types and mechanism of stay green with case studies

1. STAY-GREEN TRAIT IN CROPS
PresentedBy
RANJANI M S
PhDScholar
Genetics and Plant Breeding
TNAU 1

2. Content Introduction
History
Significance of stay -green trait
Types of stay-green
Relationship between chlorophyll and stay-green
Carbon capture/nitrogen remobilization and stay green
Hormones and stay-green
Transcription factors and stay-green
Breeding for stay-green trait
Stay-green in different crops
Ideotype of stay green plants
Case studies
Conclusion
2

3. Fig. Changes in the climate and the potential
impacts of these changes on crop yields,
according to the fifth assessment report (5AR) of
Intergovernmental Panel on Climate Change
(IPCC)
Abdelrahmanet al.,(2017)
Introduction
3

4. • Heritable delayed foliar senescence character in crops.
• Extended foliar greenness even under post-anthesis drought.
• genotypes possessing this trait maintain more photosynthetically
active leaves than genotypes not possessing this trait ..
• Therefore they are expected to give a higher production and
productivity of grain as well biomass under biotic and abiotic
stress condition.
STAY-GREEN
4

5. History
• The earliest record of stay-green was found in broad bean
varieties in 1962 (Steinbuch et al.).
• Stay-green lines of broad bean had a uniform seed size and
could be harvested at a more mature stage than the very late
white varieties.
• stay-green seems originally to have been a phenotype
descriptor used by legume breeders (Thomas et al. 1996 )
5

6. History
• Sjodin (1971) claimed stay-green as a character in Viciafaba.
• Intensive selectionhad been steadily increasing both yield and
the duration of greennessin a range of agricultural species
since the early decades of the 20th century (Duvick et al., 2004).
• By the end of the 1970s, stay-green was becoming established
explicitly as a superior characteristic and marketing feature of
commercially bred grain crops, particularly maize.
6

7. Duvick et al., 2004
Fig. Progressive increases in yields and stay-green scores of modern maize varieties since
1930
7

8. Significance of stay-green trait
• Nitrogen remobilization during grain filling
• Drought and lodging resistance
• Enhancing the fodder improvement
• Silage making quality
• Increases market value in horticultural crops
8

9. Types of stay-green
• Type A:senescence is initiated late but then proceeds at a normal rate.
• Type B: initiate senescence on schedule, but thereafter senesce comparatively slowly.
• Type C: the syndrome may begin and proceed on schedule but one or more of the constituent
metabolic processes may be disabled .
• Type D : represents the case of plant material such as herbarium specimens or frozen foods
which retain greenness because they are rapidly killed at harvest.
• Type E : the photosynthetic capacity of an intensely green genotype may follow the normal
ontogenic pattern, but comparison of absolute pigment identifies it as a stay-green. 9

10. ThomasandHowarth( 2000)10

11. Classification of stay-green
Thomasand Howarth ( 2000)
11

12. 12

13. Chlorophyll Breakdown Pathway in Higher Plants
Hortensteiner, 200913

14. CCEs( Chlorophyll
catabolic enzymes )
Stay-green
• SGR
• NYE 1
• SID
Chlorophyll b reductase
• NYC
• NOL
• HCAR
Mg dechelatase
• NYE1/SGR1
Phaeophytinase
• PPH
• CRN1
• NCY3
Phaeophorbide a
oxygenase
• RAO
• ACD1
• LLS1
RCC reductase
• RCCR
• ACD2
Thomasand Oughum2014 14

15. Relationship
between
chlorophyll and
stay-green
• Defects in chlorophyll degradation are a cause of delayed
leaf senescence.
• In many plant species, stay-green mutants have been
identified that show retention of Chlorophyll during
senescence.
• The SGR proteins are generally classified into two distinct
subfamilies named as SGR and SGR-like (SGRL), both of
which exist in both monocotyledonous and
dicotyledonous plants.
• SGR proteins from different species are highly similar
and localize to the chloroplast’s thylakoid membrane
15

16. • Arabidopsis thaliana encodes 3 SGRs namely SGR1/NYE1, SGR2/NYE2and SGRL.
• Above gene products destabilize protein-pigment complexes and increase the availability of
chlorophyll for cleavage by CCEs .
• The physical interactions between CCEs and light-harvesting complexes (LHCs) is the main
reason for degradation of Chlorophyll.
16

