Department of Horticulture, PMAS Arid Agriculture University, Rawalpindi, PakistanDepartment of Soil Science, PMAS Arid Agriculture University, Rawalpindi, Pakistan
r t i c l e i n f o
rticle history:eceived 6 January 2013eceived in revised form 15 August 2013ccepted 12 September 2013
eywords:ntioxidantsatalaseembrane leakage
a b s t r a c t
Zinc being an activator of certain enzymes, regulates antioxidant activity; therefore, it could enhancethe shelf life of cut flowers. This study on zinc (Zn) nutrition of gladiolus was conducted for two years(2010–2011) in the greenhouse. Graded levels of zinc, viz., 0, 2, 4, 6, 8 and 10 mg Zn kg−1 were applied insoil media. Results in both the years revealed significant positive response to zinc application on growthand vase life attributes of gladiolus. Zinc at 6 mg kg−1rendered the highest impact for increasing theleaf area, spike length, flower size, fresh and dry biomass weight. Less number of days to flowering andhigher count of florets per spike was recorded with 8 mg Zn kg−1. Chlorophyll and protein contents werehighest at 6 mg Zn kg−1; whereas, Zn contents were highest with 10 mg Zn kg−1. Vase quality parameters
−1
uperoxide dismutasease life
like percent florets opened, vase life and fresh weight change were greater with 8 mg Zn kg , and theleast membrane leakage was also ensured at this rate. Antioxidant enzymes, viz., SOD, CAT, POD andfree radical scavenging activities in cut flowers remained at the highest with 6 mg Zn kg−1. This studyconcludes that Zn applied at 6–8 mg kg−1 imparts greater beneficial effects on growth, production, vaselife quality, and antioxidative activities in gladiolus cut flower, and further higher application rates rendernon-significant improvement.
. Introduction
Role of zinc (Zn) is well established in the formation of trypto-han, a precursor to indole acetic acid (IAA) and RNAase (Rashid,005). It enhances the plant growth (Sarwar et al., 2012), flowerroduction and quality as well. It is an activator of certain enzymes
ike alcohol dehydrogenase, superoxide dismutase (SOD) and RNAolymerase (Rashid, 2005). Compared to other micronutrients,inc concentration in biological systems is higher, particularly iniomembranes (Cakmak, 2000). Contribution of Zn in regulatinghe antioxidative activities, viz., SOD (Pandey et al., 2002), CAT andOD (Aravind and Prasad, 2003) has been well documented. There-ore, it could potentially enhance the shelf life by scavenging the
eactive oxygen species (ROS) to cope with oxidative damage andetaining the membrane integrity.
∗ Corresponding author at: Department of Soil Science, Pir Mehr Ali Shah Aridgriculture University, Rawalpindi 46300, Pakistan. Tel.: +92 51 9290692;
ax: +92 51 9290692.∗∗ Corresponding author at: Department of Horticulture, Pir Mehr Ali Shah Aridgriculture University, Rawalpindi 46300, Pakistan. Tel.: +92 51 9290692;
Gladiolus (Gladiolus hortulanus L.) ranks second in productionand consumers’ preference among the cut flowers. Gladiolus cutflowers are one on the most famous and well-liked in the world fortheir majestic spikes, which contain attractive, elegant and delicateflorets. Its florets open in a sequence over a longer duration; there-fore, it has good keeping quality and is an excellent cut flower. It isfrequently used in landscape, bedding, bouquets, flower arrange-ment etc. (Arora, 2007). Commercial production of gladiolus cangenerate not only good income but can also fetch foreign exchangethrough their export.
Market value of cut flowers depends upon many factors as spikelength, number of florets, quality of intact flower, flower freshness,and vase life. Therefore, more focus is given on the flower qual-ity along with its production. Micronutrient deficiency is one ofthe major preharvest constraints for premium quality production;especially zinc deficiency is the global issue (Pandey et al., 2002).
