Effect of Organic Fertilizers on Avocado Trees (Cvs. Fuerte, Hass, Lamb Hass) in Western Crete, a Cool Subtropical Region

The market for avocado is one of the fastest expanding worldwide, inclduing the Mediterranean basin. Organic farming systems cannot make use of synthetic fertilizers and therefore rely on several cultural techniques to maintain vigorous young trees and for quick shoot development, satisfactory yield, and fruit quality. We studied the effect of three different organic products (Terra Insecta (R) (Aeiphoria-Sustainable products of Crete, Chania, Greece), Fruit-Fix (R), and AMINO-16 (R) (both products manufactured by EVYP, Sindos, Thessaloniki, Greece) on avocado plants in the cool subtropical area of southern Greece. Three experiments were carried out, two of them on young avocado trees, and the third one on mature, fully productive trees. The establishment success (ES) (%), plants with shoot induction (SI) (%), plants with shoot growth >= 3 cm (SG) (%), number of sprouted buds >= 3 cm per plant (SB), mean shoot length (cm) per plant (SL), total shoot length (cm) per plant (TSL), mean leaf number per plant (LN), and total leaf number per plant (TLN) were measured in the first and second experiments, while in the third experiment, fruit growth parameters (length, width, fruit weight, fruit weight increase (FWI)) and fruit quality parameters (dry matter, oil concentration, dry matter, and oil concentration increase) were measured. The application of 0.2 K of Terra Insecta (R) to the planting hole did not have any statistically significant effect on plant growth, but when added around the trunk, statistically higher values were observed for SB, SL, LN, TSL, and TLN in the Terra Insecta (R) treatment compared to the control. Fruit-Fix (R) application to Lamb Hass avocado trees resulted in significant differences in ES, SI, SG, SL, TSL, LN, and TLN, and in the Hass variety, in SB. In the AMINO-16 (R) experiment, the fruit dimensions, quality parameters, and yield of the Hass variety were not recorded as significantly different. However, in the Fuerte variety, FW increased by 119.3% in the AMINO-16 (R) treatment. The effect of the organic fertilizers used in this research showed noticeable results requiring studies to be carried out over more seasons, different tree ages, cultivation methods, and stress conditions

Extraction of phenolic and flavonoid compounds and evaluation of their antioxidant activity in saffron anthers (Crocus sativus L.)

Saffron (Crocus sativus L.) is the most expensive spice in the world and rich in a variety of bioactive compounds including phenolic acids, flavonoids, and vitamins. Saffron is used in food, cosmetics, perfumery, and dye industries due to its color, taste, aroma, and medicinal properties. The extraction of bioactive compounds imposes a constant search for economically and environmentally viable extraction strategies for higher yields including the solvent type. The research was carried out to evaluate total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activity of C. sativus L. anthers using different extraction solvents including ethanol, methanol, and distilled water. The results showed that ethanol was the most effective extraction solvent type exhibiting the highest TPC (7.29 mg GAE g-1 DW), TFC (3.77 mg QE g-1 DW), and antioxidant activity of flavonoids (88%) and ascorbic acid (76.07%). Flavonoids proved to be stronger antioxidants than ascorbic acid, irrespective of solvent type, however the ethanolic extracts showed significantly higher antioxidant activity. A Reverse Phase High-Performance Liquid Chromatography method revealed that gallic acid (3.1 mg g-1), syringic acid (0.2 mg g-1), and vanillic acid (0.13 mg g-1) were the main phenolic compounds detected in the dried anther ethanolic extracts, while quercetin (2.13 mg g-1), pyrogallol (1.73 mg g-1), kaempferol (1.2 mg g-1), rutin (0.2 mg g-1), and tricin (0.1 mg g-1) the main flavonoid compounds. Thus, apart from the spice, constituted by the red stigmas, the production of other flower parts such as the anthers, so far considered agricultural waste can constitute a rich source of bioactive compounds of high antioxidant potential by setting quality standards for new products’ development and ensuring better valorization of saffron’s bioresidues in Mashhad region of Iran

Micropropagation and molecular characterization of Hypericum perforatum L. subsp. veronense (Schrank) H. Lindb., a valuable medicinal plant with ornamental value

