Spad

A recent non-destructive technique allows estimation of leaf chlorophyll content using the portable SPAD-502 chlorophyll meter. Measurements were taken on four species (winter wheat, maize, soyabean and tobacco) subjected to different nitrogen regimes or senescence status and the: non-destructive readings were compared with analytical results obtained by solvent extraction. In general, the relationship between the SPAD measurement and the analytical result was not linear and species was a factor in three out of four crops. Linear, quadratic and exponential curve fitting are presented; only die interpolation with a polynomial exponential function adequately descries the whole data set. The presence of statistically non-significant differences between the estimated values of wheat and maize on the one hand and significant: points of difference between those of tobacco and soyabean on the other suggests distinct behaviour patterns far monocots and cicots. This type of response maybe explained by differences, in the optical properties of pigments with differing sparial distributions (sieve effect) and therefore by in vivo and in vitro different procedures and the structural diversity of leaves belonging to the two subclasses.

ÖZET Bu çalışma, pamuk bitkisinin farklı azot dozlarının bitkinin fizyomorfolojik özelliklerinde oluşan değişimleri saptamak, bu fizyomorfolojik özellikler yardımı ile bitkideki azot durumunu tahmin etmek, geniş pamuk üretim alanlarında azot gereksinimlerini saptamak ve azot uygulama tavsiyelerinde bulunmak amacı ile Mardin ekolojik koşullarında, tesadüf parselleri deneme deseninde 3 tekerrürlü olarak yürütülmüştür. Çalışmada, fizyomorfolojik özellikler (yaprak azot içeriği, yaprak SPAD değeri, yaprak alan indeksi, NDVI) ve kütlü pamuk verimi özelliği incelenmiştir. İncelenen tüm fizyomorfolojik özellikler yönünden yaprak azot içerikleri arasında farklılıklar, istatistiki olarak önemli olduğu saptanmıştır. Yaprak azot içeriği ile incelenen tüm fizyomorfolojik özellikler aralarında ikili ilişkiler, istatistiki olarak önemli olduğu; yaprak azot içeriği ile yaprak SPAD değeri (R 2 : 0.44), yaprak alan indeksi (R 2 : 0.79) arasında linear ilişki, NDVI (R 2 : 0.42), kütlü pamuk verimi (R 2 : 0.65) özellikleri arasında ise quadratik ilişkinin olduğu saptanmıştır. ABSTRACT The aim of this study is to determine the changes in the physio-morphological properties of different plant nitrogen doses in cotton plant and to estimate the nitrogen status of the plant with these physio-morphological features, in order to determine nitrogen requirements in large cotton production areas and to advise on nitrogen application, it was carried out with 3 replications in randomized plot design in Mardin ecological conditions. Physio-morphological properties (leaf nitrogen content, leaf SPAD value, leaf area index, NDVI) and cotton yield were investigated. Differences between leaf nitrogen contents in terms of all physio-morphological characteristics examined were found to be statistically significant. Leaf nitrogen content and the relationship between all physio-morphological properties examined were statistically significant; leaf nitrogen content and leaf SPAD value (R 2 : 0.44), leaf area index (R 2 : 0.79), linear relationship between NDVI (R 2 : 0.42), cotton yield (R 2 : 0.65) was found to have a quadratic relationship.

Use of an in-season measure of crop N sufficiency to guide fertilizer management is one approach to match the supply of N to the crop N demand. This study examined use of gene expression in leaf tissue of field-grown potatoes for use in assessment of potato N sufficiency. Potato cultivar ‘Shepody’ was grown with six fertilizer N rates (0–250 kg N ha–1). Leaf disks were collected weekly for quantification of the expression of N uptake/transport, N assimilation, and amino acid metabolism genes in leaf tissue by nCounter. Many of the genes evaluated were responsive to crop N supply, but the response varied widely among sampling dates. The exception was an ammonium transporter gene (AT1) which was highly expressed, was relatively consistent across sampling dates, was closely related to root zone soil nitrate concentration across N rates and sampling dates, and was highly negatively correlated with total tuber yield. The level of expression of AT1 in leaf tissue was as good as or better than conventional chemical or optical measures of potato N sufficiency in the current study.