Postharvest longevity of cut flowers is a key factor that con-tributes the esthetic and marketable value of the crop (Mansouri,2012). Petals are the floral organs that determine primarily thecommercially acceptable esthetic value of flowers. Therefore, muchattention is required to improve all the biochemical and physi-
ological processes that take place during petal development andsenescence (Sood et al., 2006). These processes are characterized byseveral phases, viz., cellular division, differentiation, expansion andultimate petal cell death or senescence. Senescence of cut flowers
riggers right from their harvest due to various factors (Shahri andahir, 2011). Oxidative stress and membrane leakage during vaseife are the major factors leading to the early senescence in ethylenensensitive cut flowers including gladiolus (Ezhilmathi et al., 2007).inc nutrition could play major role to cope with oxidative stressy enhancing antioxidative activity and improving the membranetability (Cakmak, 2000). These facts suggest that optimum levelf zinc could be beneficial for growth and postharvest quality, ifpplied preharvest to the gladiolus crop. Therefore, present studyas undertaken to investigate the mechanism by which preharvest
pplied zinc could influence the quality production, shelf life andntioxidative capacity of gladiolus cut flowers.
. Materials and methods
Experiment was carried out with Gladiolus hortulanus cv. “Whiterosperity” raised under greenhouse conditions. Various levels ofn, viz., 0, 2, 4, 6, 8 and 10 mg kg−1 were applied as zinc sul-hate in the pots containing 10 kg soil media. Basal dose of N-P-Kas applied uniformly at 60–45–30 mg kg−1, respectively in all
he treatment pots. Soil media used had sandy loam texture, withH (1:5), 7.4; ECe, 7.4 dS m−1; organic matter, 0.37%; total N,.021%; available P, 8.6 mg kg−1; extractable K, 120 mg kg−1; and Zn.85 mg kg−1 (AB-DPTA). For postharvest investigations, gladioluspikes were harvested at 2–3 opened florets stage and re-cut to theniform size of 90 cm (±5) under water. Flower spikes were placed
n glass jars containing distilled water at 25 ± 2 ◦C with 14 h illumi-ation period. Experiment was laid out in completely randomizedesign (CRD) with four replications. There were 36 cut flower spikessed for the postharvest study. Twenty four cut spikes (six for eacheplicate) were used for biochemical analysis (SOD, POD, CAT andree radicals scavenging activity) and membrane leakage. Twelvepikes (three of each replicate) were thus left to determine the vaseife. Data were recorded on the following parameters:
.1. Plant growth and floral parameters
Data on leaf area, spike length, number days to flowering, num-er of florets per spike, flower size and fresh weight of flower wereecorded at harvest stage.
.2. Bio-chemical attributes
Chlorophyll contents (by SPAD 502 Konica Minolta, Japan), Znoncentration (on atomic absorption spectrophotometer), and pro-ein contents (Bradford, 1976) in plant leaves were determined.
.3. Vase life parameters
Data on % age of florets opened, vase life, and percent fresheight change were recorded during shelf life. There were 12 cut
pikes (3 in each replicate) for the vase life parameters.
.4. Membrane leakage
Membrane leakage was measured through the methodescribed by Singh et al. (2008) with a slight modification. Fiveower petal discs having 10 mm diameter from each treatment
ere put together into test tube containing 10 mL distilled water.
nitial membrane leakage was determined by using a conductivityeter following incubation of the test tubes at 25 ◦C for 180 min.
hen solution was boiled in a water bath for 10 min to liberate all
urae 164 (2013) 124–129 125
the electrolytes before the final conductivity was measured. Mem-brane leakage was calculated as below:
electrolyte leakage (%) = C1
C2× 100
where, C1 is electrical conductivity of petals after 180 min roomincubation and C2 is the final electrical conductivity of the solution.
2.5. Preparation of cell free enzyme extract
One gram sample of frozen flowers (in liquid nitrogen) wastaken from each replicate and was grinded in pre-cold mortar andpestle. The tissues were suspended in 5 mL of 0.1 M KPO4 buffer(pH 7.8) containing 0.5% Triton and 0.2 g of PVPP. The mixture wascentrifuged at 27,000 × g for 30 min at 4 ◦C (Abbasi et al., 1998).
2.6. Superoxide dismutase assay
Superoxide dismutase (SOD) activity was determined by follow-ing the method as described by Dhindsa et al. (1981) with somemodifications. The SOD activity was estimated by measuring theinhibition of photochemical reduction of nitro blue tetrazolium(NBT). Two sets of five cuvettes (3 mL) each containing 0, 100, 200,300 or 400 mL of enzyme extract were added with 50 mM KPO4buffer (pH 7.8) and reaction mixture. One set of 5 reaction cuvetteskept in the dark served as control (blank) while the other set wasplaced under fluorescent lamps for 10 min. Absorbance of solutionwas read at 560 nm wavelength with spectrophotometer (Optima®
3000 plus). One unit of SOD is defined as the amount of enzyme thatcan inhibit the activity of NBT photo reduction by 50%. The enzymeunit was expressed as units g−1 protein.
