Does overhead irrigation with salt affect growth, yield, and phenolic content of lentil plants?

Overhead irrigation of lentil plants with salt (100 mM NaCl) did not have any significant impact on plant growth, while chlorophyll content and chlorophyll fluorescence parameter Fv/Fm were affected. Under such poor irrigation water quality, the malondialdehyde content in leaves was increased due to the lipid peroxidation of membranes. In seeds, the total phenolic content (TPC) was correlated to their total antioxidant capacity (TAC). High performance liquid chromatography-mass spectrometry (HPLC-MS) detection showed that flavonoids (catechin, epicatechin, rutin, p-coumaric acid, quercetin, kaempferol, gallic acid and resveratrol) appear to be the compounds with the greatest influence on the TAC values. Catechin is the most abundant phenolic compound in lentil seeds. Overhead irrigation with salt reduced the concentration of almost all phenolic compounds analyzed from lentil seed extracts

Does overhead irrigation with salt affect growth, yield, and phenolic content of lentil plants?

Overhead irrigation of lentil plants with salt (100 mM NaCl) did not have any significant impact on plant growth, while chlorophyll content and chlorophyll fluorescence parameter F-v/F-m were affected. Under such poor irrigation water quality, the malondialdehyde content in leaves was increased due to the lipid peroxidation of membranes. In seeds, the total phenolic content (TPC) was correlated to their total antioxidant capacity (TAC). High performance liquid chromatography-mass spectrometry (HPLC-MS) detection showed that flavonoids (catechin, epicatechin, rutin, p-coumaric acid, quercetin, kaempferol, gallic acid and resveratrol) appear to be the compounds with the greatest influence on the TAC values. Catechin is the most abundant phenolic compound in lentil seeds. Overhead irrigation with salt reduced the concentration of almost all phenolic compounds analyzed from lentil seed extracts

The effect of water stress and salinity on growth and physiology of tomato (Lycopersicon esculentum Mil.)

Carotenoids like lycopene are important pigments found in photosynthetic pigment-protein complexes in plants. They are responsible for the bright colors of fruits and vegetables and perform various functions in photosynthesis. Our research has shown that the application of moderate salt stress on tomato plants can enhance lycopene and potentially other antioxidant concentrations in fruits. The increase in lycopene in response to salt stress in the tomato fruits varied from 20% to 80%. Although the specific biological mechanisms involved in increasing fruit lycopene deposition has not been clearly elucidated, evidence suggests that increasing antioxidant concentrations is a primary physiological response of the plant to salt stress. Additionally drought stress during cultivation increased the antioxidant capacity of tomato fruit while maintaining the lycopene concentration. In addition, the effects of silicium were investigated, added to the nutrient solution either at low concentration or at an increased concentration. The present study clearly indicates that an enhanced silicium supply to tomato increases markedly the lycopene contents, irrespective of the salinity status in the tomato fruit

Study of effect of Al in two inbred lines of maize (Zea mays L.) with different tolerance in Al

