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This book presents a comprehensive view of the impact of various abiotic stresses on plants and their response to them. I would like to express my sincere thanks to Devaiahu Kambiranda for his help in editing some of the chapters.

Enhancing Phytoremediation Efficiency in Response to Environmental Pollution Stress

  • Introduction
  • Phytoremediation
    • Phytoextraction and phytomining
    • Rhizofiltration
    • Phytostabilization
    • Phytodegradation and rhizosphere-enhanced degradation
    • Phytovolatization
    • Phytorestoration
  • Plant response to abiotic stresses
  • Enhancing phytoremediation efficiency
    • Plant-bacteria symbiosis
    • Plant-fungi symbiosis
    • Transgenic plants
  • Conclusion
  • Acknowledgment
  • References

Bacteria can produce osmolytes, such as glycine betaine, act synergistically with plant osmolytes, accelerating osmotic adjustment (Dimkpa et al., 2009). Iron-chelating siderophore complexes can be taken up by the host plant, resulting in higher fitness (Dimkpa et al., 2009).

Table 1. Genes involved in plant genetic engineering for phytoremediation of heavy metals  (Hsieh et al., 2009; Karenlampi et al., 2000; Kotrba et al., 2009; Kolodyazhnaya et al., 2009)
Table 1. Genes involved in plant genetic engineering for phytoremediation of heavy metals (Hsieh et al., 2009; Karenlampi et al., 2000; Kotrba et al., 2009; Kolodyazhnaya et al., 2009)

Morphophysiological Investigations in Some Dominant Alien Invasive Weeds

Ecological impacts of invasive plants on the environment

Scope of allelopathy

Allelobiogenesis - concept and mechanism

  • Plant invasions and encroachments

As stated by Li et al. 2009), the invasion of exotic weeds is mainly due to their easier establishment and faster growth under diverse environmental conditions. The new weapon hypothesis (Callaway and Ridenour 2004), biotic resistance hypothesis (Maron and Vilà 2001), and the genetic drift hypothesis (DeWalt et al. 2004) also explain the mechanism of invasion.

Diagram 1. Mechanism of action and physiological effects  2.1 Allelopathic interactions between plants
Diagram 1. Mechanism of action and physiological effects 2.1 Allelopathic interactions between plants

Compilation of updated work

  • Invasion success of weeds
  • Allelochemicals in invasive and native weed species

Asteraceae plants with their leachates, extracts and residues of various plant parts are known for their allelopathic activity due to their allelochemicals such as phenolic acids and terpenoids (Chon et al. 2003). Many researchers such as Ghayal et al. 2009) have given utmost importance to the identification of allelochemicals, ecochemicals and novel bioactive compounds that are the secondary metabolites found in their leachate products, extracts and residues.

Diagram 2. Different pathways of synthesis of allelochemicals
Diagram 2. Different pathways of synthesis of allelochemicals

About the study area

  • Weed floristic of study area
  • Invasion components
  • Secrets of invasion / encroachment and aggressiveness
  • Morphological specifications of invasive and native weeds
  • Light harvesting components in invasive and native weeds
  • Carbon assimilation rate of invasive and native weeds
  • Biochemical nature invasive and native weeds
  • ROS scavenging mechanism of invasive and native weeds
  • Antioxidant enzymes in invasive and native weeds

The least reproductive capacity was reported in Boerhaavia (Table 3b). b) Reproductive characteristics of invasive and native weeds. The remaining invasive and native weeds were in an intermediate state in terms of photosynthetic pigment content.

Table 1. (d) Weed-weed interactions at site IV in Pune university campus
Table 1. (d) Weed-weed interactions at site IV in Pune university campus
  • Allelobiogenesis of invasive weeds
    • GC-MS study
    • IR, NMR, and MASS spectra studies
  • Conclusions
  • Future research
  • References

Allelochemicals such as terpenes, steroids, flavonoids, alkaloids, etc., have a great influence on the physiology of host plants, all the way from the gene to the organismal level, e.g. monoterpenes, which are the main constituents of essential oils from many higher plants, interfere with basic biological processes such as DNA replication, respiration, enzyme activities, seed germination and plant growth. The allelopathic potential exhibited by both weeds may be due to the different types of allelochemicals that exist in them.