2.7. Peroxidase assay
Peroxidase (POD) activity was assayed according to the methodmentioned by Hassan et al. (2007) with slight modifications.Assay mixture consisted of 1 mM H2O2, 0.1 mM guaiacol in 15 mMNaKPO4 buffer (pH 6.0) and 200 �L crude enzyme extract. The PODactivity was recorded at 470 nm as a change in the optical density(OD) over a 3 min period and expressed as units g−1 protein.
2.8. Catalase assay
Catalase (CAT) activity was assayed according to the methoddescribed by Abbasi et al. (1998). Reaction was carried out by usingtwo buffer solutions, one containing 50 mM KPO4 buffer and otherconsisting of 12.5 mM H2O2 in 50 mM KPO4 (pH 7.0) Reaction wasstarted by adding 300 �L enzyme to each buffer in 3 mL cuvettes,and OD was recorded at 240 nm. One unit of catalase activity wasexpressed as enzyme units g−1 protein.
2.9. Protein determination
Total protein assay of gladiolus was undertaken by Bradford(1976) method, using bovine serum albumin as the standard.This method is based on the phenomena of proteins to bind theCoomassive brilliant blue G-250 (dye). For protein assay, 100 �Lsupernatant was added in 5 mL protein reagent. Optical densitywas recorded at 595 nm against protein reagent (blank) 0.1 mLbuffer + 5 mL protein reagent. The protein unit was expressed asmg protein g−1 fresh weight.
2.10. Free radical scavenging activity
Free radical scavenging activity (FRSA) was measured bythe modified version of Brand-Williams et al. (1995) method.
1 rticulturae 164 (2013) 124–129
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with each other at 8th and 10th day of shelf life. Strangely, 10 mgZn kg−1 gave the lowest SOD activity among all the zinc levels. ThePOD activity at 10th day of shelf life was statistically similar to thatwith 2 and 6 mg Zn kg−1 both being at the top. Application of 4
20
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26 T. Saeed et al. / Scientia Ho
cavenging activity of free radicals was determined by scavenginghe free radical 2,2-diphenyl-l-picrylhydrazyl (DPPH) prepared in
ethanol solution. Frozen tissues of flowers (1 g) were grinded andxtracted in 5 mL methanol. Absorbance was recorded at 515 nm at
and 30 min. Radical scavenging activity was calculated as percentf inhibition of DPPH radical by using the following formula:
nhibition (%) = B − A
AB× 100
here, B is the absorption of blank sample (0 min), and A is thebsorption of extract solution (30 min).
.11. Statistical analysis
Experiment was laid out according to completely randomizedesign (CRD) with four replications. Data on plant growth, floralnd biochemical attributes as influenced by Zn application levelsere subjected to analysis of variance. Treatment means of theseata were separated by Duncan’s multiple range test as describedy Steel et al. (1997).
. Results
.1. Plant growth parameters
All the growth characteristics were significantly affected by zincpplication (Table 1) except number of leaves per plant and spikeiameter (data not shown). Results in both the years (2010 and011) revealed the successive increase in leaf area, spike length, andresh weight by Zn application over the control treatment. The high-st values were observed with 6 mg Zn kg−1; however, differencesmong 4, 6 and 8 mg Zn kg−1 levels were mostly non-significantor these three growth parameters. There was less increase inhese attributes with further enhanced application rate, viz., 10 mgn kg−1. The lowest values were registered under control treat-ent.
.2. Flowering characteristics
Floral attributes were progressively influenced by all the Znoncentrations. However, the earliest flowering and the highestumber of florets per spike were induced by 8 mg Zn kg−1 (Table 1).nder control treatment, flowering took the longest time in both
he years; while 2 mg Zn kg−1 reduced the flowering time non-ignificantly. The lowest florets count and smallest flower sizeere also recorded in the control. The highest florets count and
he largest flower size occurred under 6 mg Zn kg−1 but remainedtatistically at par with other zinc levels.