17. Chlorophyll
degradation in
Arabidopsis thaliana
SGR1, SGRL – Positive regulation
SGR2 – negative regulation
SGRL – Expressed in developmental stage
SGR- expressed during senescence only
17

18. • SGRL degrades chlorophyll into pheophytina and
pheophorbide a
• SGR degrades chlorophyll a to pheophytin a.
• Both subfamilies do not use chlorophyll b as substrate.
• Chlorophyll b tightly holds Mg.
• SGR extract Mg from chlorophyll b.
• Over expression of
• SGR1-leaf yellowing
• Sgr1 mutant-STAY-GREEN
• SGR2-STAY-GREEN
• Sgr2-Premature leaf senescence
18

19. SGR1-CCE-LHCII complex
LHCII
6 CCEs
SGR1
Chlorophyll degradation
• Binding affinity of SGR2 for CCE is much lower
than for SGR1.
• Hetero-dimerization of SGR1& SGR2 can
obstruct SGR1 and CCEs interactions, limiting
the SGR1–CCE–LHCII protein complex
formation and finally chlorophyll degradation.
Das et al., 2018 19

20. Plant Senescence and Productivity
• Senescence is a developmental process which in annual crop plants overlaps with the reproductive phase.
• Senescence might reduce cropyield when it is induced prematurely under adverse environmental conditions.
• The senescence can be classified as monocarpicand polycarpic.
• Cultivars with delayed senescence characteristics (‘stay-green’ phenotypes) are functional stay-green plants
with increased productivity, i.e. higher biomass or grain/seed yields.
• Modulationof the senescence process is part of the adaptation of crop plants to different environmental
conditions, in particular to drought stress.
Gregerson et al.,201320

21. Causes for senescence
• Age or developmental senescence
• Stress-induced senescence
• Dark/shade
• Heat/light
• Drought
• Low nitrogen supply
• Biotic stress
Gregersenet al.,201321

22. The senescence
window concept
Schippers et al., (2015)22

23. Overview of nutrient remobilization and
transport during developmental and
precocious senescence
Schippers et al., (2015)23

24. Schematic diagramshowing
integrative effect of stay-green
and terminal senescence traits
in plants
Jagadish et al., 201524

25. Carbon capture/nitrogen remobilization and stay green
• Leaf at young stage – Sink for Carbon (C), nitrogen (N) and other nutrients.
• After proper development - Contributor of photosynthates.
• C-capture phase is followed by N-remobilization phase.
• Carbon and Nitrogen cease in the terminal phase of leaf death.
25

26. • The transition from the period of C capture to that of N remobilization corresponds to the
functional initiation of senescence.
• Functional stay-greens are genotypes in which the C–N transition point is delayed, or the
transition occurs on time but subsequent yellowing and N remobilization run slowly.
Thomas and Oughum ,(2014)26

27. Thomas and Oughum,(2014)
Fig. The functional stay-green trait is
associated with the transition from the carbon
(C) capture to the nitrogen (N) mobilization
phase of foliar development.
N mobilization in functional stay-greens
27

28. Osaki et al., (1991)
28

29. N mobilization in cosmetic stay-greens
• Cosmetic stay-greens have little significant influence on the C-capture phase of foliar
development.
• Extended lifespan of chlorophyll – retention of the membrane proteins with which
chlorophyll is associated in chloroplast.
• Thylakoid proteins are second only to ribulose-1,5-bisphosphate carboxylase-oxygenase
(Rubisco) as a source of remobilized N during senescence.
29

30. • Primary sites of the genetic lesion - chlorophyll
catabolism
• Disruption of membrane organization and of
protein recycling are pleiotropic consequences of
this class of mutation.
• Species with high-N sinks - the demands of
developing vegetative tissue or grains can be met
by N recycled from Rubisco and other soluble
proteins
Thomasand Oughum,(2014) 30

31. Protein
catabolism and
N recycling
CND41
• encodes aspartic protease
• degrades RUBISCO
• accelerates yellowing in tobacco
• antisense suppression delays senescence
See2β
• Proteolytic enzymes generally accelerates senescence
• Transposon insertion retain chlorophyll and
photosynthetic activity for longer
Thomas and Oughum ,(2014)31

