Ksetsrt J. (Nt. Si.) 47 : 818-827 (2013) Physiologil Qulity nd Desition Sensitivity of Ruer (Heve rsiliensis) Seeds during Fruit Mturtion Wiphrt Dung-it, Vihi Wongvrodom*, Wullop Sntiprh nd Syn Sdoodee ABSTRACT The physiologil qulity nd desition of ruer seeds were investigted during development. Fruits of ruer lone RRIM 600 t different stges of development were olleted from plnttion in Nkhon Sri Thmmrt provine, southern Thilnd, during July August 2012. Seeds of deep green fruit, yellowish-green fruit, rown fruit nd from the nturlly shedding stge were tested for their weight, moisture ontent, germintion, men germintion time, seedling shoot height, seedling shoot dry weight, eletril ondutivity nd desition tolerne during dry storge. Ruer seeds with high germintion rnging from 86.67 to 95.00% were otined from the yellowish-green fruit, rown fruit nd nturlly shedding stges. However, the seeds rehed physiologil mturity t the rown fruit stge with vlues for seed dry weight, moisture ontent nd germintion of 2.93 g per seed, 34.54% nd 95.00%, respetively. At the shedding stge, the seeds hd moisture ontent nd high germintion of 22.17% nd 91.66%, respetively. The ritil moisture ontent of the seeds ws 15% nd t this level, they were very short lived (3 7 d in dry onditions). The seeds with moisture ontent of out 15% nd from 11 to 12% hd germintion of 58.33 63.34% nd 1.67 8.34%, respetively. Therefore, the erly olletion of the shed seed is reommended to ensure high qulity seed is otined. Suh informtion my e helpful for improving the seed olletion or trnsport proedures nd ensuring high seed performne in the seeded for suessful rootstok prodution. Keywords: ruer (Heve rsiliensis), seed qulity, relitrnt seed, mturity, seed desition INTRODUCTION Ruer (Heve rsiliensis) is n importnt eonomi ommodity. Most ruer plnttions re plnted with udded seedlings or udded ruer stump either in polyethylene gs or s re-rooted stumps otined y grfting sion of high yielding lone onto seedling rootstok (Ruer Reserh Institute of Thilnd, 2013). The prodution of udded stumps normlly requires lot of seed for rootstok prodution. Ruer Reserh Institute of Thilnd (2013) reported tht the re of ruer plnttion nd the replnted res of Thilnd in 2010 were out 2,931,201 nd 34,228 h, respetively whih required udding of more thn 17,114,000 seedlings for the replnting opertion. Therefore, high quntity of ruer seed is needed for rootstok prodution eh yer. The suess of rootstok prodution with ruer trees lrgely depends on the vilility of good qulity seed from whih to produe good qulity splings tht re uniform, Deprtment of Plnt Siene, Fulty of Nturl Resoures, Prine of Songkl University, Ht Yi, Songkhl 90112, Thilnd. * Corresponding uthor, e-mil: vihi.w@psu..th Reeived dte : 03/06/13 Aepted dte : 12/09/13
Ksetsrt J. (Nt. Si.) 47(6) 819 helthy nd vigorous, whih in turn influenes the udding proess nd lso the rootstok s influene on the performne of the sion fter the udding (Dud et l., 2012). However, it is often found tht ruer seed soured from nturl shedding hs low qulity, whih might e due to the rpid loss of viility fter shedding under nturl onditions euse of the relitrnt ehvior of the seeds y the desition sensitivity (Chin nd Roerts, 1980). The seed mturity nd the moisture ontent re ruil in determining seed viility (Ln et l., 2007). Kushik (2003) reported tht the vigor of Jtroph urs seeds otined from green fruit ws lower thn tht from yellow or rownish-lk fruits nd the est physiologil qulity seeds were otined from yellow fruit. During desition, seeds of Hope prvifl or nd H. pomg redued germintion elow moisture ontent of 26% nd 28%, respetively (Rjeeswri nd Kveripp, 2000). Seed of Mngifer persiiformis lost 50% viility t moisture ontent of 21.50% nd seed with moisture ontent of 18.3% hd lmost no germintion (Tng et l., 2008). However, there is lk of suffiient knowledge of ruer seed mturity nd desition fter shedding for qulity ontrol nd mngement to ensure the use of high qulity seed for ruer root stok prodution. The