.3. Bio-chemical attributes
Gladiolus leaf chlorophyll, leaf zinc and flower protein contentsere significantly improved by zinc application as compared to that
n control (Table 2). The highest amounts of chlorophyll contentsere found at 6 mg Zn kg−1, which were statistically similar to
hat with Zn levels of 4 and 8 mg kg−1. Further higher level of zinc10 mg kg−1) did not influence the chlorophyll contents positively.inc contents in leaves increased progressively and significantlyith enhanced Zn application rates over control, and were at theighest with Zn at 10 mg kg−1. Control treatment was found toave critically deficient level of Zn contents in plant tissues. Protein
ontents also improved progressively with increasing zinc concen-ration in the soil media up to 8 mg kg−1, which had statisticallyon-significant difference with Zn levels of 6 and 10 mg kg−1 butemaining significantly higher than in control.
Fig. 1. Effect of various levels of zinc on percent fresh weight change in gladioluscut flowers during 10 days vase life.
3.4. Vase quality parameters
Percentage of opened florets and vase life duration wereenhanced significantly with successive rates of Zn application overcontrol, with the exception of Zn dosage at 10 mg kg−1, whichgave non-significant increase (Table 2). The highest values wereobtained at 6 and 8 mg Zn kg−1, which remained statistically at parwith 2 and 4 mg Zn kg−1. The highest fresh biomass weight of flowerspikes was produced by Zn at 6 mg kg−1 (Fig. 1), which was statisti-cally similar to that with 8 mg Zn kg−1 at the 10th day. Significantlyless membrane leakage was observed with 6 mg Zn kg−1 (Fig. 2) fol-lowed by 8 mg Zn kg−1, over 10 days period. The highest membraneleakage was observed in control.
3.5. Antioxidant enzymes activity
Activities of antioxidative enzymes, viz., SOD (Fig. 3), POD(Fig. 4), CAT (Fig. 5) and free radicals scavenging (Fig. 6) were attheir highest values by the application of Zn at 6 mg kg−1. Furtherhigher levels of Zn did not encourage antioxidative activities. TheSOD activity at 4 and 8 mg Zn kg−1 ranked next to the highest val-ues with Zn at 6 mg kg−1 but both had non-significant difference
15D0 D2 D4 D6 D8 D10
Fig. 2. Effect of various levels of zinc on electrolyte leakage from cell membrane ofgladiolus cut flowers during 10 days vase life.
T. Saeed et al. / Scientia Horticulturae 164 (2013) 124–129 127
Table 1Effect of various zinc levels on the growth and floral attributes of gladiolus plant.
Zinc levels (mg kg−1) Leaf area (cm2) Spike length (cm) Fresh weight (g) Days toflowering (#)
0 30 c 35 c 86 d 96 bc 8.12 c 8.55 d 121 a 119 a 9.50 b 9.25 b 8.32 b 8.62 b2 38 b 39 bc 97 bc 101 ab 9.67 b 10.33 bc 114 abc 116 ab 10.25 a 10.93 a 8.81 ab 8.81 b4 42 a 41 b 103 ab 107 a 9.80 ab 10.67 ab 113 bc 112 bc 10.30 a 10.95 a 9.31 a 9.43 ab6 44 a 45 a 107 a 109 a 10.55 a 11.80 a 117 ab 111 c 10.50 a 10.81 a 9.56 a 10.25 a8 42 a 43 ab 100 b 100 ab 10.00 ab 10.93 ab 109 c 107 c 10.36 a 11.00 a 9.28 a 9.98 a
10 35 b 36 c 92 cd 90 c 8.82 c 9.18 cd 118 ab 117 a 10.20 a 9.85 b 9.31 a 9.56 ab
Table 2Effect of various zinc levels on the biochemical and vase quality attributes of gladiolus plant.
Zinc levels (mg kg−1) Chlorophyll (SPAD value) Zn contents (mg kg−1) Protein (mg g−1) Florets opened (%) Vase life (days)
2010 2011 2010 2011 2010 2011 2010 2011 2010 2011
0 54 c 56 cd 18 e 19 e 0.80 c 0.70 d 2010 2011 2010 20112 60 b 58 bcd 27 d 26 d 1.05 b 1.04 c 80 c 81 b 8.80 c 8.50 bc4 61 ab 61 abc 31 d 33 d 1.14 b 1.10 bc 94 ab 95 a 8.88 c 9.00 abc6 64 a 63 a 46 c 45 c 1.43 a 1.37 a 95 ab 94 a 9.50 bc 10.75 ab8 61 ab 61 ab 57 b 61 b 1.4
10 55 c 55 d 80 a 82 a 1.3
10
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50
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SOD
act
ivit
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Fig. 3. Effect of various levels of zinc on SOD activity in gladiolus cut flowers during10 days vase life.
