Morphological (dry mass, DM; surface area, LA; leaf mass per area, LMA), anatomical (leaf thickness, L), phenological (leaf life span, LL), and physiological (net photosynthetic rate, PN) leaf traits of the evergreen species co-occurring in the Mediterranean maquis developing at Castelporziano (Rome) were tested. The correlation analysis indicated that LMA variation was tightly associated with LL variations: Cistus incanus and Arbutus unedo had a short LL (4±1, summer leaves, and 11±1 months, respectively) and low LMA (153±19 g m-2) values, Quercus ilex, Phillyrea latifolia, and Pistacia lentiscus high LMA (204±7 g m-2) and long LL (22±3 months), Erica arborea, Erica multiflora, and Rosmarinus officinalis a short LL (9±2 months) and an either high (213±29 g m-2, R. officinalis and E. multiflora) or low (115±17 g m-2, E. arborea) LMA. LMA values were significantly (p≤0.05) correlated with PN (r≥0.68). In the tested species, LMA increased in response to the decrease of the total rainfall during the leaf expansion period. LMA variation was due to the unequal variation of DM and LA in the considered species. LMA is thus a good indicator of evergreen maquis species capability to respond to climate change, in particular to total rainfall decrease in the Mediterranean basin. and L. Gratani, L. Varone.
Genotypic variations were observed among 6 variants and an indigenous one as a control. An efficient genotype OCD(L) of Ocimum sanctum had the greatest content of chlorophylls [2.15 g kg-1(FM)], Chl a/b ratio of 1.86, net photosynthetic rate of 0.72 mg(CO2) m-2 s-1, and 1.56 % oil formation. Methyl chavicol formed 50.31 % of total oil in OSP-6 genotype, which had also maximum peroxidase activity [ΔOD 2.4 mg-1(protein)] and maximum production of eugenol (30.44 % of total oil). We found an oxido-reducible reaction of peroxidase and high bands of peroxidase isoenzymes in this OSP-6 genotype for the formation of monoterpene essential oil(s) and possibly the major constituents of eugenol through the high production of photosynthates. and A. Misra ... [et al.].
Net photosynthetic rate (PN) was studied in field-grown peanut cv. GG 2 in relation to leaf position, time of day, reproductive-sink, and phenophase. In general, PN remained higher in the upper leaves (first from top to the fourth) than in the lower leaves (fifth to eighth). The mean PN of the leaves situated upper and the leaves lower in the canopy increased from the morning, reached a maximum during noon hours, and decreased thereafter. Between 09:00 to 10:00 h, PN, stomatal conductance (gs), and transpiration rate (E) in the upper leaves were higher than in the lower leaves, but between 12:00 and 13:00 h, these activities increased significantly in the lower leaves. Highest PN was found during pod-development phase. Removal of flowers, and hence of active reproductive-sink, decreased plant height and number of leaves, and initiated accumulation of photosynthates in the leaves. The PN per unit leaf area in plants with reproductive-sink (WRS) was similar to those without reproductive-sink (WORS). However, leaf area of WORS plants decreased significantly, mainly due to the reduction in number of leaves. No feed-back inhibition of PN (per unit leaf area) was found despite accumulation of photosynthates in the leaves as a result of removal of the active reproductive-sink. and P. C. Nautiyal, V. Ravindra, Y. C. Joshi.
Available water stored in deep soil layers could increase the photosynthetic capacity of cotton. It was hypothesized that the photosynthesis of cotton would be enhanced by changing the fertilizer application depth under different deep-layer water conditions. We examined two deep-layer water levels, i.e.,
well-watered (W80) and not watered (W0), combined with surface application (F10) and deep application (F30) of basal fertilizer. Compared to W0, W80 resulted in increased leaf area (LA), photosynthetic pigment contents, maximal PSII efficiency (Fv/Fm), effective quantum yield of PSII (YII) and PSI (YI), electron transport rate of PSII (ETRII) and PSI (ETRI). W80 also increased the aboveground and root dry mass by 39 and 0.6%, respectively, and decreased the root/shoot ratio by 40-73%. Under the W0 condition, higher values of Fv/Fm, YII, YI, ETRII, and ETRI were measured for F10 compared to F30 after 69 d from emergence. Under the W80 condition, cotton plants with F10 showed higher LA, Fv/Fm, YII, YI, ETRII, and ETRI, but there were no significant differences in the photosynthetic pigments compared to F30. Our results suggest that sufficient water in deeper soil layers and the surface application of basal fertilizer could increase photosynthetic activity and efficiency, which promoted aboveground dry mass accumulation and partitioning towards reproductive organs., Z. K. Chen, Y. P. Niu, H. Ma, A. Hafeez, H. H. Luo, W. F. Zhang., and Obsahuje seznam literatury