The aim of this dissertation was to study the effect of Αl on Zea mays plants. More specificly were investigated at a morphological, cytological and physiological level two maize inbred lines with different Al tolerance. Seed germination experiments indicated that low concentrations οf Al did not influence substantially the germination process either of the two inbred lines. On the contrary, the high concentrations of Al had a negative affect upon (particularly in the sensitive inbred line) the seed germination and the indicator of tolerance elongation of root of plants. Concurrently at the biochemical level the concentration of Al in the nutritious solution was positively correlated with the concentration of Al, proline, the carbohydrates, the lipid peroxidation (malondialdeyde) H2O2, in the root and in the shoot-leaves. However the tendency of the distribution of all the parameters in the tissues of the tolerant and sensitive inbred line appeared to be different. Specifically the tolerant maize line seem to endure low level of lipid peroxidation and to accumulate higher levels of carbohydrates and proline which are related to the osmoregulation and the membrane stabilization. These observations suggest an efficient metabolism system in the tolerant maize line VA-22 during Al stress. Nevertheless, in both of the two inbred lines, the accumulation of Al in the roots appeared to be higher compared to the transport of the metal in the upper parts of plants. As far as the toxic effect of high concentrations of Al is concerned a negative correlation with the elements K, Mg, Fe and Mn became apparent. Generally, low concentrations of Al did not influence the uptake and transport of nutritious elements from roots to shoots-leaves, in the tolerant inbred line. Likewise, the tolerant line retained larger concentrations of Ca2+, Mg2+ and K+, measured in roots and in shootsleaves, compared to the sensitive inbred line A4/67. From the cytological results it was realised that the concentration of 60 mM Al for 24 hours did not cause serious damage in the root. In particular, it was observed increase of vacuoles (vacuolization) and shrink of cellular membrane. In regard to the the electrophoretic studies, it appeared that the concentration of 240 mM Al on the third day caused the appearance of one of low molecular weight DNase only in the ensitive inbred line. Also it appeared one low molecular weight DNase in the concentration of 360 mM Al on the fifth day and only in the sensitive inbred line. Serious differences were observed between the two inbred lines after 24, 48 and 72 hours of exposure to aluminium. More specific in the tolerant inbred line there was an increase in the activity of antioxidant enzymes (there were found increased SOD and POX activity in the roots, contrary to the sensitive inbred line where a reduction in the activity of SOD and POX enzymes was observed). Μοre specificly the anionic POD isoforms profiles and the SOD isoforms profiles showed that in the Al-tolerant maize plants the anionic POD isoforms A2 and A4 and the SOD isoforms SOD1 and SOD2 were induced by increased Al-stress. It seemed that in the Al tolerant maize line, the anionic POD isoforms A2 and A4 and the SOD isoforms SOD1 and SOD2 were required for adaptation as the oxidant level increased by the increased Al stress. The results of the present study suggest that Al toxicity may be mediated by oxidative stress, and that the better protection of the Al tolerant maize roots from Al-induced oxidative damage results, at least partially, from the increased activity of their antioxidative system. Thus, the ability of tolerant inbred line to increase the antioxidant activity of the system with aim to limits the cellular damage can be a mechanism that leads to the Al tolerance. Εlectrophoretic analysis of phosphatases and esterases isoforms had different electrophoretic pattern in both enzymes. In the tolerant inbred line appeared six esterases isoforms (EST1, EST4, EST5, EST6, EST7, EST8) and four phosphatases isoforms (ACP1, ACP2, ACP5, ACP6) while in the sensitive inbred line appeared five esterases isoforms (EST4, EST5, EST6, EST7, EST8) and five phosphatases isoforms (ACP3, ACP4, ACP6, ACP7, ACP8). Specificly the activity of phosphatases and esterases isoforms in the tolerant inbred line increased especially in the highest Αl concentration (480 μΜ), but on the contrary in the sensitive line the activity of those enzymes decreased in this concentration. ...........................................................