ojetives of this investigtion were to study ruer seed qulity during fruit mturtion nd the hnge in seed qulity during the desition of the ruer seed. MATERIALS AND METHODS Colletion of fruits Fruits of ruer lone RRIM 600 t different stges of development were olleted from plnttion in Nkhon Sri Thmmrt provine, southern Thilnd, during July August 2012. Seeds from four developmentl stges: 1) immture fruit (deep green fruit), 2) erly mture fruit (yellowish-green fruit), 3) mture fruit efore shedding (rown fruit with reking strip on the perirp) nd 4) fruit-shedding stge (Figure 1) were tested for qulity in four replites. Moisture ontent nd fresh nd dry weight The moisture ontent ws determined for whole seed, the emryo, endosperm nd test. Six seeds nd 10 piees of eh struture per replition were weighed nd dried t 105 o C for 24 hr. Dry seed nd its struture were weighed, nd the moisture ontent ws lulted on perentge of wet weight sis. The fresh weights of whole seed nd the seed prts were lso lulted in grms per seed. Germintion Fifteen seeds per replition were germinted in moist snd in plsti sket nd pled in plsti lthe house. First nd finl ounts were done t 7 nd 21 d fter germintion (DAG), respetively (Chin nd Roerts, 1980). Norml seedlings were verged s the germintion perentge. Men germintion time The seeds were germinted in germintion test. Bsed on the ruer seed germintion ehvior, norml seedlings were ounted t 7, 14, nd 21 DAG nd the men germintion time (GMT) ws lulted using the formul in Eqution MGT = Σnd / Σn s desried y Ellis nd Roerts (1981): Where n is the numer of seeds whih germinte on dy D nd D is the numer of dys ounted from the eginning of the test. Seedling growth Five norml seedlings per replition from the germintion test were mesured for shoot length. The seedling shoots were ut ove the snd-medium surfe nd the shoots from eh replition were seprtely dried t 80 C for 24 hr. Dry seedling shoots were weighed. Eletril ondutivity Five seeds per replition were weighed
820 Ksetsrt J. (Nt. Si.) 47(6) Figure 1 Ruer fruit nd seed t different stges of development: () Deep green fruit; () Seed from deep green fruit; () Yellowish-green fruit; (d) Seed from yellowish-green fruit; (e) Brown fruit; (f) Seed from rown fruit; (g) fruit; (h) Seed from nturlly shedding fruit.
Ksetsrt J. (Nt. Si.) 47(6) 821 nd soked in 75 ml of deionised wter t 25 C for 24 hr. The eletril ondutivity of the steep wter ws mesured using ondutivity meter. Desition tolerne nd storility Seeds from the different smpled fruit developmentl stges were stored in plsti skets t room temperture for 0, 3 nd 7 d. Then, the stored seeds were tested for their moisture ontent, germintion, men germintion time, seedling shoot dry weight nd eletril ondutivity using the proedures desried erlier. Sttistil nlysis The experiments were rrnged in ompletely rndomized design nd their mens were ompred using Dunn s multiple rnge test. RESULTS Qulity of ruer seed t different developmentl stges The fresh nd dry weights of ruer seed nd its prts orresponded to their development or mturity. The hnges in the fresh weight nd dry weight of ruer seed nd its strutures throughout development re shown in Tle 1. The fresh weight of the whole seed, emryo, endosperm nd test grdully deresed from the green fruit to the nturlly shedding stge with vlues of 4.94 3.47, 0.31 0.27, 2.39 1.73 nd 1.63 1.37 g per seed, respetively. The dry weights of the whole seed, emryo, endosperm nd test exhiited similr hnges with grdul inrese during the erly stge of development, rehing mximum t the rown fruit stge, followed y slight derese. From the green fruit to rown fruit stge, the seed dry weight inresed from 2.34 g per seed to mximum of 2.93 g per seed nd then delined to 2.69 g per seed y the nturl shedding stge. The hnges in the emryo, endosperm nd test dry weights orresponded with tht reported for the whole seed. The dry weight of the emryo, endosperm nd test were mximl during the rown fruit stge with vlues of 0.22, 1.41 nd 1.30 g per seed, respetively. The