32. Hormones and stay-green
Abdelrahman et al.,2017
Fig. A model depicting the ethylene biosynthesis and
downstream signalling pathways that regulate leaf senescence
in Arabidopsis plants under heat stress.
32

33. Abdelrahman et al.,2017
Fig. model depicting the strigolactone (SL) and cytokinin (CK)
pathways, and the involvement of abscisic acid (ABA) and
ethylene, in the regulation of leaf senescence in Arabidopsis
plants under heat stress.
33

34. Jasmonicacid
• JA promotes leaf senescence during a dark treatment
• mutant of COI1 encoding the co-receptor of JA and the antisense transgenic plant of 3-
ketoacyl-CoA thiolase 2 (KAT2) involved in JA synthesis have a stay-green phenotype in
response to a dark Incubation.
Brassinosteroids
• DET2 encodes a steroid 5a-reductase that catalyzes an early step of BR synthesis.
• mutant det2 shows a stay-greenphenotype
• mutant of BZR2/ BES1, a transcription factor positively regulating BR signaling, also
shows a stay-green phenotype
Kusabaet al.,(2013)
34

35. Auxin
• gene (YUCCA6)-coding rate-limiting enzyme of auxin synthesis-positively regulates stay-
greenphenotype.
• a mutant of the auxin-inducible gene Small Auxin Up RNA 36(SAUR36) has been
reported to show a stay-green phenotype.
• mutant of auxin response factor 2 (ARF2)is reported to have a stay-greenphenotype
Kusabaet al.,(2013)
35

36. Transcription factors and stay-green
NAC transcriptionfactors
• Among families of plant transcription factors, the NAC family contains a number of
senescence-inducible genes.
ORE1, ORS1
• In Arabidopsis, ORE1 and ORS1 –positive regulators of leaf senescence.
• ORE1 target-bifunctional nuclease 1(Senescence inducible gene)
• miR164 regulates mRNA of ORE1 and ORS1 during young stages
Kusabaet al.,(2013)36

37. ORE1, ORS1
• GARP Nuclear transcription factors - Golden2-like 1 (GLK1) and GLK2-chloroplast development.
• ORE1 binds to GARP Nuclear transcription factors promoting senescence.
AtNAP
• AtNAP binds the promoter of SAG113 and regulates its expression
• Mutant of AtNAP delayed senescence
• ORE and AtNAP are positive regulators of leaf senescence
• VNI and JUB are negative regulators of leaf senescence
Senescence-inducible negative regulators are thought to work in concert with positive regulators
to finetune leaf senescence.
Kusabaet al.,(2013)37

38. WRKYtranscription factors
• WRKY53 – positive regulator of leaf senescence
• Epithiospecifying senescence regulator(ERS) and WRKY53 function antagonistically in leaf
senescence.
• WRKY53- induced by Salicylic acid and repressed by Jasmonic acid
• ERS – induced by Jasmonic acidand repressed by salicylic acid
• ERS interacts with WRKY53 and prevents DNA binding of WRKY53
• Accumulation of SA promotes leaf senescence through SA signalling pathway.
• WRKY22-positive regulator of leaf senescence
• WRKY54 and WRKY70- negative regulator of leaf senescence
Kusabaet al.,(2013)38

39. These positive and negative regulators may fine
tune the regulation of leaf senescence through
their complex interaction, including mutual
transcription activation or heterodimer
formation .
Kusabaet al.,(2013)39

40. Mechanism of tolerance in stay-green
• Several stay-green trait & loci are mapped for droughtresponse.
• Physiological mechanisms
• Xylem pressure potential – grain yield – stay-green traits are associated
• QTL for xylem pressure potential influences drought tolerance by maintaining plant
water status.
• Delayed loss of photosynthetic capacity or enhanced uptake of N in post anthesis leads to
drought tolerance.
• Understanding the source-sink basis of annuality & perenniality.
• For better understanding syntenic relation with model species such as rice can be done
40

41. Region of the rice genome (from 28 to 37.1 Mb on chromosome 1) corresponding to the sorghum stay-green QTL Stg1, showing
several rice QTLs affecting source quality. (Srinivas et al., 2008) 41

42. “STAY-GREEN” traits for optimizing yields in crop plants suffering
heat and/or drought stress(es) at anthesis or post-anthesis
• “STAY-GREEN” trait for increased yield -drought and/or heat stress -wheat, sorghum, barley
(Hordeumvulgare), rice, maize (Zeamays) and cowpea (Vignaunguiculata).
• “STAYGREEN” genotypes - high photosynthetic activities under heat or drought stress,
resulting in high yields, mostly due to a reduction in reproductive organ sterility and a
subsequent improvement in grain numbers.
• In wheat grown under drought conditions, drought-tolerant genotypes accumulated large
amounts of carbohydrates in the reproductive organs, despite continuing to supply
carbohydrates to the anthers.
42

43. • inhibited cell wall invertase activity during microspore development –pollen abortion
• Invertase was highly active in the anther tapetum of drought-tolerant wheat lines.
• maintenance of a continuous supplyof sugars to the anthersand ovaries is essential to
maintain the energy requirements and viability of pollen grains and ovules.
• extending the durationof grainfill by delaying leaf senescence is a desirable trait that could
increase crop plant productivity under heat stress.
Abdelrahmanet al.,(2017)
43

44. Breeding for stay-green trait
• Stay-green phenotype and related traits has been reported to enhance grain yield especially
under post-anthesis drought conditions in wheat , sorghum,maize and rice.
• Stay-green is thus widely honouredas a droughtadaptation tool in cereals.
• Thus, this association could be used as a basis for selection of high-yielding stay-green
genotypes, especially for water-limitedenvironments.
• There are some reports for association of stay-green trait with bioticstresses like stemrotin
sorghum, spot blotch in spring wheat and stripe rust in wheat.
(Das et al., 2018)
44

45. • The improvement of stay-green phenotype is predicted to be much higher if information
about the presence of stay-greengenes/QTLs (quantitative trait loci) in the promising
genotypes can be gathered with the help of linked molecular markers.
• maize -fourteen QTLs (sg1.1.1, sg1.6.1, sg2.1.1, sg2.1.2, sg2.2.1, sg2.3.1, sg2.5.1, sg2.8.1 sg3.1.1,
sg3.2.1, sg3.5.1, sg3.9.1, sg4.1.1 and sg4.2.1) .
• sorghum-four QTLs (StgB, Stg1, Stg3 and Stg4)
• wheat -three QTLs (QSg.bhu-1A, QSg.bhu-3B and QSg.bhu-7D)
• rice - six QTLs (csfl2/tcs2, tcs4, tcs5, csfl6, csfl9/tcs9 and csfl12)
• barley -ten QTL (HGSQ, HSPFLQ1, HSPFLQ2, HSPFL1Q, HLAUGQ1, HLAUGQ2, WGSQ,
WGFL1Q1, WGFL1Q2, WLAUGQ) (Das et al., 2018)
45

46. • Wang et al. (2018) recently fine mapped a stay-green mutant in Brassica campestris L. ssp.
chinensis, which they termed “nye”.
• Genetic analysis revealed that the stay-green trait is controlled by a single recessive gene,
Brnye1.
• Brnye1gene was mapped on chromosome A03.
• Anotation of the identified gene was done based on B. rapaannotation database .
• identified Bra019346, a homolog of the Arabidopsis AtNYE1gene, as a potential candidate
gene responsible for the stay-greentrait
(Das et al., 2018)
46

47. Stay-green mutants and varieties identified in different plant species
Species Mutant or
variety
Type of stay-
green
Function
Arabidopsis thaliana nye1-1
ore10
ore11
ore1
ore4-1
ore7
ore9
ore12
dls1
Cosmetic
Cosmetic
Cosmetic
Functional
Functional
Functional
Functional
Functional
Functional
SGR
ND
ND
NAC transcription factor
Plastid ribosomal protein17
AT-hook transcription factor
F-box protein
Arabidopsis histidine kinase3
Arginyl tRNA:protein transferase
Capsicum annuum cl
Negral
Cosmetic
Cosmetic
SGR
ND Hortensteiner, 200947

48. Species Mutant or
variety
Type of stay-
green
Function
Citrus sinensis nan Cosmetic ND
Festuca pratensis Bf993 Cosmetic SGR
Festuca/Lolium
introgressions
Y Cosmetic SGR
Glycine max cytG
d1d2
Cosmetic
Cosmetic
ND
ND
Oryza sativa nyc1
sgr
SNU-SG1
Cosmetic
Cosmetic
Functional
Chlorophyll b reductase
SGR
ND
Phaseolus vulgaris Alamo Cosmetic ND
Hortensteiner, 200948

49. Species Mutant or
variety
Type of stay-
green
Function
Pisum sativum JI2775 Cosmetic SGR
Solanum
lycopersicon
gf Cosmetic SGR
Sorghum bicolor QL41 Cosmetic ND
Triticum aestivum XN901 Functional ND
Triticum durum 139; 142; 196;
504
Functional ND
Zea mays FS854 Functional ND
Hortensteiner, 200949

50. Ideotype of stay-green genotype
• spread and deep root system
• ability to uptake more silicon from soil
• slow rate of chlorophyll degradation as it leads to prolong the duration of leaf senescence
• genotypes should have more total plant leaf area
it is feasible to develop an ideal stay-greencultivar throughpyramiding all thesetraits from
potential sources using conventional or molecular breeding approaches
(Das et al., 2018)
50

51. CASE STUDY I
51

52. • The 14-3-3 proteins are a group of highly conservedregulatory proteins found in eukaryotic cells.
• They function as homo- or hetero-dimers and each monomer can bindto an interacting protein.
• In plants, 14-3-3 proteins were shown to regulate primary metabolism, ion transport, cellular
trafficking, enzyme activities and gene expression.
• overexpressionof 14-3-3 proteins in potato plants leads to increase in antioxidant activity by
45% and delayedleafsenescence, whereas reducedexpressionof 14-3-3 protein genes (by
antisense technology) in potato plants leads to early leaf senescence
52

53. • In Arabidopsis APX3 plays an important role in protecting plants under oxidative stress and
water-deficit conditions and AKR2 is involved in both disease resistance and antioxidation
metabolism.
• GF14λ interacts with several proteins that include ascorbate peroxidase 3 (APX3) and
ankyrin repeat-containing protein 2 (AKR2).
• overexpressionof GF14λ in cotton conferred a “staygreen” phenotype in transgenic cotton
plants.
53

54. Materials and methods
Vector construction and cotton transformation
• binary vector pCGN1578
• Intermediate Vector pRTL-2
• promoter CaMV 35S
• Selective marker - neomycin phosphotransferase gene
• Molecular analysis of transgenic plants
• Segregation of T1 plantsfor kanamycin resistant and transgene
• Water-deficit treatmentand gas-exchange analyses
54

55. Results
The “stay-green” phenotype of GF14λ- expressing cotton plants (#2 and #4) as
compared to wild type and segregated non-transgenic plants (#1 and #3).
55

56. 56

57. CASE STUDY II
57

58. • Sorghum(Sorghumbicolor(L.) Moench) is unique among the major cereals in that its grain is the
staple foodof the world’spoorest people, who have the lowest food security and who live primarily in
the semiarid tropics.
• Drought stress is a major constraint to crop production in semi-arid tropics.
• Improving drought tolerance of sorghum has been a challenge for plant breeders.
• Drought stress during grainfilling results in rapidpremature plantsenescence.
• Genotypes that can tolerate post-flowering drought stress maintain active photosynthesis when
subjected to water stress during the grain-filling period.
58

59. • Molecular markers, associated with stay-green, were identified and characterized in some
accessions, such as B35, E36-1, and SC56.
• three stay green QTLs, Stg1, Stg2 and Stg3, appear to be importantfor the expression of this trait.
• The transfer of the stay-green trait into elite lines is expected to be broadly beneficial for increasing
yield in a wide range of environments.
59

60. Materials and methods
• Plant material
• 46 BC2F4 stay-green introgression lines (BILs) from a cross between ‘Tabat’ × B35 by marker-
assisted backcrossing (MAB).
• Rain-FedExperiments
• DataCollection
• percent of greenness (%G) at both grain filling (GF) and maturity (M).
• Statistical Analysis
60

61. Results
• The introgression of the stay-green QTLs enhanced post-flowering drought tolerance and
increased the GY and biomass of Tabat.
• Under drought conditions, some BILs had GY and biomass higher than ‘Tabat’.
• Stg1 was the best QTL in term of GY.
• The study provided evidence that MAB withstay-green QTLs can enhance sorghumyield
under post-flowering drought.
61

62. Case Study III
62

63. • Stover fodder traits are important since farmers rejected new cultivars that were improved
only for grain yield with no regard to stover traits.
• In India sorghum stover is particularly important as dry season fodder for livestock especially
during post rainy season.
• key stover fodder quality traits were significantly higher in Rabi compared to Kharif
sorghum stover, the former having a mean digestibility of 51.7% compared to46.5% in
Kharif stover.
63