Σκοπός αυτής της διατριβής ήταν η μελέτη της συμπεριφοράς του καλαμποκιού (Zea mays L.) στην επίδραση του Al. Πιο συγκεκριμένα διερευνήθηκε η επίδραση του Al σε μορφολογικό, κυτολογικό, βιοχημικό και φυσιολογικό επίπεδο σε δύο καθαρές σειρές καλαμποκιού (VA-22, A4/67), με διαφορετική ανθεκτικότητα ως προς σε αυτό. Από τα πειράματα της φυτρωτικότητας των σπερμάτων διαπιστώθηκε ότι σε χαμηλές συγκεντρώσεις Αl δεν επηρεάστηκε ουσιαστικά η φύτρωσή τους σε καμία από τις δύο καθαρές σειρές. Αντίθετα οι υψηλές συγκεντρώσεις Αl στην ευαίσθητη καθαρή σειρά, επέδρασαν αρνητικά ιδιαίτερα στη φυτρωτικότητα των σπερμάτων και στο επί τις % μήκος της ρίζας (δείκτη ανθεκτικότητας) των φυτών. Παράλληλα, σε βιοχημικό επίπεδο η συγκέντρωση του Αl στο θρεπτικό διάλυμα συσχετίστηκε θετικά με τη συγκέντρωση των υδατανθράκων της προλίνης, της υπεροξείδωσης των λιπιδίων (μηλονυλο-διαλδεύδης) και τoυ H2O2 στη ρίζα και στο βλαστό. Διαφορετική όμως εμφανίστηκε η τάση κατανομής όλων των παραπάνω παραμέτρων στους ιστούς της ανθεκτικής και της ευαίσθητης καθαρής σειράς. Η ανθεκτική καθαρή σειρά διατήρησε χαμηλό το επίπεδο της υπεροξείδωσης των λιπιδίων με παράλληλη συσσώρευση υψηλότερων επιπέδων υδατανθράκων και προλίνης, οι οποίοι σχετίζονται με την οσμωρυθμιστικότητα και την σταθεροποίηση των μεμβρανών. Όλες αυτές οι παρατηρήσεις δείχνουν ένα πολύ αποδοτικό μεταβολικό σύστημα στην ανθεκτική καθαρή σειρά VA-22 κατά τη διάρκεια της καταπόνησης με Al. Παρόλα αυτά, και στις δύο καθαρές σειρές, η συσσώρευση του Αl ήταν αυξημένη στις ρίζες και σχετικά περιορισμένη η μεταφορά του στο υπέργειο τμήμα των φυτών. Σε ότι αναφορά την τοξική επίδραση των υψηλών συγκεντρώσεων του Αl εμφανίστηκε αρνητική συσχέτιση με τα στοιχεία K+, Ca2+, Mg2+, Fe2+ και Mn2+. Γενικά μικρές συγκεντρώσεις Αl δεν επηρέασαν την πρόσληψη και μεταφορά των θρεπτικών στοιχείων από τη ρίζα στο βλαστό-φύλλα, στην ανθεκτική καθαρή σειρά. Από τα κυτολογικά αποτελέσματα διαπιστώθηκε ότι συγκέντρωση 60 μΜ Αl για 24 ώρες δεν προκάλεσε σοβαρές βλάβες στη ρίζα. Συγκεκριμένα παρατηρήθηκε αύξηση του αριθμού των χυμοτοπίων στη ρίζα, πάχυνση και έντονο χρωματισμό των κυτταρικών τοιχωμάτων της εξωδερμίδας και του πρωτογενούς φλοιού. Με βάση την ηλεκτροφορητική ανάλυση των ισομορφών των νουκλεολυτικών ενζύμων στη ρίζα, βρέθηκε ότι μετά από την επίδραση Αl συγκέντρωσης 240 μΜ για τρεις ημέρες, προκλήθηκε η εμφάνιση μιας χαμηλού μοριακού βάρους DNάσης μόνο στην ευαίσθητη καθαρή σειρά. Αντίστοιχα παρουσιάστηκε στο βλαστό μετά από την επίδραση Αl συγκέντρωσης 360 μΜ για πέντε ημέρες, μια επίσης χαμηλού μοριακού βάρους DNάση και μόνο στην ευαίσθητη καθαρή σειρά. Σοβαρές διαφορές εξάλλου, παρατηρήθηκαν ανάμεσα στις δύο καθαρές σειρές μετά από 24, 48 και 72 ώρες έκθεσης στο Al. Συγκεκριμένα στην ανθεκτική καθαρή σειρά είχαμε αύξηση της δραστικότητας των αντιοξειδωτικών ενζύμων SOD και POD στις ρίζες ενώ αντίθετα στην ευαίσθητη καθαρή σειρά είχαμε μείωση της δραστικότητάς τους. Συγκεκριμένα το ηλεκτροφορητικό πρότυπο των ανιονικών ισομορφών των POD (ισομορφές A2 και A4) καθώς και το πρότυπο των ισομορφών των SOD (ισομορφές SOD1 και SOD2) έδειξε ότι στην ανθεκτική καθαρή σειρά, η δράση των ενζύμων είναι ανάλογη με την καταπόνηση με Al. Φαίνεται ότι στην ανθεκτική καθαρή σειρά, oι ανιονικές POD ισομορφές A2 και A4 και οι SOD ισομορφές SOD1 και SOD2 απαιτούνται για την προσαρμογή καθώς το οξειδωτικό επίπεδο αυξάνεται με την αύξηση της καταπόνησης με Al. Σύμφωνα με τις παραπάνω παρατηρήσεις προκύπτει ότι η καλύτερη προστασία των ριζών της ανθεκτικής καθαρής σειράς από την πρόκληση οξειδωτικών καταστροφών, λόγω της τοξικότητας του Al, τουλάχιστον εν μέρει, προέρχεται από την αυξημένη δραστικότητα των αντιοξειδωτικών ενζύμων ( POD και SOD). Έτσι η ικανότητα της αύξησης της αντιοξειδωτικής δράσης του συστήματος στην ανθεκτική καθαρή σειρά, με σκοπό τον περιορισμό των κυτταρικών βλαβών μπορεί να είναι ένας μηχανισμός που οδηγεί στην ανθεκτικότητα στο Αl. Η ηλεκτροφορητική ανάλυση των ισομορφών τόσο των φωσφατασών όσο και των εστερασών παρουσίασε διαφορετικό ηλεκτροφορητικό πρότυπο και στα δύο αυτά ένζυμα. ...................................................................................