moisture ontent of the seed nd the emryo, endosperm nd test, grdully delined from the deep green fruit to the nturlly shedding stge. The seed moisture ontent deresed with mturtion from 52.52% to 22.17% whih ws sttistilly signifint (P < 0.01). The hnge in the moisture ontent of the emryo, endosperm nd test during development orresponded with tht in the whole seed. At the nturlly shedding stge, the moisture ontent of the emryo, endosperm nd test were miniml with vlues of 23.82, 23.78 nd 12.83%, respetively (Tle 2). The germintion nd vigor of ruer seed depended on the stge of development. Seed from deep green fruits hd the miniml germintion Tle 1 Fresh nd dry weights of ruer seed nd its prts in different fruit developmentl stges. Fruit developmentl stge Deep green fruit Yellowish-green fruit Brown fruit Nturlly Shedding Fresh weight (g per seed) Whole Emryo Endosperm Test seed 4.94 4.61 4.48 3.47 0.31 0.32 0.37 0.27 2.39 2.50 2.35 1.73 1.63 1.55 1.54 1.37 Whole seed 2.34 2.68 2.93 2.69 Dry weight (g per seed) Emryo Endosperm Test 0.15 0.17 0.22 0.21 0.88 d 1.19 1.41 1.32 F-test * * ** * ** ** ** * CV (%) 6.14 6.81 5.06 3.72 3.72 8.41 4.84 3.73 Mens in eh olumn with the sme lowerse letter re not signifintly different y Dunn s multiple rnge test. *,**Signifint t P < 0.05 nd P < 0.01, respetively; CV = Coeffiient of vrition. 1.22 1.27 1.30 1.20
822 Ksetsrt J. (Nt. Si.) 47(6) Tle 2 Moisture ontent of ruer seed nd its prts in different fruit developmentl stges. Fruit developmentl stge Moisture ontent (%) Whole seed Emryo Endosperm Test Deep green fruit Yellowish-green fruit Brown fruit 52.52 41.70 34.54 22.17 d 50.52 48.37 41.08 23.82 63.22 52.59 40.03 23.78 d 25.03 17.74 15.38 12.83 d F-test ** ** ** ** CV (%) 7.00 7.57 5.33 3.46 Mens in eh olumn with the sme lowerse letter re not signifintly different y Dunn s multiple rnge test. ** Signifint t P < 0.01; CV = Coeffiient of vrition. of 16.67%. The germintion did not hnge signifintly fter the yellow green fruit stge up to the nturlly shedding stge with vlues in the rnge 86.67 95 91.66% (Tle 3). The development of seed vigor in terms of the men germintion time, seedling shoot height, seedling shoot dry weight nd eletril ondutivity lso showed similr trends to tht of germintion. The seed vigor inresed s the fruit developmentl stge inresed nd rehed its mximum in the rown fruit stge, followed y slight derese in the nturlly shedding stge. The men seed germintion time ws high (21.00 d) prior to the yellowish-green fruit stge nd then deresed to 14.35 d t the rown fruit stge, followed y signifint (P < 0.05) inrese (18.21 d) for nturl shedding seed. Seed from deep green fruits hd seedling shoot height of 9.33 m whih then inresed to 37.95 35.35 m in the lter fruit developmentl stges. Brown fruit seed produed the mximum seedling shoot dry weight of 0.62 g per seed, while seed from deep green fruits, yellowish-green fruits nd the nturlly shedding stge ll produed lower seedling shoot dry weights of 0.07, 0.51 nd 0.46 g per seed, respetively. The eletril ondutivity of seed delined with the dvnement of mturity from 2.14 μs.m -1.g -1 t the deep green fruit stge to 1.09 μs.m -1.g -1 t the rown fruit stge. The eletril ondutivity signifintly (P < 0.01) inresed t the nturlly shedding stge (1.39 μs.m -1.g -1 ). Tle 3 Germintion, men germintion time, seedling shoot height, seedling shoot dry weight nd eletril ondutivity of ruer seed from different fruit developmentl stges. Fruit Men Seedling Seedling shoot Eletril Germintion developmentl germintion shoot height dry weight (g ondutivity (%) stge time (d) (m) per seedling) (μs.m -1.g -1 ) Deep green fruit Yellowish-green fruit Brown fruit 16.67 86.67 95.00 91.66 21.00 17.18 14.35 18.21 9.33 37.95 36.30 35.35 0.07 0.51 0.62 0.46 2.14 1.45 1.09 1.39 F-test ** * ** ** ** CV (%) 17.30 8.79 10.47 11.39 7.28 Mens in eh olumn with the sme lowerse letter re not signifintly different y Dunn s multiple rnge test. *,**Signifint t P < 0.05 nd P < 0.01, respetively; CV = Coeffiient of vrition.