Alteration of Abiotic Stress Responsive Genes in Polygonum minus Roots

Elicitation

  • The concept of elicitation
  • Case study: Elicitation of Polygonum minus roots with JA
    • Phytochemical analysis of P. minus roots
    • The effect of JA elicitation on the production of volatile compounds in P. minus roots

These ROS could trigger the formation of bioactive fatty acid derivatives in plants (Apostol et al. 1989). It is also known as a molecule involved in the signal transduction pathway leading to the activation of plant defenses against attacks by pathogens, insects and herbivores (Menke et al. 1999). For example, cell cultures of Hypericum perforatum (St. John's wort) showed a significant increase in hypericin production after treatment with JA (Walker et al. 2002).

Since most of the secondary metabolites induced by elicitor are present de novo in plant cells (Pare & Tumlinson 1997) and involved some enzyme activity induction (Bouwmeester et al. 1999; Degenhardt & Gershenzon 2000), the production of volatile compounds induced by JA in kesum roots will reflect the enzyme activities that catalyzed the biosynthesis of those compounds.

Table 1. Classification of elicitors according to their nature or origin  2.2 JA biosynthesis and its roles in plant secondary metabolism
Table 1. Classification of elicitors according to their nature or origin 2.2 JA biosynthesis and its roles in plant secondary metabolism
  • Discovery of unknown and novel cDNA sequences discovered during JA elicitation
    • Computational analysis of unknown genes
    • Protein characterization by physicochemical properties
    • Similarity search
  • Effect of JA elicitation on gene expression
  • Correlation study between phytochemistry profiling and transcriptomic dataset .1 Genes involved in aromatic compounds production
    • Genes related to abiotic stress
    • Transcription factor activated by JA

This result implies that many different stressors will lead to the same gene expression (Sandermann et al. 1998). Moreover, MSI1 has also been proven to function in signal transduction mechanism (Zheng et al. 2004). Alcohol dehydrogenase (ADH, EC 1.1.1.1), identified in this study, could be involved in the formation of phenylpropanoids, another group of volatile aromatic compounds (Devitt et al. 2006).

In fact, it is the main ingredient in a number of commercial herbicides (Andrews et al. 2005).

Fig. 4. Reverse Northern analysis showing differential screening for putative cDNA clones  altered by JA
Fig. 4. Reverse Northern analysis showing differential screening for putative cDNA clones altered by JA

Conclusion

The functions of these proteins have been demonstrated in Arabidopsis and they may act as transcription factors in genes expressed in response to JA treatment. While these proteins all play the same role in the regulation of JA, they also regulate species-specific secondary metabolite pathways (Pauwels et al. 2009). These proteins need to be characterized and investigated for the mechanism that drives secondary metabolite production in response to JA.

Acknowledgement

Expression of the BnmNAP subfamily of napin genes coincides with the induction of Brassica microspore embryogenesis. Production of the phenolic flavor compounds by cultured cells and tissues of Vanilla planifolia species. Involvement of the octadecanoid pathway and protein phosphorylation in fungal elicitor-induced expression of terpenoid indole alkaloid biosynthetic genes in Catharanthus roseus.

Expression of the peroxidase gene promoter (Shpx6b) from Stylosanthes humulis in transgenic plants during insect attack.