64. • Rabi sorghum stover commands higher prices than Kharif stover because of stover fodder
quality and seasonality.
• Introgression of stay-green genes may offer opportunities to improve stover fodder quality
while maintaining, and even improving, agronomic yield traits, especially under the water –
limiting conditions.
64

65. • Geneticmaterial
• introgression lines containing staygreen QTLs from B-35 donor parent in two genetic backgrounds: S-
35 andR-16.
• Staygreen QTL introgression lines in S-35 background con-tained one of the six staygreen QTLs (Stg1,
Stg2, Stg3, Stg4, StgA and StgB) from donor B-35 - BTx642.
• R-16 backgrounds contained one of the four staygreen QTLs (Stg1, Stg3, Stg4 and StgB) from donor B-
35.
• Fieldexperiments Trials
• Experimental trials were conducted in the post rainy seasons 2008–2009 and2009–2010 at ICRISAT
headquarters
• Stover analysis
• Stover nitrogen (N), neutral (NDF) and acid detergent fiber (ADF), acid detergent lignin (ADL) and in
vitro organic matter digestibility (IVOMD) .
Materials and Methods
65

66. Result
• The effect of QTL on selected stover fodder quality traits was background dependent.
• In S-35 one stay-green QTL (StgB) increased stover IVOMD and grain and stover yield while
no concomitant trait improvement was observed in background R-16.
• It is concluded that stay=green QTL can contribute to improving stover quality and grain
and stover yield in a background-dependent manner.
66

67. Result
67

68. CONCLUSION
68

69. Reference
Thomas, H., & Ougham, H. (2014). The stay-green trait. Journal of Experimental Botany, 65(14),
3889-3900.
Abdelrahman, M., El-Sayed, M., Jogaiah, S., Burritt, D. J., & Tran, L. S. P. (2017). The “STAY-GREEN”
trait and phytohormone signaling networks in plants under heat stress. Plant cell reports, 36(7),
1009-1025.
Jagadish, K. S., Kishor, K., Polavarapu, B., Bahuguna, R. N., von Wirén, N., & Sreenivasulu, N. (2015).
Staying alive or going to die during terminal senescence—an enigma surrounding yield
stability. Frontiersin plant science, 6, 1070.
Hörtensteiner, S. (2009). Stay-green regulates chlorophyll and chlorophyll-binding protein
degradation during senescence. Trends in plant science, 14(3), 155-162.
Kusaba, M., Tanaka, A., & Tanaka, R. (2013). Stay-green plants: what do they tell us about the
molecular mechanism of leaf senescence. Photosynthesis Research, 117(1-3), 221-234.
69

70. Reference
Gregersen, P. L., Culetic, A., Boschian, L., & Krupinska, K. (2013). Plant senescence and crop
productivity. Plant molecular biology, 82(6), 603-622.
Schippers, J. H., Schmidt, R., Wagstaff, C., & Jing, H. C. (2015). Living to die and dying to
live: the survival strategy behind leaf senescence. Plant Physiology, 169(2), 914-930.
Thomas, H., & Howarth, C. J. (2000). Five ways to stay green. Journal of experimental
botany, 51(suppl_1), 329-337.
Yan, J., He, C., Wang, J., Mao, Z., Holaday, S. A., Allen, R. D., & Zhang, H. (2004).
Overexpression of the Arabidopsis 14-3-3 protein GF14λ in cotton leads to a “stay-green”
phenotype and improves stress tolerance under moderate drought conditions. Plant and Cell
Physiology, 45(8), 1007-1014.
70

71. • Christopher, J. T., Christopher, M. J., Borrell, A. K., Fletcher, S., & Chenu, K. (2016). Stay-
green traits to improve wheat adaptation in well-watered and water-limited
environments. Journal of Experimental Botany, 67(17), 5159-5172.
• Kamal, N. M., Gorafi, Y. S. A., & Ghanim, A. M. A. (2017). Performance of Sorghum Stay-
green Introgression Lines Under Post-Flowering Drought. International Journal of Plant
Research, 7(3), 65-74.
Reference
71

72. THANK YOU
The future's bright, The future's ... green
72