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January 2008

Table of Content
                                                                                                                (PDF Link)
Iridoid and flavonoid patterns of the genus Veronica sect. Alsinebe subsect. Agrestis (Benth.) Stroh (Lamiales) and their systematic significance                                                                                                               

Shahryar Saeidi Mehrvarz, Nosrat O. Mahmoodi , Roshanak Asadian and Gholamreza Bakhshi Khaniki                                                                      
Distribution of two iridoid and 6 flavonoid compounds in four Veronica sect. Alsinebe subsect. Agrestis species (23 samples) from Iranian natural populations was investigated. Veronica francispetae and V. siaretensis were studied for these compounds for the first time. The iridoid and flavonoid patterns showed a good correlation with other chemical and morphological features of these taxa. The studied species are closest together according to the flavonoid patterns: species containing quercetin derivatives are V. persica, V. polita and species containing quercetin are V. francispetae, V. siaretensis.

Keywords: Veronica; iridoid; flavonoid; chemosystematic; Iran.

Micromorphological, morphological and anatomical investigation of the Lilium ledebourii (Baker) Bioss.(Liliaceae) indigenous to Iran                                                                                                                                         
                                                                                                                 (PDF Link)
Behzad Kaviani

This study presents investigations on the morphological, micromorphological and anatomical features of Lilium ledebourii (Baker) Bioss. an endemic rare and very attractive ornamental species in Iran. Visual, micromorphological and anatomical investigations were performed by comparing of the species with the Flora of Iran, scanning by electron microscopy (SEM) and sectioning of various organs, respectively. The studies have been revealed that there are some particular, unique properties in this species.

Lilium ledebourii (Baker) Bioss; Anatomy; Morphology; Micromorphology; Endemic.

Synergic effect of N and moisture on biochemical property of nodules and seed yield in chickpea                                                              (PDF Link)

Gan YT , Jayakumar P , Symons S , and McDonald CL

Water stress often has a negative effect on nodulation and seed yield in legumes but this effect can be minimized through N management. This study determined the synergic effect of water stress and N fertilization on the biochemical property of nodules, biomass partitioning among shoot, roots and nodules, and seed yield in chickpea. The cultivar ‘CDC-Frontier’ inoculated with and without Mesorhizobium cicer was grown at various rates of N fertilizer under high (90% field capacity), medium (60%) and low (30%) moisture levels in controlled environments. There was a significant synergic effect of N and moisture on nodulation and productivity. The seed yield of non-inoculated chickpea receiving zero N (0N) was reduced by 174% at high, 90% at medium, and 50% at low moisture levels compared to chickpea receiving 60 kg N ha-1(60N). As soil moisture declined from high to low, the seed yield of inoculated chickpea supplied with 20 to 40N were reduced by 25%, significantly less than the yield loss of 58% for the plants supplied with 0N. Presence of N allowed a lower accumulation of amides in nodules and more N were kept in the nodules. The use of N fertilizer reduced the negative effect of water stress by partitioning more biomass to roots. Stronger root systems allowed plants to absorb more water for the transport of fixed N. In practice, yield losses from ineffective nodulation due to water stress can be minimized with the use of low doses of fertilizer N in chickpea.

Cicer arietinum; moisture stress; N2 fixation; fertilizer N; Shoot:root ratio

Identification of physiological traits and genotypes combined to high achene yield in sunflower (Helianthus annuus L.) under contrasting water regimes                                                                                      (PDF Link)

Saeed Rauf, Hafeez Ahmad Sadaqat

Field experiments were conducted to determine the effect of different leaf hydraulic traits on achene yield in sunflower under irrigated and drought regimes. Among leaf hydraulics, stomatal conductance (gs) showed highest relationship with achene yield (ay) under irrigated regime while in drought; osmotic adjustment (OA) showed highest positive relationship with ay. Presence of highly strong relationship between OA and relative water contents (RWC) indicated that RWC contents may be utilized as physiological marker of OA when source material comprises of different genotypes. Further more RWC contents also showed highly significant relationship with ay. OA also showed significant relationship with turgor pressure (TP) suggesting its role in maintenance of turgor. Genotype AMES-10107 showed highest ay which was accompanied by the higher gs in non stress regime. However under drought stress, AMES-10103 showed highest ay. This genotype also showed highest OA, RWC and TP.

  Drought; Osmotic adjustment; Relative water contents; Stomatal conductance; Turgor pressure.

Comparative response of drought tolerant and drought sensitive maize genotypes to water stress                                                   (PDF Link)

1Helal Ragab Moussa and 2Samir Moustafa Abdel-Aziz

Maize genotypes Giza 2 (drought tolerant) and Trihybrid 321 (drought sensitive) were sown in the small pots under laboratory condition. Water stress condition was created by irrigating the pots with polyethylene glycol (PEG) solutions of 0.0, -5, -10 and -20 bars and observations were made on 21-day-old seedlings. The tolerant genotype Giza 2 exhibited lower accumulation of malondialdehyde (MDA) and H2O2 content related to increasing activities of superoxide dismutase (SOD, EC, catalase (CAT, EC, and peroxidase compounds (POX, EC, under water stress conditions. The higher water retention capacity and lower membrane injury made Giza 2 more drought tolerant. Drought stress was resulted by accumulation of gylycinebetain (GB) and free proline (PRO) in both cultivars. The magnitude of increase in both omsolytes was higher in Giza 2 than in Trihybrid 321. We suggest that free proline and gylycinebetaine accumulation in the leaves can be used as the possible indicator for drought tolerance in maize genotypes. Water deficits induced an increased level of photosynthetic activity (14CO2-fixation) in Giza 2 than Trihybrid 321.  Therefore, it can be concluded that the stress tolerance mechanism exists at seedling stage of maize genotypes. The Giza 2 is comparatively tolerant to water stress owing to the lower increase in H2O2 and MDA content along with higher increase in PRO, GB accumulation, photosynthetic efficiency, SOD, CAT and POX activities. The higher membrane stability index and high water retention capacity might have also imparted water stress tolerance in Giza 2. Further, Trihybrid 321 was also able to resist water stress to some extent via the above adjustments.

Keywords : Photosynthesis; gylycinebetain; antioxidant enzyme; Zea mays.