Transcriptomics of Sugarcane Osmoprotectants Under Drought

  • Drought: Understanding the problem
  • Sugarcane and drought: Current outlook and use of science in search of solutions
  • Drought and osmoprotectants in plants
    • Glycine betaine
    • Proline
    • Myo-inositol
    • Trehalose
  • SuperSAGE: Looking for osmoprotectants in sugarcane
    • Betaine aldehyde dehydrogenase (BADH)

Some of them use the association of SuperSAGE with a high-throughput sequencing platform (HT-SuperSAGE; Matsumura et al., 2010). Economic losses related to water availability reached approximately one billion dollars in 2009, in the United States alone (Anderson et al., 2009). At least three different pathways for the biological synthesis of trehalose have been reported (Elbein et al., 2003).

Although trehalose is widely distributed in nature (including prokaryotes and eukaryotes), this sugar has been isolated from a few plant species, and is identified in ripening fruits of species in the Apiacea family, in the leaves of Selaginella lepidophylla and its relatives (Goddijn & van Dun, 1999) and in Arabidopsis thaliana (Wingler et al., 2002).

  • Delta(1)-pyrroline-5-carboxylate synthetase (P5CS)
  • Delta(1)-pyrroline-5-carboxylate reductase (P5CR)
  • Myo-inositol 1-phosphate synthase (MIPS)
  • Trehalose-6-phosphate synthase (TPS)
  • Trehalose-phosphatase protein (TPP)
  • Concluding remarks
  • Acknowledgments

Proceedings of the National Academy of Sciences of the United States of America, (November 2005), Vol. 1980) Regulation of structural gene expression in tobacco. Journal of Plant Growth Regulation, Vol. 2010) Plant antimicrobial peptides: a SuperSAGE transcriptional profiling review and a. International Journal of Food Microbiology, Vol. 2007) Increasing glycinebetaine synthesis improves drought tolerance in cotton. 2004) An EST survey of the sugarcane transcriptome.

Theoretical and Applied Genetics, Vol. 2007) Glycinebetaine application alleviates negative effects of drought stress in tobacco.

Table 2. BlastN results of SuperSAGE osmoprotectants-related tags from sugarcane roots  under hydric deficif against cDNAs of Sorghum bicolor (Phytozome database)
Table 2. BlastN results of SuperSAGE osmoprotectants-related tags from sugarcane roots under hydric deficif against cDNAs of Sorghum bicolor (Phytozome database)

Effect of UV Light on Secondary Metabolite Biosynthesis in Plant Cell Cultures Elicited

Effect of UV light exposure, CDs and MJ on the production of trans- resveratrol

The production of trans-resveratrol in cell cultures of Vitis sp has been analyzed by several groups (Kiselev 2011 and see here). Effect of UV-C light exposure on trans-resveratrol production in Monastrell cell cultures induced in the presence of CDs individually or in combination with MJ. However, when Monastrell cell cultures were co-extracted with CD and MJ and exposed to UV-A light (Fig. 5), the maximum level of trans-resveratrol was found at long exposures (30 min mg/g FW, 90 min mg/ g FW) although no significant differences were found between CD+MJ-treated cells exposed to UV-A light at these long times and unexposed cells treated with the same elicitor chemicals mg/g FW).

The results suggested that the effect of UV light on trans-resveratrol production depended not only on the exposure time (short or long) and the type of UV light (C or A), but also on the presence of one or two chemical inducers (CDs and/or or MJ).

Fig. 4. Effect of UV-C light exposure on the production of trans-resveratrol in Monastrell cell  cultures elicited in presence of CDs individually or in combination with MJ
Fig. 4. Effect of UV-C light exposure on the production of trans-resveratrol in Monastrell cell cultures elicited in presence of CDs individually or in combination with MJ

Effect of UV light exposure, CDs and MJ on the production of indole alkaloids

Effect of different exposure times to UV-C light on extracellular accumulation of ajmalicin and catharanthin in cell cultures of C. Effect of different exposure times to UV-C light on extracellular accumulation of phytosterols in cell cultures of D. Effect of different UV-A light ( 360 nm , 10μW/cm2) exposure times on extracellular accumulation of phytosterols in cell cultures of D.

However, the effect of UV light on the production of these secondary metabolites depends not only on the exposure time (short or long) and the type of UV light (C or A), but also on the presence of one (CD) or two chemicals. elicitors (CD and MJ).