Ο Cohen (1972), ήταν ένας από τους πρώτους ερευνητές ο οποίος πρότεινε ότι οι τουρίστες θα μπορούσαν να ταξινομηθούν με βάση παρόμοιες παρατηρήσιμες συμπεριφορές. Οι Gibson και Yiannakis (2002),  παρουσίασαν μια περιεκτική ταξινόμηση των τουριστών ελεύθερου χρόνου και σχεδίασαν την κλίμακα Tourist Role Preference Scale (TRPS) τουριστικής τυπολογίας 15 ρόλων. Ο σκοπός της παρούσας έρευνας ήταν να διερευνήσει την τυπολογία των τουριστών, που επισκέπτονται την Ελλάδα, καθώς και τον αθλητικό τουρισμό στη χώρα. Το δείγμα αποτελούνταν από 1675 τουρίστες από 50 χώρες, που επισκέφτηκαν την Ελλάδα το καλοκαίρι του 2007. Το ερωτηματολόγιο που χρησιμοποιήθηκε ήταν βασισμένο στο TRPS και στην τελική μορφή του έγιναν κάποιες προσθήκες και τροποποιήσεις. Έπειτα, μεταφράστηκε στην ελληνική, γερμανική και ρωσική γλώσσα και αποτελούνταν από 89 ερωτήσεις. Τα ερωτηματολόγια διανεμήθηκαν σε τουρίστες στο χώρο των αναχωρήσεων και μετά τον έλεγχο (check-in), στους αερολιμένες «Ελ.Βενιζέλος» στην Αθήνα και «Μακεδονία» στη Θεσσαλονίκη. Για να εξακριβωθεί η ισχύς της κλίμακας και να καθοριστούν οι τουριστικοί ρόλοι χρησιμοποιήθηκε η ανάλυση ταξινόμησης (SPAD), με την οποία έγινε ομαδοποίηση των γραμμών των τουριστικών συμπεριφορών και είχε ως αποτέλεσμα τη δημιουργία δέκα κλάσεων. Επίσης, πραγματοποιήθηκαν η ανάλυση κυρίων συνιστωσών και η πολυδιάστατη κλιμακοποίηση. Τα αποτελέσματα της έρευνας έδειξαν ότι το TRPS φαίνεται να είναι εφαρμόσιμο στη Ελλάδα. Συμπερασματικά, ο Εραστής του Ήλιου, ο Ανθρωπολόγος, ο Αρχαιολόγος, ο Ανεξάρτητος Μαζικός Τουρίστας και ο Φυγάς από την Πραγματικότητα συγκεντρώνουν τα μεγαλύτερα ποσοστά και αυτό σημαίνει απώλεια τουριστών στις υπόλοιπες μορφές. Πιθανά ένας λόγος είναι το μη ικανοποιητικό μάρκετινγκ του τουριστικού προϊόντος και η έλλειψη οργάνωσης και προώθησης νέων μορφών τουρισμού σε αυτούς που απασχολούνται ή θα ήθελαν να απασχοληθούν με τον τουρισμό στην Ελλάδα.

Bare-root transplants of strawberry (Fragaria ananassa Duch. cv. 'Selva') were transferred to nutrient solutions with or without iron (Fe). After six weeks of growth, plants grown in solution lacking Fe were chlorotic and showed morphological changes in roots typical of Fe deficiency. Subsequently, four treatments were applied for nine days: plants grown in continued absence of Fe (Fe0); plants grown in continued presence of 10 μM Fe (Fe10); foliar application of ferrous sulphate every two days to chlorotic plants (Fe-leaves); and growth of chlorotic plants in solution with ferrous sulphate (Fe-solution). After six days, the chlorophyll (Chl) content in leaves of Fe-solution plants was similar to that in Fe10 plants. Under the Fe-leaves treatment, a slight regreening of new leaves was observed only by the end of the experiment. After nine days, ferric chelate reductase (FC-R) activity was unchanged in Fe10 but increased in Fe0 plants. The FC-R activity of Fe-solution plant...

ABSTRACT Citrus trees growing in the Mediterranean region suffer from iron (Fe) deficiency because of the presence of high levels of carbonate ions in calcareous soils. In this context we have evaluated the effects of different citrus rootstocks on photosynthetic capacity and plant development of young 'Navelina' orange trees under Fe deprived conditions. Leaf number, shoot length, plant dry mass, leaf chlorophyll (Chl) concentration, net photosynthetic rate (P-N), stomatal conductance (g(S)), leaf transpiration rate (E), intercellular CO2 concentration (C-i) and photosynthetic water use efficiency (WUE) of 'Navelina' orange scion budded on to eight citrus rootstocks with different agronomic characteristics were investigated. Significant decreases in leaf number, shoot length and plant dry mass under high pH conditions were observed. Plants on Tuzcu 31 31 and Gou Tou sour orange rootstocks were the least affected in terms of plant growth. The highest reduction in the leaf Chl content was observed in (-)Fe plants of Navelina on local trifoliate and C-35 citrange. These rootstocks also had significantly reduced PN, gS and E rates in the (-)Fe treatment. Shoots budded on Tuzcu 31 31 and Gou Tou sour oranges were the least affected by the induced Fe deficiency.

Various biotic and abiotic stresses adversely affect crop yield across
the globe. Wheat is a cool-season cereal crop and sensitive to rise in
ambient growth temperature. Ninety genotypes were screened under
heat stress and non-heat stress locations. Low heat susceptibility index
of <0.5 for HD2189, NI5643, Kenphad39, HD2501, NI179, N5439, HS240,
HD2428 and HD2687 indicated that they are heat tolerant and high
susceptibility index of >1.5 for PBN142, NI9947, HD2320, GW190,
HD2135, NI917 and Batavia indicated that they are heat susceptible.
Based on grain yield and heat susceptibility index, two genotypes
namely HD2189 and Batavia with contrasting response to heat
stress were selected for the further studies. Their morphological and
physiological characterization was carried out at seedling stage using
22°C as control and 33°C as heat stress. Under heat stress conditions,
reduction for seedling growth traits, relative water content (RWC) and
membrane thermostability (MTS) was less in HD2189 (25.3%, 10.2%,
13%) compared to Batavia (55.3%, 34.4%, 30%). HD2189 maintained
lower canopy temperature with depression values in the range of
3.75 to 8°C compared to Batavia (2.82 to 5.10°C). The conversion of
source to sink was better for HD2189 as displayed by translocated
dry matter (TDM), translocation efficiency (TE), contribution of plant
assimilates (CPA), longer duration of grain filling, grain yield and yield
components under high temperature. Trend for electron transport rate
of PSII (ETRII) and effective quantum yield (YII) for both the varieties
at 22°C and 33°C was similar. However, Batavia plants were adjusting
through non-regulated heat dissipation indicating damage to the
photosynthetic apparatus whereas HD2189 showed higher regulated
heat dissipation. Thus, genotype HD2189 showed heat tolerance at
seedling and adult plant stages compared to Batavia.