Effect of Lead and Copper on Photosynthetic Apparatus in Citrus (<i>Citrus aurantium</i> L.) Plants. The Role of Antioxidants in Oxidative Damage as a Response to Heavy Metal Stress

Photosynthetic changes and antioxidant activity to oxidative stress were evaluated in sour orange (Citrus aurantium L.) leaves subjected to lead (Pb), copper (Cu) and also Pb + Cu toxicity treatments, in order to elucidate the mechanisms involved in heavy metal tolerance. The simultaneous effect of Pb− and Cu on growth, concentration of malondialdehyde (MDA), hydrogen peroxide (H2O2), chlorophylls, flavonoids, carotenoids, phenolics, chlorophyll fluorescence and photosynthetic parameters were examined in leaves of Citrus aurantium L. plants. Exogenous application of Pb and Cu resulted in an increase in leaf H2O2 and lipid peroxidation (MDA). Toxicity symptoms of both Pb and Cu treated plants were stunted growth and decreased pigments concentration. Furthermore, photosynthetic activity of treated plants exhibited a significant decline. The inhibition of growth in Pb and Cu-treated plants was accompanied by oxidative stress, as indicated by the enhanced lipid peroxidation and the high H2O2 concentration. Furthermore, antioxidants in citrus plants after exposure to high Pb and Cu concentrations were significantly increased compared to control and low Pb and Cu treatments. In conclusion, this study indicates that Pb and Cu promote lipid peroxidation, disrupt membrane integrity, reduces growth and photosynthesis and inhibit mineral nutrition. Considering the potential for adverse human health effects associated with high concentrations of Pb and Cu contained in edible parts of citrus plants the study signals that it is important to conduct further research into the accessibility and uptake of the tested heavy metals in the soil and whether they pose risks to humans

Effect of Salinity on Physiological and Biochemical Parameters of Leaves in Three Pomegranate (Punica Granatum L.) Cultivars