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Fig. 4. Effect of various levels of zinc on POD activity in gladiolus cut flowers during10 days vase life.
7 a 1.43 a 94 ab 95 a 11.45 a 11.25 a3 a 1.30 ab 98 a 99 a 11.37 ab 11.50 a
and 8 mg Zn kg−1 ranked next and gave statistically higher valuesthan that with control and Zn at 10 mg kg−1 but both had signifi-cant difference before 10th day of shelf life. The POD activity with10 mg Zn kg−1 dropped to the lowest level of control treatment. TheCAT activity in the beginning was at the highest with 8 mg Zn kg−1,later it declined and became statistically similar to that with 6 and10 mg Zn kg−1. Initially, levels of CAT activities were higher withenhanced levels of zinc application up to 8 mg kg−1. Free radicalsscavenging activities in gladiolus cut flowers were greater with 4and 6 mg Zn kg−1 during 10 days study of vase life. Among variouszinc application levels, 10 mg kg−1 rendered the lowest results forantioxidative activities.
4. Discussion
4.1. Plant growth and floral attributes
Zinc supplementation in the growth medium exhibited signifi-cant improvement in the growth and floral attributes of gladiolusindicating its multi-dimensional bio-physiological role in plants. Anoptimum supply of Zn (6–8 mg kg−1 of growth medium) increased
0
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Zn 0 Zn 2 Zn 4 Zn 6 Zn 8 Zn 10
Fig. 5. Effect of various levels of zinc on CAT activity in gladiolus cut flowers during10 days vase life.
128 T. Saeed et al. / Scientia Horticult
65
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ig. 6. Effect of various levels of zinc on free radicals scavenging activity in gladiolusut flowers during 10 days vase life.
he plant growth aspects, viz., leaf area, spike length and fresheight. It was most likely due to involvement of Zn in photosyn-
hesis (Kumar and Haripriya, 2010) as evidenced by enhancementf chlorophyll and protein contents of gladiolus leaves in theurrent study. Furthermore, production of phytohormones in thelants triggered by proper Zn supply (Rashid, 2005) promoteshoot growth especially under thermal stress conditions (Ntatsit al., 2013). On the other hand, excessive Zn application (above
mg kg−1) showed mild toxicity as leaves appeared chlorotic,hich reduced the gladiolus growth as compared to optimum Zn
evel. Woolhouse (1984) has suggested an induced deficiency ofagnesium and iron (integral components of chlorophyll) at ele-
ated Zn levels in the plants. Both, plant growth parameters (leafrea, fresh biomass weight and spike length) and growth con-ributing attributes (chlorophyll and protein contents) of gladiolusxhibited parabolic response to graded Zn doses, being highest at–8 mg Zn kg−1. Our soil had original Zn status of 0.85 mg kg−1
AB-DPTA), and at this level the field crops (except rice) show non-ignificant response to Zn application in calcareous alkaline soils asn Pakistan. Positive response of gladiolus to Zn application up to
mg Zn kg−1 indicates its higher Zn requirement possibly due toaster growth rate, greater biomass production and role in flowerormation.
Exposure of gladiolus plants to Zn resulted in profound effectn flowering time and floral characteristics, rendering early flow-ring with Zn treatment. It could be attributed to the involvementf Zn in the synthesis of plant hormones. Optimum supply ofn exhibits proper hormonal level within plants (Cakmak, 2000),hich induces early maturity and thus causes early flowering
Kumar and Haripriya, 2010). Zinc application also improves theutritional status within plants. Nutrients, sucrose and phytohor-ones move in combination from leaves to shoot apical meristem
o induce early flowering (Aimsworth, 2006). In Zn fertilized plants,heir flower size also increased along with spike length; whereas,n deficient conditions caused stunted flower size. Findings of ourtudy correspond with that of Kumar et al. (2003) who documentedmproved flower size in gladiolus with adequate Zn supply.
.2. Bio-chemical attributes
Present study indicated a significant improvement in chloro-
hyll contents with Zn application. The incremental tend ofhlorophyll could be due to hindered chlorophyll damage eitherue to its role in hampering the photochemical reduction (Kumart al., 1988) or excess accumulation of Fe (Cakmak, 2000). Zinc
urae 164 (2013) 124–129
deficiency reduces the net photosynthesis by disturbing carbonicanhydrase, a key enzyme for CO2 fixation in C4 plants. Contents ofavailable Zn in soil enhanced steadily by increased zinc application;hence, its uptake also improved accordingly. Plants keep very tightcontrol over the internal concentrations of zinc in a process calledzinc homeostasis (Marschner, 1995). Therefore, adequate supplyof Zn looks crucial for proper growth of gladiolus plants and theirdesired flowering characteristics.