The effects of water deficit and re-irrigation were studied in glasshouse-grown rice plants (cvs. Cimarrón and Fonaiap 2000) which differ in their susceptibility to water deficit. Relative water content decreased from >90 to 67-69 % and recovered to pre-stress values within 24 h after re-irrigation. The irradiance-saturated rate of photosynthesis (Psat), transpiration rate (E), and stomatal conductance (gs) decreased with water deficit. E and gs decreased similarly in both cultivars, but Psat was more strongly inhibited in Cimarrón than in Fonaiap 2000. Water deficit increased water use efficiency (WUET) over 2-fold in Fonaiap 2000 and by 1.5-fold in Cimarrón. The ratio of intercellular to ambient CO2 concentration (Ci/Ca) decreased in Fonaiap 2000 during mild stress but increased at severe stress. Contrarily, Cimarrón did not change Ci/Ca with water deficit. After re-irrigation Fonaiap 2000 recovered Psat to ca. 80 % of control values 24 h after re-irrigation, whereas Cimarrón recovered to 60 % of control values 48 h after re-irrigation. E and gs recovered to a lesser extent (50 %) than
Psat, after 48 h of re-irrigation in both cultivars. Total aboveground and green (live) biomass were unaffected by water deficit in Fonaiap 2000 but were reduced by 21 and 40 % in Cimarrón, respectively. Dead biomass increased in stressed plants of both cultivars but to a larger extent in Cimarrón than in Fonaiap 2000. Water deficit increased δ13C in Fonaiap 2000, whereas Cimarrón was unaffected by water deficit showing lower values than those of Fonaiap 2000. δ13C was highly and linearly correlated to the ratio
Ci/Ca. WUET was also significantly correlated to δ13C. and A. J. Pieters, M. Núñez.
Seedlings of Chrysanthemum, cultivar 'Puma Sunny', were grown under a range of shading regimes (natural full sunlight, 55, 25, and 15% of full sunlight) for 18 days. Here, we characterized effects of varying light regimes on plant morphology, photosynthesis, chlorophyll fluorescence, anatomical traits, and chloroplast ultrastructure. We showed that leaf color was yellowish-green under full sunlight. Leaf area, internode length, and petiole length of plants were the largest under 15% irradiance. Net photosynthetic rate, water-use efficiency, PSII quantum efficiency, and starch grain were reduced with decreasing irradiance from 100 to 15%. Heavy shading resulted in the partial closure of PSII reaction centers and the CO₂ assimilation was restricted. The results showed the leaves of plants were thinner under 25 and 15% irradiance with loose palisade tissue and irregularly arranged spongy mesophyll cells, while the plants grown under full sunlight showed the most compact leaf palisade parenchyma. Irradiance lesser than 25% of full sunlight reduced carbon assimilation and led to limited plant growth. Approximately 55% irradiance was suggested to be the optimal for Chrysanthemum morifolium., S. Han, S. M. Chen, A. P. Song, R. X. Liu, H. Y. Li, J. F. Jiang, F. D. Chen., and Obsahuje bibliografii
Aqueous solutions of salicylic acid (SA) were applied to the foliage of 30-d-old plants of mustard (Brassica juncea Czern & Coss cv. Varuna). The plants sprayed with the lowest used concentration (10-5 M) of SA were healthier than those sprayed with water only or with higher concentrations of SA (10-4 or 10-3 M). 60-d-old plants possessed 8.4, 9.8, 9.3, 13.0 and 18.5 % larger dry mass, net photosynthetic rate, carboxylation efficiency, and activities of nitrate reductase and carbonic anhydrase over the control, respectively. Moreover, the number of pods and the seed yield increased by 13.7 and 8.4 % over the control. and Q. Fariduddin, S. Hayat, A. Ahmad.
Of the four tested sweet potato cultivars having different features in growth and yield, cv. Koganesengan (KOG) was sustainable in photosynthetic activity through young to aged leaves under drought. One of the causes for this phenomenon may be stomatal conductance (g s) of this cultivar that was relatively high in both aged and drought-imposed leaves. In these leaves the non-photochemical quenching (NPQ) was low and the quantum yield of photosystem 2 (Φe) was high, compared to those of the other cultivars. This helps to prevent excessive accumulation of chemical energy in leaves and a decrease in photoinhibition damage to the photosynthetic function, by which KOG sustains a relatively high photosynthetic activity under the drought and alleviates functional deterioration caused by leaf age. and Haimeirong, F. Kubota.
Culturing geranium at different doses of Zn from 0-1.0 g m-3 (Zn0 to Zn1.000) revealed that Zn is an antioxidant promoter, apart from its micronutrient essentiality. Zn0.250 was the critical concentration for maximum content (0.21 %) of total essential monoterpene oil(s). At Zn0.005-Zn0.250, net photosynthetic rate, and contents of chlorophyll and essential monoterpene oil(s) were affected. The maximum peroxidase activity was obtained at Zn0.250, with the production of biomolecule geraniol. We found an oxido-reducible reaction of Zn in the formation of monoterpene essential oil(s) and possibly major constituents of geraniol. and A. Misra ... [et al.].