Salinity is one of the most important abiotic stresses affecting crop yield. It is important to exploit pomegranates&rsquo; potential against salts because they are considered beneficial plants for human health due to their antioxidants and they are often exposed to severe salinity stress in the field. Three pomegranate cvs. were chosen as model plants for assessing the impact of different salt stress in the cultivation. The aim of this study was to evaluate the physiological and biochemical response of three pomegranate varieties (Punica granatum L.) (Wonderful, Ermioni, and Grenada) under different saline conditions. The plants were grown in a sand/perlite substrate in a 1:1 ratio and, throughout the experiment, were irrigated with a Hoagland nutrient solution, modified to contain four concentrations (0, 25, 50, and 75 mM) of NaCl, KCl, and K2SO4. At the end of the experiment, we measured the (a) concentrations of carotenoids and porphyrin of leaves; (b) phenols and flavonoids contents, and antioxidant capacity of leaves; (c) lipid peroxidation level; (d) leaf water potential; and (e) proline concentration. Ermioni contained the maximum concentration of proline phenols and flavonoids and antioxidant capacity in all salts. Furthermore, reductions in chlorophyll and carotenoid concentration were recorded in all cultivars. Grenada possessed the lowest porphyrin concentration. In conclusion, our results showed that Grenada was the most salt-susceptible cultivar. Salinity treatment triggered the enhancement in lipid peroxidation in the sensitive cultivar, while no change in lipid peroxidation level was observed in the tolerant cultivars. These data provide further support to the hypothesis that a mechanism exists that excludes salinity from the roots of tolerant cultivars, as well as an internal mechanism of tolerance that minimizes the accumulation of lipid peroxides through a higher proline content related to osmoregulation and membrane stabilization

Response of Three Greek Populations of Aegilops triuncialis (Crop Wild Relative) to Serpentine Soil

A common garden experiment was established to investigate the effects of serpentine soil on the photosynthetic and biochemical traits of plants from three Greek populations of Aegilops triuncialis. We measured photosynthetic and chlorophyll fluorescence parameters, proline content, and nutrient uptake of the above plants growing in serpentine and non-serpentine soil. The photochemical activity of PSII was inhibited in plants growing in the serpentine soil regardless of the population; however, this inhibition was lower in the Aetolia-Acarnania population. The uptake and the allocation of Ni, as well as that of some other essential nutrient elements (Ca, Mg, Fe, Mn), to upper parts were decreased with the lower decrease recorded in the Aetolia-Acarnania population. Our results showed that excess Ni significantly increased the synthesis of proline, an antioxidant compound that plays an important role in the protection against oxidative stress. We conclude that the reduction in the photosynthetic performance is most probably due to reduced nutrient supply to the upper plant parts. Moreover, nickel accumulation in the roots recorded in plants from all three populations seems to be a mechanism to alleviate the detrimental effects of the serpentine soil stress. In addition, our data suggest that the population from Aetolia-Acarnania could be categorized among the nickel excluders

Effect of Salinity on Physiological and Biochemical Parameters of Leaves in Three Pomegranate (<i>Punica Granatum</i> L.) Cultivars

Salinity is one of the most important abiotic stresses affecting crop yield. It is important to exploit pomegranates’ potential against salts because they are considered beneficial plants for human health due to their antioxidants and they are often exposed to severe salinity stress in the field. Three pomegranate cvs. were chosen as model plants for assessing the impact of different salt stress in the cultivation. The aim of this study was to evaluate the physiological and biochemical response of three pomegranate varieties (Punica granatum L.) (Wonderful, Ermioni, and Grenada) under different saline conditions. The plants were grown in a sand/perlite substrate in a 1:1 ratio and, throughout the experiment, were irrigated with a Hoagland nutrient solution, modified to contain four concentrations (0, 25, 50, and 75 mM) of NaCl, KCl, and K2SO4. At the end of the experiment, we measured the (a) concentrations of carotenoids and porphyrin of leaves; (b) phenols and flavonoids contents, and antioxidant capacity of leaves; (c) lipid peroxidation level; (d) leaf water potential; and (e) proline concentration. Ermioni contained the maximum concentration of proline phenols and flavonoids and antioxidant capacity in all salts. Furthermore, reductions in chlorophyll and carotenoid concentration were recorded in all cultivars. Grenada possessed the lowest porphyrin concentration. In conclusion, our results showed that Grenada was the most salt-susceptible cultivar. Salinity treatment triggered the enhancement in lipid peroxidation in the sensitive cultivar, while no change in lipid peroxidation level was observed in the tolerant cultivars. These data provide further support to the hypothesis that a mechanism exists that excludes salinity from the roots of tolerant cultivars, as well as an internal mechanism of tolerance that minimizes the accumulation of lipid peroxides through a higher proline content related to osmoregulation and membrane stabilization