St. John's wort (Hypericum perforatum) is a perennial species with a worldwide interest due to its pharmaceutical characteristics which is also of ornamental value for gardening with native elements. Given that in vitro culture allows mass multiplication of selected genotypes, we investigated the micropropagation of the ex situ cultivated Greek native H. perforatum subsp. veronense using novel substances and its genetic fingerprinting. Apart from common auxins and cytokinins, a culture medium (BB) was used for the first time for its micropropagation and the effect of betaine, PVP, SNP and triacontanol were explored for the first time. Betaine addition of 200 mg/L produced proliferated shoots and roots without the need of plant growth regulators although a 0.5 mg L-1 BA was the best treatment in proliferation experiments. Shoot number was highest in 0.5 BA + 0.1 IBA (mg L-1), in 1 μΜ sodium nitroprusside (SNP) + 1 mg L-1 IAA+200 mg L-1 betaine and in PVP (0.5-1.5 mg L-1) + 1 mg L-1 IBA + 200 mg L-1. Greater SNP concentration had either no differences or negative effect, while the greatest root number were recorded in Control. All three treatments of triacontanol (1-10 μg L-1) + 0.5 mg L-1 BA + 200 mg L-1 betaine resulted in higher shoot number. However, the statistically greatest root number were recorded in low concentration of SNP, or in absence of PVP and triacontanol. The micro-plants of H. perforatum subsp. veronense obtained from the SunCapTM sealed vessels and transplanted into the soil substrates presented 90.2% success; they were then transplanted to 1 L pots and were successfully established in the field for cultivation. The molecular characterization of H. perforatum subsp. veronense was achieved with DNA barcoding fingerprints deposited in the GenBank regarding four molecular markers of cpDNA (petB/petD, rbcL, trnL/trnF and rpoC1)