Fig. 6. Effect of different UV-C light exposure times on extracellular accumulation of  ajmalicine and catharanthine in cell cultures of C
Fig. 6. Effect of different UV-C light exposure times on extracellular accumulation of ajmalicine and catharanthine in cell cultures of C

Acknowledgments

Enhancement of ajmalicin production in Catharanthus roseus cell cultures by methyl jasmonate depends on the elicitation time and dose. Induction of sesquiterpenes, phytosterols and extracellular pathogenesis-related proteins in challenged cell cultures of Capsicum annuum. Enhanced catharanthine production in Catharanthus roseus cell cultures by combined elicitor treatment in shake flasks and bioreactors.

Production and metabolic engineering of terpenoid indole alkaloids in cell cultures of the medicinal plant Catharanthus roseus (L.) G.

Drought Tolerance and Stress Hormones

From Model Organisms to Forage Crops

Phytohormones and drought stress

  • Abscisic acid (ABA)
  • Salicylic acid (SA)
  • Jasmonic acid (JA)

Therefore, plants control their developmental programs and stress responses by modulating endogenous ABA levels (Schwartz et al., 2003). The most common oxidative pathway is initiated by oxidation of the 8'-hydroxy ABA (8'-OH ABA), which can reversibly cyclize to phase acid (PA) (Zaharia et al., 2005). The increase in ABA levels also correlated with a marked decrease in plant height and leaf senescence (Kannangara et al., 1983).

In Panicum virgatum, ROS has been linked to ABA signaling during germination (Sarath et al., 2007).

Fig. 1. A. Content of ABA in leaves of Panicum virgatum cv. Greenville grown under  drought (Drought) and after 12 and 24 h of re-watering (RW 12 h and RW 24 h)
Fig. 1. A. Content of ABA in leaves of Panicum virgatum cv. Greenville grown under drought (Drought) and after 12 and 24 h of re-watering (RW 12 h and RW 24 h)

ABA, SA, JA and cross talk between each other

Exogenous application of JA or Me-JA increased the antioxidative ability of plants under water stress (Wang, 1999; Bandurska et al., 2003). Taken together, these results suggest that exogenous SA and ABA can lead to enhancement of thermotolerance (Liu et al., 2006). Nevertheless, ABA and JA would be involved in different phases of the response and drive an acclimation process during growth through an extensive genetic reprogramming to finally reach a new homeostasis (Harb et al., 2010).

The crosstalk between JA and ABA may occur as they use a similar cascade of events to stimulate some responses (Harb et al., 2010; Fujita et al., 2006).

Fig. 5. Model of hormonal response of Panicum virgatum cv. Greenville grown under  drought (Drought) and after 12 and 24 h of re-watering (RW 12 h and RW 24 h)
Fig. 5. Model of hormonal response of Panicum virgatum cv. Greenville grown under drought (Drought) and after 12 and 24 h of re-watering (RW 12 h and RW 24 h)

Conclusions and perspectives

Or it could reorganize endogenous levels of plant hormones to achieve a new homeostasis when adapting to new environmental conditions (Fujita et al., 2006). Overall, this new hormonal status suggests an interplay between SA-JA-ABA in water stress responses in P. (i.e., maize, sorghum, rice, and brachypodium), representing the three most economically important subfamilies of grasses, were analyzed. In the same line, the first pooid grass, Brachypodium distachyon (Brachypodium), was recently fully sequenced and proposed as a new model that can contribute to the improvement of grass production (Bevan et al., 2010).

In the near future, the combination of these new technologies will help unravel the complex interactions between plant hormones in forage crops.

Effect of salicylic acid on growth, photosynthesis and carbohydrate metabolism in salt-stressed maize plants. Ozone-induced cell death occurs via two different mechanisms in Arabidopsis: the role of salicylic acid. The role of the hormonal system in the manifestation of the growth-promoting and anti-stress effects of salicylic acid.

