Effects of fertilization and drought stress on tannin biosynthesis of Casuarina equisetifolia seedlings branchlets

Please download to get full document.

View again

of 11
12 views
PDF
All materials on our website are shared by users. If you have any questions about copyright issues, please report us to resolve them. We are always happy to assist you.
Document Description
Effects of fertilization and drought stress on tannin biosynthesis of Casuarina equisetifolia seedlings branchlets
Document Share
Document Tags
Document Transcript
  ORIGINAL PAPER Effects of fertilization and drought stress on tannin biosynthesisof  Casuarina equisetifolia seedlings branchlets Li Hua Zhang • Hong Bo Shao • Gong Fu Ye • Yi Ming Lin Received: 28 September 2011/Revised: 2 February 2012/Accepted: 6 February 2012/Published online: 18 February 2012 Ó Franciszek Go´rski Institute of Plant Physiology, Polish Academy of Sciences, Krako´w 2012 Abstract Nutrient, water, and their interactions influencethe allocation of investment by plants to resistance andtolerance traits. We used a completely crossed randomized-block design experiment to examine the independent andinteractive effects of nutrients and water availability ontannin production of  C. equisetifolia seedlings. The resultsshowed that nitrogen and phosphorus fertilizer have sig-nificant effects on total phenolics (TP) and extractablecondensed tannins (ECT) concentrations of branchlets. TPand ECT concentrations decreased with fertilizer additionand increased in arid condition. This pattern lends tosupport source-sink hypothesis such as the carbon-nutrientbalance (CNB) hypothesis and the growth-differentiationbalance (GDB) hypothesis. Soluble sugars or starch con-centrations were both inversely related to TP concentra-tions. However, there was no significant correlationbetween them and ECT concentrations. In addition, chlo-rophyll concentration had a positive linear correlation withTP and no significant correlation with ECT. On the con-trary, chlorophyll a  /  b ratios were negatively correlated withTP and positively correlated with ECT. The discrepancy of relationship between carbohydrates and TP or ECT showedthat the biosynthetic routes of different tannins were dif-ferent. In this study, no significant correlation between TPand N, or ECT and N, did not support protein competitionmodel (PCM). TP:N and ECT:N ratios were higher innutrient deficiency and arid conditions, which were oneof the important nutrient conservation strategies for C. equisetifolia . Keywords Fertilization Á Drought stress Á Casuarinaequisetifolia Á Tannin Á Secondary metabolism Introduction Phenolic compounds, including tannins, are a significantcomponent of plant secondary metabolites (Izquierdo et al.2011). Estimated to be the fourth most abundant bio-chemical produced by vascular plant tissue after cellulose,hemicellulose, and lignin, tannins represent a significantportion of terrestrial biomass C (Hernes and Hedges2000;Hernes et al.2001). Leaves and bark may contain up to40% tannin by dry weight (Matthews et al.1997; Zhanget al.2009), and in leaves and needles tannin concentra-tions can exceed lignin levels (Hernes et al.2001). On the Communicated by W. Filek.L. H. Zhang Á H. B. ShaoKey Laboratory of Coastal Environmental Processes, YantaiInstitute of Coastal Zone Research (YIC), Chinese Academyof Sciences (CAS), Yantai 264003, People’s Republic of ChinaL. H. Zhang Á H. B. ShaoShandong Provincial Key Laboratory of Coastal ZoneEnvironmental Processes, YICCAS, Yantai 264003,People’s Republic of ChinaH. B. Shao ( & )Institute of Life Sciences, Qingdao University of Scienceand Technology, Zhengzhou Rd.53, Qingdao 266042,People’s Republic of Chinae-mail: shaohongbochu@126.comG. F. Ye ( & )Fujian Academy of Forestry, Fuzhou 350012,People’s Republic of Chinae-mail: yegongfu@126.comY. M. LinKey Lab of Coastal and Wetland Ecosystems,Ministry of Education, and School of Life Sciences,Xiamen University, Xiamen 361005, People’s Republic of China  123 Acta Physiol Plant (2012) 34:1639–1649DOI 10.1007/s11738-012-0958-2  other hand, tannin is widely distributed in plants and ter-restrial ecosystem. Tannins occur in three major terrestrialecosystem pools, including living plant matter, litter, andthe soil. The widespread occurrence and abundance suggestthat tannins play an important role in plant function andevolution, because they are complex and energeticallycostly molecules to synthesize (Cates and Rhoades1977;Zucker1983). In addition to herbivore defense, tanninsplay an important role in a number of ecological processes,including litter decomposition, nutrient cycling, nitrogensequestration, microbial activity, humic acid formation,metal complexation, and pedogenesis (Kraus et al.2003;Shao et al.2008a,b,2009). Vegetable tannin is a consequence of the interactionbetween plants and environments in the long process of plantevolution, so its production is affected by many biotic andabiotic environmental factors, such as nutrient, water, CO 2 ,light, temperature, etc. Two major hypotheses, the carbon–nutrient balance (CNB) hypothesis (Bryant et al.1983) andthe growth–differentiation balance (GDB) hypothesis (Hermsand Mattson1992), have been proposed to predict the effectsof environmental factors on secondary metabolite concen-trations. Both these hypotheses attribute changes in secondarycompound concentrations to changes in resource availability.Protein competition model (PCM) (Jones and Hartley1999),which was presented to predict total phenolics (TP) allocationand concentration in leaves of terrestrial higher plants, statedthat ‘‘protein and phenolics synthesis compete for the com-mon, limiting resource phenylalanine,’’ so nitrogen ratherthan carbon is the limiting resource for synthesis of phenolics.However, they were tested to be correct by some studies andto be incorrect by some others. Casuarina equisetifolia , native to Australia, is a nitro-gen-fixing tree of considerably social, economic, andenvironmental importance in tropical and subtropical lit-toral zones of Asia, the Pacific, and Africa. It is probablythe extensively introduced tree species outside its naturalrange commonly used in agro-forestry systems for soilstabilization and reclamation work and in coastal protec-tion and rehabilitation (Pinyopusarerk and Williams2000). Casuarina trees are planted along the coastal area of theSouth China as windbreaks and for wood and fuelwoodproduction and currently cover about 300,000 hectares(Zhong et al.2010). C. equisetifolia , which is recognized ashigh in tannin and astringent (Okuda et al.1980), grows ininfertile and arid coastal sandy areas. The broad adapt-ability perhaps makes it to be invasive. Despite the wide-spread planting and known ecological and physiologicalproperties, very little has been done to explore secondarymetabolism production in environmental stress conditions.Many previous studies showed that nutrient availability,especially N and P, limits plant growth in most terrestrialecosystems (Koerselman and Meuleman1996; Gu¨sewell2004; Knecht and Goransson2004). In addition, water shortage may also threat the growth of  C. equisetifolia . Theobjective of this study was to determine how moisture,nitrogen, and phosphorus conditions affect the tannin,carbohydrate, chlorophyll, and nutrient concentrations inbranchlets which were obtained from seedlings of  C. equisetifolia exposed to drought and fertilization treat-ments in an outdoor nursery. The relationships betweentannin and carbohydrate, chlorophyll and nitrogen werediscussed to test the CNB, GDB, and PCM hypotheses. Inaddition, this study tries to predict how the tannins affectthe litter decomposition and nutrient dynamics of  C. equisetifolia plantations in infertile and arid conditions. Materials and methods Plant materialWater culture is now the preferred method for the propa-gation of  casuarina cuttings in China. In August 2006,8–10 cm long branchlets of  C. equisetifolia were taken fromstock plants in hedge orchards. The bottom 3–4 cm of thebranchlets was then soaked in water, which was renewedevery day, and the cuttings were placed in bright sunlight(Zhong et al.2010). In September, rooted cuttings weretransplanted in growing containers filled with standard pot-ting mix and transferred to an outdoor nursery to acclimate.In March 2008, 1.5-year-old C. equisetiflolia seedlings weretransplanted into 35 cm 9 28 cm plastic pots containing thesame medium. One seedling was planted per pot. The mostuniform cuttings were sorted into eight blocks, withassignment based on height and number of apical shoots.Experimental designA total of eight treatments (2 moisture levels 9 2 nitrogenlevels 9 2 phosphorus levels), and nine replications wereused in a completely randomized design (total number of pots = 72). Two moisture levels: drought-stressed andwell-watered; two nitrogen levels (g pot - 1 ): 2 and 0; twophosphorus levels (g pot - 1 ): 2 and 0.For the water treatment, plants were watered with 200 mlof tap water per pot once a week (Monday) for the low waterlevel, and 600 ml of tap water per pot per week for the highwater level (Kouki and Manetas2002). A commerciallyavailable fertilizer (urea as nitrogen fertilizer containing46.4% N and superphosphate as phosphorus fertilizer con-taining 12% P 2 O 5 ) was used for the fertilizer treatment. Weapplied approximately 2 g of the fertilizer over a period of 3 months (March–May). This frequency of application notonly allowed for the initial hardening, but also preventedexcessive leaching of the nutrients from the sandy soil. In 1640 Acta Physiol Plant (2012) 34:1639–1649  123  June (day 90) and September (day 180), the seedlingsbranchlets of different treatments were collected to quantifythe effects of nutrient and water availability on tannin con-centrations and other indices with prolonged treatment time.Chemical analysesAll chemicals were of analytical reagent (AR) purity grade.An additional standard denoted here as purified tannin, wasextracted from C. equisetifolia branchlets and purified onSephadex LH-20 (Amersham, USA) according to the pro-cedure previously described by Asquith and Butler (1986)as modified by Hagerman (2002). The CT standard wasfreeze-dried and stored at - 20 ° C until required.Procedures described by Lin et al. (2006) were used todetermine total phenolics (TP), extractable condensedtannins (ECT). TP were measured with the Prussian bluemethod (Graham1992), and ECT were assayed by thebutanol–HCl method (Terrill et al.1992), using purifiedtannins from C. equisetifolia branchlets as the standard.The anthrone method was applied for soluble sugar andstarch determination (Ye and Zhu2007). The chlorophylland carotenoid concentrations were also measured withmethods of Ye and Zhu (2007). The N concentration wasdetermined with Nessler’s reagent after Kjeldahl digestionof powdered samples with sulfuric acid and hydrogenperoxide (Mae et al.1983) and the P concentration wasdetermined by the ascorbic acid–antimony reducing phos-phate colorimetric method (Nanjing Institute of Soil Sci-ence1978).Statistical analysisThe effects of moisture, nitrogen fertilizer, phosphorusfertilizer, treatment time, and their interactions onbranchlets phytochemistry were analyzed using multi-wayANOVA. The relationship between single factor (moisture,nitrogen fertilizer, phosphorus fertilizer, or treatment time)and tannin or other indices were analyzed using partialcorrelation analysis. Correlations among variables weredetermined by linear regression analysis. Significance wasdetermined at P \ 0.05, and where indicated Fisher’s LeastSignificant Difference (LSD) test was used to determinesignificant differences between treatments (Kraus et al.2004). All statistical analyses were performed using SPSS15.0 for Windows. Results Changes of TP and ECT concentrationBranchlets TP concentration significantly increased withdrought stress and prolonged treatment time. On day 90and day 180, branchlets TP concentration ranged from171.29 ± 19.46 to 245.75 ± 16.30 mg g - 1 and from199.25 ± 15.51 to 346.13 ± 24.51 mg g - 1 , respectively(Fig.1). The concentration increased more under drought-stressed treatment than well-watered. Compared with well-watered treatment, TP concentration increased significantlyunder drought stress.    T   P   (  m  g  g  -   1   ) 50100150200250300350400450Drought-stressedWell-watered Fertilized treatment Control N P N+P     E   C   T   (  m  g  g  -   1   ) 0100200300400500 Fertilized treatment Control N P N+P 90 d180 d Fig. 1 Changes in TP andECT concentrations of  C. equisetifolia seedlingsbranchlets in different moistureand fertilized soil treatmentplotsActa Physiol Plant (2012) 34:1639–1649 1641  123  ECT concentration, which is 175.63 ± 23.51–449.84 ± 88.40 mg g - 1 under drought stress and 178.49 ± 78.36–332.04 ± 25.02 mg g - 1 under well-watered treat-ment on day 90, decreased to 146.92 ± 60.67–214.79 ± 11.43 and 77.70 ± 15.07–234.83 ± 79.29 mg g - 1 on day180, respectively (Fig.1). ECT concentration was higherunder drought stress than that under well-watered treatmenton both harvest dates except for the treatment of phos-phorus addition and decreased with prolonged treatmenttime and fertilization.Treatment time, fertilization, and moisture conditionshad significant effects on TP and ECT concentration, buttheir interaction did not affect them significantly exceptTime 9 Moisture and N 9 P 9 Moisture on TP andTime 9 P and P 9 Moisture on ECT (Table1).Changes of soluble sugars and starch concentrationSoluble sugars and starch concentration ranged from54.45 ± 10.84 to 84.90 ± 5.51 mg g - 1 and 10.92 ± 1.06–19.60 ± 3.22 mg g - 1 on day 90, respectively(Fig.2). Their concentrations were higher under drought-stressed than that under well-watered treatment. Whenfertilizers were added, their concentrations decreased underdrought stress and increased under well-watered treatment,respectively. On day 180, there was no significant differ-ence for soluble sugars concentration under two moistureconditions as the concentration increased under well-watered and changed little under drought-stressed treat-ment. On the contrary, starch concentration both increasedwith prolonged treatment time under two moisture condi-tions, so the level of branchlets starch 14.41 ± 3.19–22.54 ± 2.87 mg g - 1 was still higher under drought stress15.27 ± 1.49–18.46 ± 4.14 mg g - 1 than that under well-watered treatment. The treatment time and drought stresshad significant effects on soluble sugars and starch con-centration, while fertilization had no significant effect onthem (Table1).Soluble sugars or starch concentrations were bothinversely related to TP concentrations (Fig.3a, c). How-ever, there is no significant correlation between them andECT concentrations (Fig.3b, d).Changes of chlorophyll, carotenoid concentrationand chlorophyll a  /  b ratioOn day 90, chlorophyll and carotenoid concentrations werehigher under drought stress, but there was no significantdifference between two moisture conditions on day 180(Table2). On the contrary, chlorophyll a  /  b ratio was loweron day 90 and was higher on day 180 under drought stress.Chlorophyll b increased and chlorophyll a  /  b ratio decreasedsignificantly with prolonged treatment time. However, T    a      b      l    e      1     R   e   s   u    l    t   s    f   r   o   m   a   n   a    l   y   s    i   s   o    f   v   a   r    i   a   n   c   e    f   o   r    b   r   a   n   c    h    l   e    t   s   c    h   a   r   a   c    t   e   r    i   z   a    t    i   o   n   o    f      C .   e   q   u    i   s   e    t    i     f   o     l    i   a    s   e   e    d    l    i   n   g   s .    E    f    f   e   c    t   s    f   o   r    t    i   m   e    (   s    h   o   r    t  -    t   e   r   m ,    l   o   n   g  -    t   e   r   m    ) ,   n    i    t   r   o   g   e   n    (    l   o   w ,   m   e    d    i   u   m ,    h    i   g    h    ) ,   p    h   o   s   p    h   o   r   u   s    (    l   o   w ,   m   e    d    i   u   m ,    h    i   g    h    )   a   n    d   m   o    i   s    t   u   r   e    (    d   r   o   u   g    h    t ,   n   o   r   m   a    l    )    t   r   e   a    t   m   e   n    t   s     F   a   c    t   o   r   s    T    P    E    C    T    S   o    l   u    b    l   e   s   u   g   a   r    S    t   a   r   c    h    C    h    l   o   r   o   p    h   y    l    l    a     C    h    l   o   r   o   p    h   y    l    l      b     C   a   r   o    t   e   n   o    i    d    C    h    l   o   r   o   p    h   y    l    l    a     /      b     N    P    T    P   :    N    E    C    T   :    N    T    i   m   e    *    *    *    *    *    *    *    *    *    *    *    *    0 .    4    2    0    *    *    *    0 .    3    5    6    *    *    *    0 .    2    8    7    *    *    *    *    *    *    *    *    *    N    *    *    *    *    0 .    6    9    3    0 .    9    9    1    0 .    7    8    6    0 .    8    8    2    0 .    8    3    7    0 .    7    3    6    0 .    7    8    8    0 .    9    0    8    0 .    3    9    1    *    *    P    *    *    0 .    1    4    5    *    0 .    0    6    6    0 .    4    6    8    0 .    0    5    8    *    *    0 .    0    5    9    *    *    *    *    *    M   o    i   s    t   u   r   e    *    *    *    *    *    *    *    *    *    0 .    1    0    8    0 .    0    9    5    0 .    0    6    6    0 .    3    4    5    0 .    7    5    9    0 .    6    3    5    *    *    *    0 .    1    0    2    T    i   m   e     9     N    0 .    8    8    8    0 .    6    6    8    0 .    3    8    9    0 .    3    4    2    *    0 .    1    7    8    *    *    0 .    5    0    7    0 .    0    9    6    0 .    6    1    3    0 .    4    8    1    T    i   m   e     9     P    0 .    1    5    0    *    *    *    0 .    7    8    1    0 .    5    0    2    0 .    6    0    2    0 .    8    1    8    0 .    5    8    7    0 .    5    3    2    0 .    8    4    6    *    *    *    0 .    8    5    4    *    *    *    T    i   m   e     9     M   o    i   s    t   u   r   e    *    *    *    0 .    6    3    3    *    *    *    0 .    4    9    4    0 .    3    6    9    *    0 .    6    4    9    *    *    *    *    *    *    *    *    *    *    0 .    6    6    2    N     9     P    0 .    1    0    3    0 .    2    3    4    0 .    2    4    3    0 .    0    9    5    0 .    4    7    5    0 .    8    7    5    0 .    2    8    0    0 .    1    7    4    0 .    3    9    9    *    0 .    7    6    0    0 .    3    9    6    N     9     M   o    i   s    t   u   r   e    0 .    5    7    9    0 .    0    9    3    0 .    6    2    2    0 .    6    9    1    0 .    7    6    5    0 .    4    8    3    0 .    7    6    6    0 .    3    7    3    0 .    4    1    7    *    *    0 .    3    7    3    0 .    3    6    8    P     9     M   o    i   s    t   u   r   e    0 .    5    0    5    *    *    *    0 .    2    9    9    *    0 .    3    7    4    *    *    *    0 .    0    5    5    *    *    *    *    *    T    i   m   e     9     N     9     P    0 .    6    9    8    0 .    3    9    2    0 .    2    1    1    *    0 .    9    5    7    0 .    3    3    7    0 .    7    3    3    *    0 .    7    1    8    0 .    3    4    8    0 .    8    1    9    0 .    3    8    0    T    i   m   e     9     N     9     M   o    i   s    t   u   r   e    0 .    5    0    1    0 .    5    6    2    0 .    1    9    3    *    0 .    1    9    2    0 .    1    7    4    0 .    1    6    3    0 .    9    1    5    0 .    2    9    3    *    0 .    6    5    8    0 .    9    8    7    T    i   m   e     9     P     9     M   o    i   s    t   u   r   e    0 .    0    7    4    0 .    0    5    3    0 .    0    5    6    0 .    7    3    0    0 .    9    0    2    0 .    7    8    4    0 .    7    7    6    0 .    2    7    8    0 .    1    4    3    0 .    6    2    4    0 .    1    1    9    *    N     9     P     9     M   o    i   s    t   u   r   e    *    0 .    4    3    3    0 .    1    4    9    0 .    1    4    9    0 .    9    5    4    0 .    0    9    2    0 .    8    4    4    *    *    *    0 .    5    0    8    0 .    2    4    8    0 .    3    1    1    0 .    5    5    2    T    i   m   e     9     N     9     P     9     M   o    i   s    t   u   r   e    0 .    7    5    9    0 .    4    7    0    0 .    4    1    7    0 .    7    1    7    0 .    1    5    8    0 .    1    4    8    0 .    1    7    3    0 .    5    2    2    0 .    8    7    6    0 .    2    0    3    0 .    9    5    6    0 .    4    5    9    *     P      \     0 .    0    5 ,    *    *     P      \     0 .    0    1 ,    *    *    *     P      \     0 .    0    0    1 1642 Acta Physiol Plant (2012) 34:1639–1649  123  fertilization and moisture condition had no significant effecton chlorophyll and carotenoid concentration and chlorophyll a  /  b ratio. On the other hand, there were significant interac-tions between treatment time and nitrogen fertilizer, mois-ture and phosphorus fertilizer on chlorophyll a , carotenoidconcentrations, and chlorophyll a  /  b ratio (Table1).Chlorophyll concentration had a positive linear corre-lation with TP (Fig.4a) and no significant correlation withECT (Fig.4b). On the contrary, chlorophyll a  /  b ratios werenegatively correlated with TP (Fig.4c) and positivelycorrelated with ECT (Fig.4d).Changes of nitrogen and phosphorus concentrationOn day 90, nitrogen concentration 18.81 ± 1.99–24.33 ± 4.42 mg g - 1 increased with fertilization under droughtstress, while fertilizer addition had no significant effect onits concentration 17.67 ± 2.61–20.02 ± 2.56 mg g - 1    S  o   l  u   b   l  e  s  u  g  a  r  s   (  m  g  g  -   1   ) 20406080100120Drought-stressedWell-watered Fertilized treatment Control N P N+P    S   t  a  r  c   h   (  m  g  g  -   1   ) 0510152025 Fertilized treatment Control N P N+P 90 d180 d Fig. 2 Changes in solublesugars and starch concentrationsof  C. equisetifolia seedlingsbranchlets in different moistureand fertilized soil treatmentplots    S  o   l  u   b   l  e  s  u  g  a  r  s   (  m  g  g  -   1   ) 5060708090100110 TP (mg g-1) 100150200250300350    S   t  a  r  c   h   (  m  g  g  -   1   ) 510152025 ECT (mg g-1) 100200300400500600  r = 0.323  P < 0.05 n = 48  r = -0.108  P = 0.467 n = 48  r = 0.593  P < 0.001 n = 48  r = -0.032  P = 0.830 n = 48 90 d180 d BACD Fig. 3 Relationships between a soluble sugar and TP; b soluble sugar and ECT; c starch and TP; d starch andECT for C. equisetifolia seedlings branchletsActa Physiol Plant (2012) 34:1639–1649 1643  123
Similar documents
View more...
Search Related
We Need Your Support
Thank you for visiting our website and your interest in our free products and services. We are nonprofit website to share and download documents. To the running of this website, we need your help to support us.

Thanks to everyone for your continued support.

No, Thanks