Comparative Approach on the Effects of Soil Amendments and Controlled-Release Fertilizer Application on the Growth, Nutrient Uptake, Physiological Performance and Fruit Quality of Pepper (Capsicum annuum L.) Plants

Under the economic pressure from the increase of fertilizers&rsquo; prices due to the recent energy crisis, more efforts are needed to search for alternative and cheaper sources of nutrients for crops. The purpose of our study was to compare the effects of manure and inorganic amendments&rsquo; application to those derived from the application of a controlled-release fertilizer (CRF) on the growth, nutrition, physiology and fruit quality of pepper plants. For that reason, zeolite (ZEO) and vermiculite (VER) were applied either independently, or in combination between them, or with manure (MAN), in a pot experiment. Insignificant differences for plant growth among the treatments were recorded, while higher foliar N, Mg and Mn concentrations were determined in CRF. In contrast, a significantly higher K uptake was recorded in the ZEO and VER + ZEO treatments; the highest leaf P levels (0.47 and 0.44% D.W.) were recorded in the MAN + VER and ZEO treatments, respectively. The optimum photosynthetic II (PSII) performance was observed in the VER and in the MAN + ZEO (based on the performance index&mdash;PI) treatments. The highest stomata opening was found in the CRF treatment, while the photosynthetic rate of pepper plants showed its maximum values both in the CRF and VER treatments. Finally, fruit quality (as indicated by total soluble solids, total phenols and antioxidant activity&mdash;FRAP) was significantly influenced by treatment. In conclusion, significant differences in the growth, nutrition and physiological performance of pepper plants between soil amendments&rsquo; application (inorganic, such as zeolite and vermiculite, and organic, such as manures) and CRF application were recorded; thus, these amendments should be more thoroughly studied in future projects to investigate if they could partially decrease high inorganic fertilization rates in Capsicum annuum L

Zeolite and Vermiculite as Inorganic Soil Amendments Modify Shoot-Root Allocation, Mineral Nutrition, Photosystem II Activity and Gas Exchange Parameters of Chestnut (<i>Castanea sativa</i> Mill) Plants

One of the most challenging topics for the sustainable agriculture is how to decrease high fertilization rates. A pot experiment, exploring the effects of zeolite (ZEO) and/or vermiculite (VER) as soil amendments, comparing to the soil application of a controlled release fertilizer (CRF), was realized in chestnut plants. Various parameters related to soil fertility, and plant growth, nutrition, and physiology were investigated to gain knowledge towards more sustainable management. After ZEO application and in comparison to CRF, an impressive boost in soil K was achieved. Moreover, soil P and Zn levels were higher in the VER-treated soil, compared to CRF. Leaf K and Ca concentrations were significantly higher in ZEO, compared to the VER treatment; the highest foliar N and Zn concentrations were measured in CRF and VER, respectively. However, significantly lower foliar Mn and Cu were found in VER. The highest root biomass produced in the ZEO treated plants. For most nutrients, their total uptake per plant was higher in CRF and ZEO. Finally, photosynthetic rates were higher in VER (mainly due to non-stomatal factors) and CRF (mainly due to stomatal factors). Our data open a discussion towards the application of ZEO and/or VER as soil amendments in chestnut nurseries and orchards, aiming at partially decreasing fertilization rates and boosting sustainable nutrient management