.75) ws recorded for cv. Blood Red nd Succri nd minimum numer of dys (192.50) ws tken y Mosmi sweet ornge. Almost ll GA3 tretments showed delying effect in terms of fruit mturity; it might e due to the influence of GA3 on chemicl compositions of sweet ornge fruits. It might lso e due 1361

8 to vrietl differences with respect to the numer of dys required to ttin fruit mturity y different cultivrs. GA3 reduces chlorophyll depletion nd crotenoid ccumultion, nd hence cuses color rek dely in fruit s peel [27]. Similrly GA3 ppliction results fruit ripening dely in Strwerry, which is highly perishle fruit crop [28]. Tle 1. PDS, PDF nd DFM s ffected y different GA3 tretments in sweet ornge cultivrs GA3 (Conc.) PDF PDS DFM c G G G G Significnce LSD (Tretments) Cultivrs C C C Significnce LSD (Cultivrs) Interction d G0 C e G0 C c d G0 C ef c G1 C cd de c G1 C f e G1 C f cde G2 C cde cde G2 C ef e G2 C def cd G3 C ef cde c G3 C cdef cde G3 C Significnce NS NS LSD ( Interction) significnce t α=0.05, NS=Non significnce. Vlues hving sme lphets hve no significnt differences mong ech other, while different letters indicte significnt differences. Sttisticl nlysis computed on replicted mens 3.4 Supplementry Informtion 3.5 Fruit Growth (mm) A continuous fruit growth recorded on weekly ses is presented in Fig. 6. Accordingly, cultivr Blood Red nd Succri showed very minor increse in fruit dimeter for treted trees s compred to untreted (control) trees while Mosmi remined unresponsive to GA3 pplictions. The grphicl presenttion of fruit growth showed non-significnt differences ecuse the rs representing different concentrtions followed lmost sme pttern for fruit growth. 1362

9 DFM Dys to fruit mturity ppm 10ppm 20ppm 30ppm GA3 concentrtions Blood Red Mosmi Succri Fig. 5. Grphicl illustrtion for DFM, s influenced y different GA3 ppliction s folir spry. (Grphicl illustrtion sed on grnd mens) Figure 6: Fruit growth (mm) determined right fter fruit set till fruit mturity indictes tht the fruit growth remins unresponsive towrds vrious concentrtions of GA3 pplied, which shows tht its ppliction up to this concentrtion level is sfe nd the fruits did not ffect negtively. Fig. 6. Response of fruit growth towrds different GA3 concentrtions pplied s folir spry in the period from fruit set till fruit mturity 1363

10 All sweet ornge cultivrs strted cell expnsion in erly June nd ttined mximum verge fruit dimeter (60mm with little fluctution) in erly Novemer. The min reson for following sme fruit growth pttern might e due to the fct tht ll cultivrs elong to the sme species, received sme concentrtions of GA3 nd lmost sme environmentl -1 conditions. The ppliction of (20 mg L ) GA3 delyed fruit mturity 5-8 dys only for the lte-mturing genotypes, ut did not ffect erly fruit mturing genotypes, while GA3 ppliction to Strwerry significntly incresed fruit weight nd size s compred to untreted plnts [29]. Gene ontogeny of plum fruit reveled tht GA1 nd GA4 re very importnt for fruit growth nd development. Further severl genes hve een elieved to e involved in GA signling prior fruit development [30]. 4. CONCLUSION The results reveled tht 30ppm GA3 ppliction is the est tretment to control fruit nd shoot physiologicl disorder long with prolonging the hrvesting seson of sweet ornge. All tested cultivrs responded positively towrds the folir ppliction of GA3 without ny mlformtion in their fruit growth. Therefore, it could e recommended tht 30 ppm GA3 should e pplied t full loom stge of sweet ornge in order to get these desirle effects under similr environmentl conditions. ACKNOWLEDGEMENTS The reserch ws fcilitted y Agriculturl Reserch Institute Trn Peshwr, Pkistn. I m personlly very much oliged to Dr. Muhmmd Sjid nd Dr. Ghulm Ni for providing me spce nd dvisory ssistnce. At the sme time, I m thnkful to ll of my collegues whose help enled me nd gve me strength to write this mnuscript. COMPETING INTERESTS Authors hve declred tht no competing interests exist. REFERENCES Agriculturl Sttistics of Pkistn, Government of Pkistn, Sttistics Division, Pk Bureu of Sttistics ;89:1-2. Florid Agriculturl Sttistics Services, Citrus sttistics. Florid citrus mutul. Ornge Street, Lkelnd USA; Ozkn B, Hndn A, Feyz K. Energy requirement nd economic nlysis of citrus production in Turkey. Energy conservtion nd mngement. 2004;45: Anil K, Smrit D, Atish P. Protective effect of Nringin, Citrus Flvonoid, ginst colchicine-induced cognitive dysfunction nd oxidtive dmge in Rts. J Med Food. 2010;13: Prmr HS, Kr A. Medicinl vlues of fruit peels from Citrus sinensis, Punicgrntum nd Mus prdisic with respect to lterntions in tissue peroxidtion nd serum concentrtion of glucose, insulin nd thyroid hormones. J Med Food. 2008;11: Kfks E, Ercisli S, Keml KN, Bydr K, Yilmz H. Chemicl composition of Blood Red vrieties from Turkey. A comprtive study. 2009;5: Alv AK, Prmsivm S, Grhm WD, Wheton A. Best nitrogen nd irrigtion mngement prctices for citrus in sndy soil. Wter Air Soil poll. 2003;143:

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12 28. Oh SI, Prk J, Yoon S, Kim Y, Prk, S, Ryu M, Kim KN. The Aridopsis clcium sensor clcineurin B-like 3 inhiits the 5 -methylthiodenosine nucleosidse in clcium-dependent mnner. Plnt physiology. 2008;148(4): Oertli JJ. Exogenous ppliction of vitmins s regultors of growth nd development of plnts, review. J Plnt Nutr Soil Sc. 2007;150: Alos E, Cercos M, Rodrigo MJ, Zcris L, Tlon M. Regultion of color rek in citrus fruits, chnges in pigment profiling nd gene expression induced y gierellins nd nitrte, two ripening retrdnts. J Agr Food Chem. 2006;54: Ullh et l.; This is n Open Access rticle distriuted under the terms of the Cretive Commons Attriution License ( which permits unrestricted use, distriution, nd reproduction in ny medium, provided the originl work is properly cited. Peer-review history: The peer review history for this pper cn e ccessed here: