OJIP曲線和JIP-test在植物干旱脅迫研究中的應(yīng)用

歡迎關(guān)注「漢莎科學(xué)儀器」微信公眾號(hào)！

1 總述

干旱脅迫對(duì)植物光合效率產(chǎn)生負(fù)面影響，干擾氣孔功能，影響同化物質(zhì)的積累和運(yùn)輸[1,2,3,4,5]。植物受到干旱脅迫會(huì)激活各種機(jī)制避免缺水造成的負(fù)面影響[6,7]。缺水限制了植物碳代謝和光反應(yīng)產(chǎn)物的利用，使得大量吸收的光能不能被轉(zhuǎn)化為化學(xué)能，從而導(dǎo)致PSⅡ受到破壞[3,8,9,10]。此外水分限制同樣會(huì)影響植物葉綠素含量[11,12]。干旱脅迫下大麥植株光合效率的降低可能是由于氮、磷、鉀和鐵元素的缺乏所造成[13]，隨之而來會(huì)造成PSII蛋白脫磷酸化增加，LHCII蛋白（如b4和CP29）快速磷酸化[14]。

1.1 干旱脅迫對(duì)光系統(tǒng)PSII的影響

與PSII相比，PSⅠ對(duì)水分虧缺具有更高的耐受性，只有在極端干旱條件下才會(huì)出現(xiàn)負(fù)面效應(yīng)[15,16,17]。對(duì)幾種生態(tài)型椰子(Cocos nucifera L.)進(jìn)行的試驗(yàn)研究表明，干旱脅迫限制了光能的吸收和PSII的最大量子產(chǎn)率，降低了電子傳輸速度和羧化效率[18]。同樣，在進(jìn)行性干旱期間，桑樹(Morusindica L.)觀察到由于非活性RCs的增加、電子傳遞減少和能量耗散增強(qiáng)而導(dǎo)致的PSII活性降低[19]。在小麥[20,21,22]、橄欖[23]、葡萄[11]以及一些沙漠灌木的葉片中[24,25]也發(fā)現(xiàn)了PSII的最大量子產(chǎn)量下降。
在灌木中，還觀察到CO2同化減少和電子傳輸受到抑制[25]。二氧化碳同化減少可能導(dǎo)致PSII光化學(xué)活性與NADPH需求之間的不平衡。在這種情況下，活性氧(ROS)的產(chǎn)生增加，這可能是PSII對(duì)光破壞敏感性增加的原因[26]。在多數(shù)情況下，葉綠素?zé)晒鉁y(cè)量表明，通過調(diào)整光系統(tǒng)之間的能量分配和激活替代電子流，增強(qiáng)了對(duì)PSII和PSI光化學(xué)的保護(hù)[27,28]。

1.2 干旱脅迫和熱脅迫的關(guān)系

在自然界中，強(qiáng)烈的光照輻射伴隨著高溫和缺水，可能會(huì)發(fā)生慢性光抑制[16]。事實(shí)上，干旱和高溫是影響農(nóng)業(yè)地區(qū)作物生長(zhǎng)和產(chǎn)量的兩大非生物脅迫，眾所周知，它們一般同時(shí)發(fā)生。干旱和熱脅迫的聯(lián)合效應(yīng)與它們單獨(dú)作用時(shí)觀察到的不同，表明這兩種應(yīng)激源以不同的方式影響新陳代謝[29,30,31]。
González Cruz和Pastenes證明，與脅迫敏感大豆品種Arroz Tuscola相比，干旱脅迫下的抗逆性大豆品種Orfeo INIA具有更高的耐熱性。作者討論了葉黃素、脂類和脂肪酸成分在提高大豆葉片耐高溫性中的可能作用。干旱脅迫下葉片與高溫的相互作用對(duì)PSII的影響已被廣泛研究，普遍表明干旱脅迫下使得葉片PSII的熱穩(wěn)定性增強(qiáng)[31,32,33]。
植物的干旱脅迫和熱脅迫之間存在拮抗效應(yīng)。事實(shí)上，可能是由于植物在脅迫環(huán)境下某些滲透調(diào)節(jié)物質(zhì)(如脯氨酸)的積累提高了植物對(duì)高溫的耐受性[34]。此外，如圖1所示，OJIP曲線中K峰消失表明干旱脅迫可能會(huì)增強(qiáng)PSII對(duì)熱脅迫的耐受能力[31]。

圖1.暗適應(yīng)條件下大麥OJIP曲線。大麥培育2周后，無水干旱處理2周。對(duì)照組和干旱處理組離體葉片45℃熱處理10min，適應(yīng)環(huán)境溫度5min后，測(cè)定葉綠素?zé)晒?strong>[31]。

2 干旱脅迫對(duì)植物OJIP曲線和JIP-test參數(shù)的影響

葉綠素?zé)晒釰IP-test方法用于檢測(cè)植物干旱脅迫，可獲取植物組織和器官在水分脅迫條件下光合作用過程的重要信息[4,35,36,37]。而目前，水分脅迫對(duì)植物光合機(jī)構(gòu)影響導(dǎo)致的熒光參數(shù)的變化尚未有統(tǒng)一定論[4,21,22,38]。

2.1 L&K峰

JIP-test方法可作為篩選耐旱性基因型作物品種的有效工具[19,39,40,41]。干旱脅迫可以直接或間接影響植物的光合活性，從而改變?nèi)~綠素?zé)晒鈩?dòng)力學(xué)曲線。OJIP曲線2~3ms的熒光上升階段與原初光化學(xué)反應(yīng)相關(guān)，L峰和K峰可作為評(píng)價(jià)植物耐旱潛力的有力工具[42]。L峰受PSII各組分間能量轉(zhuǎn)移的連通性影響[43]。K峰的出現(xiàn)與放氧復(fù)合體(OEC)的解離相關(guān)[44]。O-L-K-J-I-P熒光瞬態(tài)的測(cè)量和JIP-test可作為干旱脅迫出現(xiàn)前耐旱性和生理紊亂的潛在指標(biāo)。

2.2 性能指數(shù)PI(performance index)

性能指數(shù)PI是OJIP曲線中為人熟知的一個(gè)重要參數(shù)，是植物狀態(tài)和活性的定量參數(shù)。PI由三個(gè)獨(dú)立的表達(dá)式組成：?jiǎn)挝蝗~綠體活性反應(yīng)中心的數(shù)量，原初光化學(xué)反應(yīng)的有關(guān)的表達(dá)式和一個(gè)與電子傳遞相關(guān)的表達(dá)式[45]。因此，PI易受到天線色素活性、捕獲效率和電子傳遞效率發(fā)生的任何輕微變化的影響。PI對(duì)冬小麥的持續(xù)干旱脅迫敏感[46]。根據(jù)干旱脅迫下記錄的PI值評(píng)估的小麥基因型的耐旱性與糧食產(chǎn)量評(píng)定的結(jié)果高度一致[47]。

PI與干旱因子指數(shù)(DFI)密切相關(guān)，能夠顯示不同基因型植物對(duì)干旱反應(yīng)的巨大差異。DFI是指在任意干旱脅迫時(shí)間內(nèi)，干旱引起的PI相對(duì)降低量。Strauss等人于2006年即運(yùn)用相似定義CFI(Chill Factor Index)檢測(cè)不同大豆基因型的耐寒性。DFI還用于10個(gè)大麥品種(圖2)[42]和21個(gè)芝麻突變體種質(zhì)[48]在干旱脅迫下的特性鑒定。利用性能指數(shù)PI和OJIP曲線確定了埃及雙色大麥和高粱**耐性和最敏感的地方品種[49]。這些研究證明在PSII水平上區(qū)分耐旱品種和敏感品種是可能的。

圖2. 10個(gè)大麥品種在連續(xù)兩周干旱脅迫下干旱因子指數(shù)（DFI）與驅(qū)動(dòng)力（DF）的關(guān)系。每個(gè)基因型都由表中代碼表示[42]。

 

2.3 I~P相
干旱脅迫對(duì)植物光合系統(tǒng)產(chǎn)生許多影響。干旱脅迫下ABS/RC比率的增加[41,50]，這可能是由于某些PSII RCs失活或天線尺寸增加所致。RCs的失活是對(duì)光抑制敏感的一個(gè)指標(biāo)。這意味著在干旱時(shí)期，光化學(xué)活動(dòng)會(huì)降低，把吸收的多余的光通過熱耗散進(jìn)行消散。此外干旱脅迫會(huì)影響OJIP曲線中I~P相位的相對(duì)振幅。I~P相為快速葉綠素?zé)晒馍仙�的最慢階段(約30~200 ms)，與質(zhì)體籃素PC+和PSⅠ中P700+的還原相關(guān)[51,52]。I~P相似乎與通過820nm透射測(cè)量的PSⅠ反應(yīng)中心數(shù)量相關(guān)[53]。此外已證明，不同大麥品種I~P相振幅的變化與其耐旱性相關(guān)[53,54]。

2.4 延遲熒光

葉綠素?zé)晒釩hlF是在光合樣品由暗到光轉(zhuǎn)換后發(fā)射的，而延遲熒光則是由光到暗轉(zhuǎn)換期間檢測(cè)得到[55,56,57]。延遲熒光**由Strehler和Arnold于1951年報(bào)道，是由PSII所發(fā)射。DF被認(rèn)為反映了光誘導(dǎo)電荷分離后，還原的初級(jí)電子受體QA-與氧化的電子供體P680+的再復(fù)合。DF誘導(dǎo)曲線的形狀取決于樣品類型及其生理狀態(tài)。同時(shí)測(cè)量葉綠素Chl a熒光(即時(shí)熒光，PF)、延遲熒光DF、在820nm處調(diào)制反射MR820和遠(yuǎn)紅光(735nm)反射RR的試驗(yàn)設(shè)備已開發(fā)出來(Hansatech, M-PEA)，可獲得不同光合反應(yīng)的速率常數(shù)[56]。如圖3，由Golteev等于2013年提出的Σ方案解釋了光合電子傳遞中上述信號(hào)的來源[58]。如圖4，通過該技術(shù)使用M-PEA，Goltsev等于2012年發(fā)現(xiàn)干旱脅迫下QA-的再氧化受到抑制，由PSII至QA的電子傳遞量子產(chǎn)率下降同時(shí)OJIP曲線快相部分受到抑制[59]。

 

圖3. Σ方案解釋光合電子傳遞鏈中PF、DF和mr820信號(hào)來源[58]。 * 方框表示光合結(jié)構(gòu)構(gòu)件。綠色箭頭表示可以測(cè)量的物理信號(hào)，紅色箭頭表示根據(jù)這些信號(hào)重新計(jì)算的電子和能量流。信號(hào)：DF，延遲熒光；PF，即時(shí)熒光；MR，調(diào)制反射；RR，遠(yuǎn)紅光（735nm）反射。 * 電子流：TR，能量俘獲；E21，從PSII天線到PSI的能量遷移（溢出）；ED，來自內(nèi)部供體的水或中間供體（ID）向PSII的電子供應(yīng)；RE，通過PSI到NADP的電子流；CE，環(huán)式電子流。 * RC1*和RC2*分別是PSI和PSII的反應(yīng)中心葉綠素，其他縮略語是光合光反應(yīng)的經(jīng)典Z方案的標(biāo)準(zhǔn)縮寫。

圖4. JIP-test參數(shù)和延遲熒光參數(shù)I1/I2，該數(shù)據(jù)根據(jù)1184組不同含水量離體大豆葉片測(cè)量[59]。 * 雷達(dá)圖顯示了根據(jù)不同RWC的葉片計(jì)算出的參數(shù)。對(duì)于每個(gè)組，取50片相似RWC的葉片測(cè)量值的平均值，并標(biāo)準(zhǔn)化為100%RWC時(shí)的值。 * I1/I2是DF延遲熒光誘導(dǎo)曲線快速階段延遲熒光最大振幅的比值[60]。雷達(dá)圖生動(dòng)地表示了干旱對(duì)光合機(jī)械的影響。每一個(gè)干旱等級(jí)都由一個(gè)多邊形表示，其角點(diǎn)對(duì)應(yīng)于相對(duì)（相對(duì)于對(duì)照全水化葉的值）JIP參數(shù)，以及DF（I1/I2）誘導(dǎo)曲線上的兩個(gè)峰值的比值。這個(gè)比率I1/I2被發(fā)現(xiàn)與PSII中的電子流成反比[61]。光合機(jī)構(gòu)的功能狀態(tài)可以看作是一個(gè)幾何圖形，其形狀是干旱脅迫所特有的。它對(duì)不同的干旱程度很敏感，所選參數(shù)的雷達(dá)圖可直接用于RWC的經(jīng)驗(yàn)預(yù)測(cè)。

本文內(nèi)容源自《Emerging Technologies and Management of Crop Stress Tolerance A Sustainable Approach》Volume 2，Edited by Parvaiz Ahmad and Saiema Rasool. 

CHAPTER 15——Kalaji H M ,  Jajoo A ,  Oukarroum A , et al. The Use of Chlorophyll Fluorescence Kinetics Analysis to Study the Performance of Photosynthetic Machinery in Plants[J]. Emerging Technologies and Management of Crop Stress Tolerance, 2014:347-384.

參考文獻(xiàn)：

[1] Monteiro,J., Prado, C., 2006. Apparent carboxylation efficiency and relative stomataland mesophyll limitations of photosynthesis in an evergreen cerrado speciesduring water stress. Photosynthetica 44 (1), 39 - 45.

[2] Rampino,P., Pataleo, S., Gerardi, C., Mita, G., Perrotta, C., 2006. Drought stressresponse in wheat: physiological and molecular analysis of resistant andsensitive genotypes. Plant Cell Environ. 29 (12), 2143 - 2152.

[3] Yin, C.,Berninger, F., Li, C., 2006. Photosynthetic responses of Populus przewalskisubjected to drought stress. Photosynthetica 44 (1), 62 - 68.

[4] Hura,T., Grzesiak, S., Hura, K., Thiemt, E., Tokarz, K., We˛dzony, M., 2007.Physiological and biochemical tools useful in drought - tolerance detection ingenotypes of winter triticale: accumulation of ferulic acid correlates withdrought tolerance. Ann. Bot. 100 (4), 767 - 775.

[5] Zhou,Y., Lam, H.M., Zhang, J., 2007. Inhibition of photosynthesis and energydissipation induced by water and high light stresses in rice. J. Exp. Bot. 58(5), 1207 - 1217.

[6] Medrano,H., Escalona, J., Bota, J., Gulias, J., Flexas, J., 2002. Regulation ofphotosynthesis of C3 plants in response to progressive drought: stomatalconductance as a reference parameter. Ann. Bot. 89 (7), 895 - 905.

[7] Chaves,M., Oliveira, M., 2004. Mechanisms underlying plant resilience to waterdeficits: prospects for water - saving agriculture. J. Exp. Bot. 55 (407), 2365- 2384.

[8] Matorin,D., Ortoidze, T., Nikolaev, G., Venediktov, P., Rubin, A., 1982. Effects ofdehydration on electron transport activity in chloroplasts [peas].Photosynthetica 16 (2), 226 - 233.

[9] Cornic,G., Massacci, A., 1996. Leaf photosynthesis under drought stress. In: Baker,N.R. (Ed.), Photosynthesis and the Environment. Kluwer Academic Publishers, pp.347 - 366.

[10] Mullet,J.E., Whitsitt, M.S., 1996. Plant cellular responses to water deficits. PlantGrowth Regulator 20, 119 - 124.

[11] Wright,H., DeLong, J., Lada, R., Prange, R., 2009. The relationship between waterstatus and chlorophyll a fluorescence in grapes (Vitis spp.). Postharvest Biol.Technol. 51 (2), 193 - 199.

[12] Zheng,C., Jiang, D., Liu, F., Dai, T., Jing, Q., Cao, W., 2009. Effects of salt andwaterlogging stresses and their combination on leaf photosynthesis, chloroplastATP synthesis, and antioxidant capacity in wheat. Plant Sci. 176 (4), 575 -582.

[13] Hussein,M.M., Abd El - Kader, A.A., Mona, A.M.S., 2009. Mineral status of plant shootsand grains of barley under foliar fertilization and water stress. Res. J.Agric. Biol. Sci. 5, 108 - 115.

[14] Liu, W.- J., Chen, Y. - E., Tian, W. - J., Du, J. - B., Zhang, Z. - W., Xu, F., etal., 2009. Dephosphorylation of photosystem II proteins and phosphorylation ofCP29 in barley photosynthetic membranes as a response to water stress. Biochim.Biophys. Acta 1787 (10), 1238 - 1245.

[15] VanRensburg, L., Krüger, G.,1993. Differential inhibition of photosynthesis (in vivo and in vitro), andchanges in chlorophyll a fluorescence induction kinetics of four tobaccocultivars under drought stress. J. Plant Physiol. 141 (3), 357 - 365.

[16] Souza,R.P., Machado, E.C., Silva, J.A.B., Lagaa, A.M.M.A.,Silveira, J.A.G., 2004. Photosynthetic gas exchange, chlorophyll fluorescenceand some associated metabolic changes in cowpea (Vigna unguiculata)during water stress and recovery. Environ. Exp. Bot. 51 (1), 45 - 56.

[17] Lauriano,J.A., Ramalho, J.C., Lidon, F.C., C′eu matos, M., 2006. Mechanisms of energydissipation in peanut under water stress. Photosynthetica 44 (3), 404 - 410.

[18] Gomes,F.P., Oliva, M.A., Mielke, M.S., de Almeida, A - AF, Leite, H.G., Aquino, L.A.,2008. Photosynthetic limitations in leaves of young Brazilian Green Dwarfcoconut (Cocos nucifera L. “nana”) palm under well - watered conditions orrecovering from drought stress. Environ. Exp. Bot. 62 (3), 195 - 204.

[19] Guha,A., Sengupta, D., Reddy, A.R., 2013. Polyphasic chlorophyll a fluorescencekinetics and leaf protein analyses to track dynamics of photosyntheticperformance in mulberry during progressive drought. J. Photochem. Photobiol. B,Biol. 119, 71 - 83.

[20] Paknejad,F., Nasri, M., Moghadam, H.R.T., Zahedi, H., Alahmadi, M.J., 2007. Effects ofdrought stress on chlorophyll fluorescence parameters, chlorophyll content andgrain yield of wheat cultivars. J. Biol. Sci. 7, 841 - 847.

[21] Guóth, A.,Tari, I., Gall′e, A′., Csisz′ar, J., Horv′ath, F., P′ecsv′aradi, A., Cseuz, L.,Erdei, L., 2009a. Chlorophyll a fluorescence induction parameters of flagleaves characterize genotypes and not the drought tolerance of wheat duringgrain filling under water deficit. Acta Biol. Szeged. 53, 1 - 7.

[22] Guóth,A., Tari, I., Gall′e, A′., Csisz′ar, J., P′ecsv′aradi, A., Cseuz, L., Erdei,L., 2009b. Comparison of the drought stress responses of tolerant and sensitivewheat cultivars during grain filling: changes in flag leaf photosyntheticactivity, ABA levels, and grain yield. J. Plant Growth Regul. 28 (2), 167 -176.

[23] Sofo,A., Dichio, B., Montanaro, G., Xiloyannis, C., 2009. Photosynthetic performanceand light response of two olive cultivars under different water and lightregimes. Photosynthetica 47 (4), 602 - 608.

[24] Hamerlynck,E.P., Huxman, T.E., 2009. Ecophysiology of two Sonoran Desert evergreen shrubsduring extreme drought. J. Arid Environ. 73 (4 - 5), 582 - 585.

[25] Peeva,V., Cornic, G., 2009. Leaf photosynthesis of Haberlea rhodopensis before andduring drought. Environ. Exp. Bot. 65 (2 - 3), 310 - 318.

[26] Ohashi,Y., Nakayama, N., Saneoka, H., Fujita, K., 2006. Effects of drought stress onphotosynthetic gas exchange, chlorophyll fluorescence and stem diameter ofsoybean plants. Biol. Plant. 50 (1), 138 - 141.

[27] Zivcak,M., Olsovska, K., Brestic, M., Slabbert, M.M., 2013. Critical temperaturederived from the selected chlorophyll a fluorescence parameters of indigenousvegetable species of South Africa treated with high temperature. PhotosynthesisResearch for Food, Fuel and the Future. Springer, Berlin Heidelberg, pp. 628 -632.

[28] Zivcak,M., Brestic, M., Balatova, Z., Drevenakova, P., Olsovska, K., Kalaji, H.M., etal., 2013. Photosynthetic electron transport and specific photoprotectiveresponses in wheat leaves under drought stress. Photosynth. Res. 117, 529 -546.

[29] Dobra,J., Motyka, V., Dobrev, P., Malbeck, J., Prasil, I.T., Haisel, D., et al.,2010. Comparison of hormonal responses to heat, drought and combined stress intobacco plants with elevated proline content. J. Plant Physiol. 167 (16), 1360- 1370.

[30] Silva,E.N., Ferreira - Silva, S.L., Fontenele, A.d.V., Ribeiro, R.V., Vi′egas, R.A.,Silveira, J.A.G., 2010. Photosynthetic changes and protective mechanismsagainst oxidative damage subjected to isolated and combined drought and heatstresses in Jatropha curcas plants. J. Plant Physiol. 167 (14), 1157 - 1164.

[31] Oukarroum,A., El Madidi, S., Strasser, R., 2012. Exogenous glycine betaine and proline playa protective role in heat - stressed barley leaves (Hordeum vulgare L.): achlorophyll a fluorescence study. Plant Biosyst. 146 (4), 1037 - 1043.

[32] Havaux,M., 1992. Stress tolerance of photosystem II in vivo antagonistic effects ofwater, heat, and photoinhibition stresses. Plant Physiol. 100 (1), 424 - 432.

[33] Lu, C.,Zhang, J., 1999. Effects of water stress on photosystem II photochemistry andits thermostability in wheat plants. J. Exp. Bot. 50 (336), 1199 - 1206.

[34] Ashraf,M., Foolad, M., 2007. Roles of glycine betaine and proline in improving plantabiotic stress resistance.Environ. Exp. Bot. 59 (2), 206 - 216.

[35] Bolhàr -Nordenkampf, H., Ö quist, G., 1993. Chlorophyllfluorescence as a tool in photosynthesis research. In: Hall, D.O., Scurlock,J.M.O., Bolhàr - Nordenkampf, H.R., Leegood, R.C., Long, S.P. (Eds.),Photosynthesis and Production in a Changing Environment: A Field and LaboratoryManual. Chapman and Hall, London, UK, pp. 193 - 206.

[36] Schweiger,J., Lang, M., Lichtenthaler, H.K., 1996. Differences in fluorescence excitationspectra of leaves between stressed and non - stressed plants. J. Plant Physiol.148 (5), 536 - 547.

[37] Yordanov,I., Tsonev, T., Goltsev, V., Kruleva, L., Velikova, V., 1997. Interactiveeffect of water deficit and high temperature on photosynthesis of sunflower andmaize plants. 1. Changes in parameters of chlorophyll fluorescence inductionkinetics and fluorescence quenching. Photosynthetica 33 (3 - 4), 391 - 402.

[38] Munné -Bosch, S., Falara, V., Pateraki, I., Lo′pez - Carbonell, M., Cela, J.,Kanellis, A.K., 2009. Physiological and molecular responses of the isoprenoidbiosynthetic pathway in a drought - resistant Mediterranean shrub, Cistuscreticus exposed to water deficit. J. Plant Physiol. 166 (2), 136 - 145.

[39] VanRensburg, L., Kruger, G., Eggenberg, P., Strasser, R., 1996. Can screeningcriteria for drought resistance in Nicotiana tabacum L be derived from thepolyphasic rise of the chlorophyll a fluorescence transient (OJIP)? S. Afr. J.Bot. 62 (6), 337 - 341.

[40] Oukarroum,A., El Madidi, S., Strasser, R.J., 2006. Drought stress induced in barleycultivars (Hordeurn vulgare L.) by polyethylene glycol, probed bygermination, root length and chlorophyll a fluorescence rise (OJIP). Arch. Sci.59 (1), 65 - 74.

[41] Gomes,M.T.G., da Luz, A.C., dos Santos, M.R., do Carmo Pimentel Batitucci, M., Silva,D.M., Falqueto, A. R., 2012. Drought tolerance of passion fruit plants assessedby the OJIP chlorophyll a fluorescence transient. Sci. Hortic. 142, 49 - 56.

[42] Oukarroum,A., Madidi, S.E., Schansker, G., Strasser, R.J., 2007. Probing the responses ofbarley cultivars (Hordeum vulgare L.) by chlorophyll a fluorescenceOLKJIP under drought stress and re - watering. Environ. Exp. Bot. 60 (3), 438 -446.

[43] Strasser,R.J., Stirbet, A.D., 1998. Heterogeneity of photosystem II probed by thenumerically simulated chlorophyll a fluorescence rise (O - J - I - P). Math.Comput. Simul. 48 (1), 3 - 9.

[44] Guissé,B., Srivastava, A., Strasser, R., 1995. The polyphasic rise of the chlorophylla fluorescence (OKJIP) in heat stressed leaves. Arch. Sci. Geneve 48, 147 -160.

[45] Strasser,R.J., Tsimilli - Michael, M., Srivastava, A., 2004. Analysis of the chlorophylla fluorescence transient. In: Papageorgiou, G., Govindjee (Eds.), Advances inPhotosynthesis and Respiration. Chlorophyll a Fluorescence: A Signature ofPhotosynthesis. Springer, Dordrecht, The Netherlands, pp. 321 - 362.

[46] Zivcak,M., Brestic, M., Olsovska, K., Slamka, P., 2008. Performance Index as asensitive indicator of water stress in Triticum aestivum. Plant Soil Environ.54, 133 - 139.

[47] Zivcak,M., Brestic, M., Olsovska, K., 2008. Physiological parameters useful inscreening for improved tolerance to drought in winter wheat (Triticum aestivumL.). Cereal Res. Commun. 36, 1943 - 1946.

[48] Boureima,S., Oukarroum, A., Diouf, M., Cisse, N., Van Damme, P., 2012. Screening fordrought tolerance in mutant germplasm of sesame (Sesamum indicum) probing bychlorophyll a fluorescence. Environ. Exp. Bot. 81, 37 - 43.