Ksetsrt J. (Nt. Si.) 47(6) 823 Chnges of qulity during desition of ruer seed of different developmentl stges The moisture ontent of seed delined with the mturtion nd desition period. Seeds otined from the deep green fruit, yellowishgreen fruit, rown fruit nd the nturlly shedding stges hd moisture ontents of 52.52, 41.70, 34.54 nd 22.17%, respetively (Figure 2). At 3 d of desition, the moisture ontent of seed from deep green fruits ws high (40.60%), while seeds from yellowish-green fruits, rown fruits nd the nturlly shedding stge hd moisture ontents of 26.37, 21.95 nd 14.24%, respetively. Seeds of deep green fruits nd ll three stges of development fter 7 d of desition dried to 30.94% nd 15.30 10.74% moisture ontent, respetively. The desition sensitivity of ruer seed depended on the development stge nd dehydrtion times. Freshly hrvested seed of deep green fruits hd the lowest germintion of 16.67% with seeds from the lter stges of fruit development ll produing the sme germintion in the rnge 86.67 95.00% (Figure 3). After 3 d Moisture ontent (%) 60 50 40 30 20 10 d d Deep green Yellowish green Brown 0 0 3 7 Desition period (dys) Figure 2 Moisture ontent of ruer seeds from different fruit developmentl stges t different periods of desition. Fruit developmentl stges in the sme desition period with the sme lowerse letter re not signifintly different (P < 0.05). Germintion (%) 100 90 80 70 60 50 40 30 20 10 0 0 3 7 Deep green Yellowish green Brown Desition period (dys) Figure 3 Germintion of ruer seeds from different fruit developmentl stges t different periods of desition. Fruit developmentl stges in the sme desition period with the sme lowerse letter re not signifintly different (P < 0.01).
824 Ksetsrt J. (Nt. Si.) 47(6) of desition, the germintion of seeds of deep green fruits nd the nturlly shedding stge ws muh lower thn for seeds from the yellowishgreen nd rown fruit stges. At 7 d of desition, most seeds susequently eme more sensitive to desition with germintion lower thn 10%. However, the seeds otined from yellowish-green fruits still hd higher germintion of 63.34%. The men germintion time nd seedling shoot dry weight orresponded to the germintion results (Figure 4 nd 5). Seeds of yellowish-green fruit exhiited greter desition tolerne thn those of the other stges t 7 d fter desition. During desition, the eletril ondutivity inresed in every development stge, ut the eletril ondutivity of seed from deep 25 Men germintion time (d) 20 15 10 5 Deep green Yellowish green Brown 0 0 3 7 Desition period (d) Figure 4 Men germintion time of ruer seeds from different developmentl stges t different periods of desition. Fruit developmentl stges in the sme desition period with the sme lowerse letter re not signifintly different (P < 0.05). Seedling shoot dry weight (g per seedling) 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 0 3 7 Deep green Yellowish green Brown Desition period (d) Figure 5 Seedling shoot dry weight of ruer seeds from different fruit developmentl stges t different periods of desition. Fruit developmentl stges in the sme desition period with the sme lowerse letter re not signifintly different (P < 0.01 nd 0.05 for 0 nd 3 d of desition, respetively).
Ksetsrt J. (Nt. Si.) 47(6) 825 green fruits inresed more rpidly thn those of yellowish-green fruits, rown fruits nd the nturlly shedding stge (Figure 6). DISCUSSION Physiologil mturity is the stge of development when the seeds reh their mximum dry weight nd mrks the end of seed-filling time (Ln et l., 2007). This point n e defined in mny speies using the numer of dys fter nthesis or flowering suh s for Hope hinnensis (Ln et l., 2007) nd Artorpus heterophyllus (Chudhury nd Mlik, 2004). For exmple, the physiologil mturity of Hope hinnensis seed ppers to e t 157 d fter nthesis, when the seed hs ttined its mximum dry weight of 0.43 g. However, there re exeptions to this; the physiologil mturity stge of Jtroph urs ould e determined y the visul spet of fruit olor (Drnski Jr. et l., 2010; Silv et l., 2012). Physi nut seeds with high physiologil qulity re otined from yellowish-rown fruits whih gve the highest germintion nd vigor in terms of the first ount of germintion, elerted ging nd eletril ondutivity (Silv et l., 2012). As shown in Tle 1, ruer seed nd its emryo, endosperm nd test, reh their mximum dry weight vlues of 2.93, 0.22, 1.41 nd 1.30 g per seed, respetively, t the rown fruit stge. At this stge, the seeds hd the highest physiologil qulity in terms of germintion (95.00%), men germintion time (14.35 d), seedling shoot height (36.30 m), seedling shoot dry weight (0.62 g per seedling) nd eletril ondutivity (1.09 μs.m -1.g -1 ) s shown in Tle 3. Seed of nturlly shedding fruits hd similr germintion nd vigor s seeds of rown fruit lthough there ws slight derese in the seedling shoot dry weight nd eletril ondutivity whih indited the deteriortion of memrne integrity. Seed of yellowish-green fruits produed the sme level of germintion s tht of rown fruits; however, lower seed vigor ws found. The seeds from deep green fruits hd low germintion pity euse of the low food umultion (dry weight; 20.4 g per seed) s shown in Tle 1 nd there ws inomplete memrne orgniztion with the highest eletril ondutivity of 2.14 μs.m -1.g -1 (Tle 3). Silv et l. (2012) found tht physi nut seed otined Eletril ondutivity (µs.m -1 g -1 ) 4 3.5 3 2.5 2 1.5 1 0.5 Deep green Yellowish green Brown 0 0 3 7 Desition period (d) Figure 6 Eletril ondutivity of ruer seeds from different fruit developmentl stges t different periods of desition. Fruit developmentl stges in the sme desition period with the sme lowerse letter re not signifintly different (P < 0.01, 0.05 nd 0.01 for 0, 3 nd 7 d of desition, respetively).