Factors affecting in vitro organogenesis in three citrus rootstocks

Citrus culture has a great economical significance for many countries all over the world including Greece. The choice of the appropriate rootstock ensures high productivity and excellent fruit quality. The aim of this dissertation was to study micropropagation of three citrus rootstocks namely Trifoliate orange (Τ.Ο.), Sour orange (S.Ο.) and Citrumelo (Ct.). In an effort to separate zygotic from nucellar plant material different DNA isoforms were observed in cotyledons from Τ.Ο. and S.Ο. seeds. In zygotic plant material, smaller number of isoforms was observed. Concerning endogenous protein phosphorylation during seed germination, differences were recorded in the number and intensity of peptide bands of NDP kinases. To study how the culture medium and growth regulators affect organogenesis, shoot tips explants were cultured in the MS substrate containing several concentrations of various regulators agar and sucrose and various pH levels. The data indicate that only certain parameters of three citrus rootstocks were influenced positively by several treatments. The study of organogenesis from epicotyl explants, mature shoot tips explants, mature leaves and root tip explants had a positive effect on certain cases. Green globular bodies and shoots were developed from root tip explants of Τ.Ο. and Ct. as a response to addition in the substrate of different growth regulators. From the anatomical study of the root tip explants and the green globular bodies, variations in structure and anatomy of roots were observed (secondary root growth was recorded in comparison to control). Moreover this study indicates that the green globular bodies containing parenchymatic cells multiply by mitotic division. The study of DNase activity of green globular bodies indicated that exogenous application of growth regulators increased DNase activity. Also, the activity of NDP kinases was influenced by the increase of BA concentration alone and in combination with other growth regulators. As a result, different peptide bands of NDP kinases were observed. Overall, the purpose of this dissertation was the separation of zygotic from nucellar seedlings in order to take the desirable plant material, and the answer of biochemical and anatomical questions about organogenesis of three commercial citrus rootstocks. Furthermore, the final aim of this study was the development of an efficient protocol for micropropagation of these citrus rootstocks. The determination of optimal conditions for their mass propagation is very important, as they have desirable characteristics and they are used widely in agriculture.Τα εσπεριδοειδή αποτελούν μια καλλιέργεια μεγάλης οικονομικής σημασίας τόσο για την ελληνική όσο και για την παγκόσμια οικονομία. Τα κατάλληλα υποκείμενα είναι η πρώτη από μια σειρά επίλογων που θα διασφαλίσουν μια ποιοτική και υψηλή παράγωγη. Σκοπός της διατριβής ήταν η διερεύνηση του μικροπολλαπλασιασμού τριών υποκειμένων εσπεριδοειδών, της Τρίφυλλης πορτοκαλιάς, της Νεραντζιάς και του Citrumelo. Για την επίτευξη του παραπάνω σκοπού εξετάστηκε αρχικά η ενζυμική δραστηριότητα των νουκλεολυτικών ένζυμων και των κινασών των διφωσφονουκλεοζιτών σε σπέρματα με σκοπό το διαχωρισμό εγγενών και απομικτικών αποροφύτων. Στην προσπάθεια χαρακτηρισμού του φυτικού υλικού ως εγγενούς ή απομικτικού παρατηρήθηκαν λιγότερες ισομορφές DNασών σε σχέση με απομικτικά σπορόφυτα σε κοτυληδόνες από σπέρματα Τρίφυλλης πορτοκαλιάς και Νεραντζιάς. Όσο αφορά την ενδογενή πρωτεϊνική φωσφορυλίωση διαπιστώθηκαν διαφορές στον αριθμό και την ένταση των πεπτιδικών ζωνών των NDP κινασών. Για να μελετηθεί πως επιδρούν οι παράγοντες του υποστρώματος και οι ρυθμιστές αύξησης στην οργανογένεση, βλαστικές κορυφές εγκαταστάθηκαν σε θρεπτικό υπόστρωμα MS που περιείχε διαφορετικές συγκεντρώσεις ρυθμιστών άγαρ σακχαρόζης και τιμές pH. Και στα τρία υποκείμενα μόνο ορισμένες παράμετροι επηρεάστηκαν θετικά από τις διαφορετικές μεταχειρίσεις. Μελετήθηκε επιπλέον η οργανογένεση από έκφυτα επικοτύλης, ώριμους βλαστούς, ώριμα φύλλα και ρίζες με θετικά αποτελέσματα σε κάποιες μεταχειρίσεις. Συγκεκριμένα η επίδραση ρυθμιστών αύξησης προκάλεσε το σχηματισμό πράσινων σφαιρικών σωματίων και βλαστογένεση σε ριζικά έκφυτα Τρίφυλλης πορτοκαλιάς και Citrumelo. Πραγματοποιήθηκε επιπλέον ανατομική μελέτη στα ριζικά έκφυτα των τριών υποκείμενων για να προσδιοριστεί η επίδραση διαφορετικών μεταχειρίσεων στην οργανογένεση. Παρατηρήθηκαν διαφορές στην ανατομία της ρίζας (δευτερογενής αύξηση σε σχέση με τους μάρτυρες). Επιπλέον διαπιστώθηκε πως τα σφαιρικά σωμάτια αποτελούνται από παρεγχυματικά κύτταρα και πολλαπλασιάζονται μεταξύ τους με μιτωτική διαίρεση. Επίσης εξετάστηκε η ενζυμική δραστηριότητα στα σφαιρικά σωμάτια και προέκυψε πως οι ρυθμιστές αύξησης επηρέασαν τον αριθμό ισόμορφων των DNασών και τη δράση των NDP κινασών με αποτέλεσμα το σχηματισμό διαφορετικών πεπτιδικών ζωνών και διαφορετικής έντασης. Απώτερος στόχος της διατριβής ήταν η απάντηση βιοχημικών και ανατομικών ερωτημάτων καθώς και η διατύπωση ενός ενδεδειγμένου πρωτοκόλλου εργασίας για το μικροπολλαπλασιασμό των τριών υποκειμένων, που θα έχει πρακτική άξια στον εμπορικό πολλαπλασιασμό τους. Ο προσδιορισμός των κατάλληλων συνθηκών για τη μαζική παράγωγη τους αποκτά σημαντική άξια, καθώς εμφανίζουν επιθυμητά χαρακτηριστικά και χρησιμοποιούνται ευρέως

Micropropagation of guava (Psidium guajava) seedlings, a plant with interest in cool subtropics, using an innovative BB culture medium

AbstractPsidium guajava is a new crop cultivated in Greece, with a potential pharmaceutical and ornamental uses. An efficient and reliable protocol for in vitro clonal propagation of P. guajava from seeds was used. Five different media were examined. Shoot proliferation succeeded on a new basal medium (BB) supplemented with a modified vitamin solution (vit BB), without plant growth regulators. In addition, shoots on media supplemented with BB vitamin solution performed better than in Murashige and Scoog (MS) and Woody Plant (WP) media. When BB medium was used, the greatest shoot number resulted in 4 mg L−1 6-benzyladenine (BA) with a score of 2.8. Regenerated single shoots were rooted in the BB medium, supplemented with 0.1 ΝΑΑ (mg L−1) and producing 2.2 roots of 4.6 cm, along with 3.1 cm of adventitious shoots. Acclimatization was accomplished in three phases, using peat-moss, vermiculite and perlite (1:1:1), with a total survival of 83.3%. To examine the genetic diversity of the plant material, Inter Simple Sequence Repeat (ISSR) and Start Codon Targeted (SCoT) molecular markers were used. The results indicated a low diversity, along with high percentage of polymorphism for both ISSR and SCoT analyzes