[49] Jedmowski,C., Ashoub, A., Bru¨ggemann, W., 2013. Reactions of Egyptian landraces ofHordeum vulgare and Sorghum bicolor to drought stress, evaluated by the OJIPfluorescence transient analysis. Acta Physiol. Plant. 35 (2), 345 - 354.

[50] VanHeerden, P.D.R., Swanepoel, J.W., Kru¨ger, G.H.J., 2007. Modulation ofphotosynthesis by drought in two desert scrub species exhibiting C3- mode CO2 assimilation. Environ. Exp. Bot. 61 (2), 124 - 136.

[51] Schreiber,U., Neubauer, C., Klughammer, C., 1989. Devices and methods for room -temperature fluorescence analysis. Philos. Trans. R. Soc. Lond., B, Biol. Sci.323 (1216), 241 - 251.

[52] Schansker,G., Srivastava, A., Govindjee, Strasser, R.J., 2003. Characterization of the820 - nm transmission signal paralleling the chlorophyll a fluorescence rise (OJIP)in pea leaves. Funct. Plant Biol. 30 (7), 785 - 796.

[53] Ceppi,M.G., Oukarroum, A., C¸ ic¸ek, N., Strasser, R.J., Schansker, G., 2012. The IPamplitude of the fluorescence rise OJIP is sensitive to changes in thephotosystem I content of leaves: a study on plants exposed to magnesium andsulfate deficiencies, drought stress and salt stress. Physiol. Plant. 144 (3),277 - 288.

[54] Oukarroum,A., Schansker, G., Strasser, R.J., 2009. Drought stress effects on photosystemI content and photosystem II thermotolerance analyzed using Chl a fluorescencekinetics in barley varieties differing in their drought tolerance. Physiol.Plant. 137 (2), 188 - 199.

[55] Goltsev,V., Zaharieva, I., Chernev, P., Strasser, R.J., 2009. Delayed chlorophyllfluorescence as a monitor for physiological state of photosynthetic apparatus.Biotechnol. Biotechnol. Equip. 23, 452 - 457 (special edition).

[56] Strasser,R.J., Tsimilli - Michael, M., Qiang, S., Goltsev, V., 2010. Simultaneous invivo recording of prompt and delayed fluorescence and 820 - nm reflectionchanges during drying and after rehydration of the resurrection plant Haberlearhodopensis. Biochim. Biophys. Acta 1797, 1313 - 1326.

[57] Kalaji,H.M., Carpentier, R., Allakhverdiev, S.I., Bosa, K., 2012. Fluorescenceparameters as early indicators of light stress in barley. J. Photochem.Photobiol. B, Biol. 112, 1 - 6.

[58] Goltsev,V., Gurmanova, M., Kouzmanova, M., Yordanov, I., Qiang, S., Pentland, A., etal., 2010. Analysis of dark drops, dark - induced changes in chlorophyllfluorescence during the recording of the OJIP transient. In: Kuang, T., Lu, C.,Zhang, L. (Eds.), Photosynthesis Research for Food, Fuel and Future. Springer -Verlag, Berlin, Heidelberg, pp. 179 - 183.

[59] Goltsev,V., Zaharieva, I., Chernev, P., Kouzmanova, M., Kalaji, H.M., Yordanov, I., etal., 2012. Drought - induced modifications of photosynthetic electron transportin intact leaves: analysis and use of neural net - works as a tool for a rapidnon - invasive estimation. Biochim. Biophys. Acta 1817 (8), 1490 - 1498.

[60] Goltsev,V., Chernev, P., Zaharieva, I., Lambrev, P., Strasser, R.J., 2005. Kinetics ofdelayed chlorophyll a fluorescence registered in milliseconds time range.Photosynth. Res. 84, 209 - 215.

[61] Zaharieva,I., Taneva, S.G., Goltsev, V., 2001. Effect of temperature on the luminescentcharacteristics in leaves of Arabidopsis mutants with decreased unsaturation ofthe membrane lipids. Bulg J. Plant Physiol. 27, 3 - 19.