In the present study, Zn rendered higher protein contents ingladiolus plants. Lower protein contents as under Zn deficiency arepossibly due to reduced transcription and translation as a resultof enhanced RNA degradation (Khurana and Chatterjee, 2001).Zn maintains the higher level of free amino acids (Singh andBhattacharjee, 1999) within plants. Enhanced membrane stabilityin cut flower spikes leading to stimulated floret opening (as evidentfrom our results) is therefore related to the significance of adequateZn nutrition.
4.3. Vase quality parameters and membrane leakage
Application of Zn extended the display life of gladiolus cutflowers during the vase period. Since cut flowers are prone to desic-cation and oxidative stress during vase life; therefore, Zn being anactivator of certain enzymes, could regulate anti-oxidative activ-ity and membrane stability in the plants under stress. This studydemonstrated the reduced membrane leakage under optimal Znsupply. Zinc prefers binding with sulfohydral group of the mem-brane protein and protects the phospholipids and proteins fromdisulfide formation and thiol oxidation (Aravind and Prasad, 2003).This phenomenon resulted in reduced membrane leakage, andenhanced the vase life of cut flowers.
4.4. Antioxidant enzymes activity
Present experiment revealed the elevated activity of antioxidantenzymes (SOD, POD, CAT) by Zn application. It could be attributed tostrong antioxidative ability of Zn as it is an important component ofZn-SOD and Cu-Zn-SOD, which enhance SOD activity under oxida-tive stress. Similarly, its deficiency in control treatment resulted inreduced SOD activity in gladiolus cut flowers. Aravind and Prasad(2003) documented increase in SOD activity under optimum zincsupply. Zinc application increased the POD activity throughout thevase period. The POD catalyses breakdown of H2O2 into OH− and O−
radicals. Zinc treatment increases the SOD activity which catalysesdismutation of superoxide radicals (O2
−) into H2O2 (Alscher et al.,2002). Zinc induces higher level of H2O2 in plant cells, which mighthave triggered the POD activity. Application of Zn also enhanced theCAT activity and vice versa. Although Zn is not a cofactor requiredin CAT activity, the reason for decrease in CAT activity could be thatZn deficiency is related to inhibition of CAT by O2 (Cakmak andMarschner, 1988).
Free radical scavenging activity (FRSA) was retained at the high-est level of Zn application at medium doses during 10 days periodin vase. Zinc detoxifies ROS including superoxide radical (O2
−) andH2O2, by enhancing SOD activity (Cakmak, 2000). Involvement ofZn in oxidative stress induced gene expression, encoding antioxida-tive defense enzymes system such as H2O2–scavenging ascorbateperoxidase (Alscher et al., 2002) might induce elevated FRSA level.Iron, a producer of powerful oxidant (OH−) is hindered by Zn tocause oxidative damage, either by reducing its uptake or excessiveaccumulation (Cakmak, 2000).
Due to these phenomena and multiple roles of Zn in plants,
its significance in cut flower cultivation/industry is enormous.Mainly, in this study it has been found that Zn bio-availabilitymatters more than its total contents in the soil which might bemisunderstood to be at sufficient level as for field crops. Whereas,
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ut flowers especially the delicate ones like gladiolus, requireigher dose of Zn to maintain their proper growth and enhanceowers’ postharvest life against the oxidative stress.
. Conclusion
Results of this study indicate that Zn has beneficial effects onlant growth, production and floral characteristics of gladiolus cutowers. It extends the vase life and improves the quality of cutowers by enhancing the biochemical attributes, keeping mem-rane stability and increasing the antioxidative enzymes activity.inc application up to 6 mg kg−1 renders the best results for improv-ng growth and quality of gladiolus cut flowers. Zinc applicationbove this rate either gives non-significant improvement or causeseduction in the growth and vase life attributes of gladiolus.
cknowledgements
This study was financially supported by Higher Education Com-ission of Pakistan under HEC Indigenous Ph D 5000 Fellowships
rogram, and technical facilities were provided by PMAS-Arid Agri-ulture University, Rawalpindi, Pakistan.
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