826 Ksetsrt J. (Nt. Si.) 47(6) from green fruits hd the lowest physiologil qulity with the highest eletril ondutivity of 113.95 μs.m -1.g -1. The results of the urrent study indited tht during seed development nd mturtion, there were hnges in the fresh weight, dry weight, moisture ontent, germintion nd vigor s desried y Bewley nd Blk (1994). The ruer seed hieved physiologil mturity t the rown fruit stge with the highest seed dry weight nd germintion potentil. The ruer seed lost viility rpidly within few dys under dry onditions (Figures 3, 4, 5 nd 6). The dt indited tht the rte of ruer seed deteriortion depended on the mturtion stge nd the seed moisture ontent fter desition. The seeds from the yellowishgreen, rown nd nturlly shedding stges with moisture ontents in the rnge 22.17 41.70% hd high germintion of 86.67 95.00% t 0 3 d of desition. The seeds with moisture ontent of out 15% nd 11% hd germintion of 58.33 63.34% nd 1.67 8.34%, respetively, fter 3 7 d of desition. The results orresponded with those of other reserhers nd other desition-sensitive speies whih exhiit loss of viility elow ritil moisture ontent of: 15 20% in ruer (Chin et l., 1981); 24% in mngosteen (Normh et l., 1997); nd 40, 25 nd 33% in mngo, longn nd lyhee, respetively, (Fu et l., 1990). However, during the desition period, seed from the deep green fruits whih ws immture, hd low germintion (16.67 6.67%) despite high moisture ontent in the rnge 31.03 52.59%. The results indited tht the mture seed of ny fruit stge (yellowish-green, rown nd from nturl shedding) exhiited no desition tolerne when the moisture ontent delined to 15% or elow. In most seed, there ws notiele loss in viility or germintion performne. However, seed from the yellowish-green fruit with moisture ontent of 41.70% fter hrvesting still hd moisture ontent of 15.30% with germintion of 63.34% t 7 d fter desition while those of the other mture fruit stges hd moisture ontents of out 11% with germintion of only 1.67 8.34%. Ln et l. (2007) reported tht Hope hinnensis seed with n emryoni xis 150 d fter nthesis exhiited the highest desition tolerne while the seed rehed its physiologil mturity t 157 d fter nthesis. The results otined from the olletion of nturlly shedding seed suggested tht it should e olleted s quikly s possile to ensure high seed qulity. Any dely in the olletion would result in inresed levels of mortlity nd redued qulity. There would lso e ost ssoited with plnting mteril, trnsporttion, seeded mngement s well s possile dverse impt on seedling performne nd ultivtion prtie in rootstok prodution. For the suessful development of reeding progrm nd future ruer rootstok seed grden where there is ontrol over the nopy or height of the ruer trees, the optiml stge of fruit development should determine the timing of seed olletion. CONCLUSION Ruer seeds with high physiologil qulity, germintion nd vigor were otined from the yellowish-green stge, from the rown fruit stge nd from the nturlly shedding stge. The seed rehed physiologil mturity t the rown fruit stge with seed dry weight, moisture ontent nd germintion of 2.93 g per seed, 34.549% nd 95.00%, respetively. At the shedding stge, the seed hd moisture ontent nd germintion of 22.17% nd 91.66%, respetively. However, the seed were very short-lived nd hd deteriorted within 3 7 d of dry onditions. The seeds with moisture ontent of out 15% nd 11 12% hd germintion of 58.33 63.34 nd 1.67 8.34%, respetively. Therefore, it is suggested tht newly shed seed needs to e olleted s soon s possile to ensure high qulity seed is otined. ACKNOWLEDGEMENTS This work ws supported y higher
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