Effects of exogenous salicylic acid on manganese toxicity, element content and antioxidant system in cucumber.

Iron Stress in Citrus

  • Iron chlorosis in plants
  • Effects of iron chlorosis in citrus
  • Screening citrus rootstocks to iron chlorosis
  • Future research and conclusion
  • Acknowledgment

The problem of iron chlorosis is widespread because limestone soils cover approximately 30% of the land area (Chen et al. 1982). The reduction of the thylakoid membrane is associated with reduced concentrations of photosynthetic pigments (chlorophylls a and b and carotenoids) in the leaves of affected plants (Morales et al.). The pH of the root cytosol and vacuole increases as a result of the apoplast acidification that occurs. in response to Fe deficiency (Espen et al., 2000).

Characterization of the tolerance to iron chlorosis in different peach rootstocks grown in nutrient solution.

Fig. 1. Control and chlorotic leaves of citrange Carrizo.
Fig. 1. Control and chlorotic leaves of citrange Carrizo.

Response, Tolerance and Adaptation to Abiotic Stress of Olive, Grapevine and Chestnut in the

Morpho-anatomical, physiological, and biochemical response and adaption

  • Olive capacity to withstand arid environments
  • Vine’s response, tolerance and adaptation to abiotic stress
    • Abiotic stress response
    • Tolerance and adaptation

During periods of water stress, the olive tree typically experiences reductions in transpiration, stomatal conductance, and net photosynthesis (Giorio et al., 1999). Mannitol and glucose play a major role in the osmotic regulation of olive leaves (Cataldi et al., 2000). The concentration of ABA, coming from roots to leaves, is directly implicated in this behavior (Correia et al., 1995).

In fact, Flexas et al. 1999) found that grapevines in their natural environment and under water stress developed only a few signs of reduced photochemical activity.

Fig. 1. Olive protections at leaf level against water loss and excessive irradiance. (A)  Paraheliotropic movement under water stress; (B) Dense packing of the mesophyll layers  and thick cuticle and epicuticular wax layers (optical micrograph); (C) Dense
Fig. 1. Olive protections at leaf level against water loss and excessive irradiance. (A) Paraheliotropic movement under water stress; (B) Dense packing of the mesophyll layers and thick cuticle and epicuticular wax layers (optical micrograph); (C) Dense

Limitations of European chestnut growth at low latitudes

1800 m in the Caucasus Mountains, the former altitudes correspond to the old orchards and the highest altitudes to the newest plantations (Gomes-Laranjo et al., 2005; Pereira-Lorenzo et al., 2010). For superior Portuguese varieties, half the rate of photosynthesis (A50) is found when the temperature reaches 11ºC (T50m) and 38ºC (T50M), which is the optimal value around 24ºC (Gomes-Laranjo et al., 2007). A significant genetic variation between North and South Iberian ecotypes has also been confirmed (Fernández-López et al., 2005).

Determination of photosynthetic pigment content (n=10), fatty acid composition (n=3) and malonic aldehyde (n=3) in chestnut (var. Judia) chloroplast (Gomes-Laranjo et al., 2005) isolated from leaves collected in the altitude range between 450 and 1050 m a.s.l. The altitude and therefore the air temperature also affects the thylakoid fatty acid composition (Table 1).

Fig. 2. Threshold temperature (left) and radiation (right) for photosynthesis rates in chestnut  leaves
Fig. 2. Threshold temperature (left) and radiation (right) for photosynthesis rates in chestnut leaves

Abiotic stress signalling 1 The role of abscisic acid (ABA)

Figure

Diagram 1. Mechanism of action and physiological effects  2.1 Allelopathic interactions between plants
Table 1. (d) Weed-weed interactions at site IV in Pune university campus
Table 2. Morphological features of invasive and native weeds  4.5 Reproductive capabilities of invasive and native weeds
Fig. 2. Total sugars and starch contents in the invasive and native weeds
+7

References

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