The effect of arbuscular mycorrhizal fungi (AMF) inoculation and organic slow release fertilizer (OSRF) on photosynthesis, root phosphatase activity, nutrient acquisition, and growth of Ipomoea carnea N. von Jacquin ssp. fistulosa (K. Von Martinus ex J. Choisy) D. Austin (bush morning glory) was determined in a greenhouse study. The AMF treatments consisted of a commercial isolate of Glomus intraradices and a non-colonized (NonAMF) control. The OSRF was applied at 10, 30, and 100 % of the manufacturer's recommended rate. AMF plants had a higher net photosynthetic rate (PN), higher leaf elemental N, P, and K, and generally greater growth than NonAMF plants. Total colonization levels of AMF plants ranged from 27 % (100 % OSRF) to 79 % (30 % OSRF). Root acid phosphatase (ACP) and alkaline phosphatase (ALP) activities were generally higher in AMF than non-AMF plants. When compared to NonAMF at 100 % OSRF, AMF plants at 30 % OSRF had higher or comparable ACP and ALP activity, higher leaf elemental P, N, Fe, Cu, and Zn, and a greater PN (at the end of the experiment), leading to generally greater growth parameters with the lower fertility in AMF plants. We suggest that AMF increased nutrient acquisition from an organic fertilizer source by enhancing ACP and ALP activity thus facilitating P acquisition, increasing photosynthesis, and improving plant growth. and L. Amaya-Carpio ... [et al.].
Changes in leaf growth, net photosynthetic rate (PN), incorporation pattern of photosynthetically fixed 14CO2 in leaves 1-4 from top, roots, and rhizome, and in essential oil and curcumin contents were studied in turmeric plants grown in nutrient solution at boron (B) concentrations of 0 and 0.5 g m-3. B deficiency resulted in decrease in leaf area, fresh and dry mass, chlorophyll (Chl) content, and PN and total 14CO2 incorporated at all leaf positions, the maximum effect being in young growing leaves. The incorporation of 14CO2 declined with leaf position being maximal in the youngest leaf. B deficiency resulted in reduced accumulation of sugars, amino acids, and organic acids at all leaf positions. Translocation of the metabolites towards rhizome and roots decreased. In rhizome, the amount of amino acids increased but content of organic acids did not show any change, whereas in roots there was decrease in contents of these metabolites as a result of B deficiency. Photoassimilate partitioning to essential oil in leaf and to curcumin in rhizome decreased. Although the curcumin content of rhizome increased due to B deficiency, the overall rhizome yield and curcumin yield decreased. The influence of B deficiency on leaf area, fresh and dry masses, CO2 exchange rate, oil content, and rhizome and curcumin yields can be ascribed to reduced photosynthate formation and translocation. and Deeksha Dixit, N. K. Srivastava, S. Sharma.
Fifty-d-old poplar (Populus deltoides L.) plants were irrigated with 50-200 mM NaCl. 100 and 200 mM NaCl significantly reduced net photosynthetic rate, chlorophyll and carotenoid contents, leaf area, dry matter accumulation, and harvest index (HI) in all tested poplar clones (Bahar, S7C15, and WSL22). Clone S7C15 was more tolerant to salinity than the other clones. and M. Singh, M. Jain, R. C. Pant.
Radish (Raphanus sativus L.) and carrot (Daucus carota L.), plants with underground storage organs grown in the field, were exposed to either ambient (UVA) or 20 % UV-B (UVE) enhanced solar radiation till their root yield stage. In radish, UVE produced a significant increase in shoot and root fresh mass (FM), increase in the contents of chlorophyll, carotenoids, flavonoids, and total proteins per unit FM, Hill reaction rate, and root yield. In contrast, carrot responded negatively to UVE showing a loss in the above parameters. and S. M. J. Nithia, N. Shanthi, G. Kulandaivelu.
Plants of Brassica juncea L. cv. T-59 were supplied with 50 or 100 µM nickel (Ni50, Ni100) at 10 d after sowing (DAS), and sprayed with 28-homobrassinolide (HBR) at 20 DAS. The plants treated with Ni alone exhibited reduced growth, net photosynthetic rate, content of chlorophyll, and the activities of nitrate reductase (E.C.1.6.6.1) and carbonic anhydrase (E.C. 4.2.1.1) at observed 40 DAS, whereas, the contents of peroxidase (PER), catalase (CAT), and proline were increased. However, the spray of HBR partially neutralized the toxic effect of Ni on most of the parameters. Moreover, the treatment of HBR in association with either of the Ni concentration boosted the contents of PER and CAT in leaves and that of proline both in leaves and roots. and M. Masidur Alam ... [et al.].
Maize plant inbred lines, one Al-sensitive (B-73) and two Al-tolerant (F-2 and L-2039), were grown hydroponically in the presence of 200 µM Al. After 13 d of growth, root and shoot lengths, photosystem 2 (PS2) activity, chlorophyll (Chl) content, 5-aminolevulinic acid (5-ALA) synthesis rate, chlorophyllase (Chlase) activity, and N, Mg, Fe, and Mn contents in leaves were determined. PS2 activity and Chl content were most severely affected by Al in B-73, but F-2 was almost unaffected. This was in accordance with Al-accumulation in the plants. The observed changes in B-73 coincided with 5-ALA synthesis inhibition, Chlase activation, and leaf deprivation of Fe and Mg. In Al-treated L-2039 plants, the leaf Mg and Mn contents were decreased. Also, an excessive Chlase activation was found in Al-treated L-2039, without a substantial Chl loss. This may indicate the activation of different enzyme pools in tolerant and sensitive genotypes under low-stress conditions. and N. Mihailovic, G. Drazic, Z. Vucinic.
The effects of 0, 2.5, 5.0, and 10.0 mg(Cd2+) m-3 [Cd(NO3)2×4 H2O] and 0 and 10.0 mg m-3 gibberellin on certain parameters of photosynthesis and growth in soybean (Glycine max L. cv. Pershing) plants were studied. With increasing Cd2+ concentration in the Hoagland nutrient solution, the contents of chlorophyll and CO2 compensation concentration decreased. The addition of 10 mg m-3 gibberellin reduced the negative effects of Cd2+ in shoot and root growth. With increasing of Cd2+ concentration in the culture medium, the dry matter production in both the roots and shoots decreased as shown by the decline in growth rate (PGR), net assimilation rate (NAR), and leaf area ratio. The addition of gibberellin caused a partial elimination of the Cd effects on the roots and shoots and the PGR and NAR and it increased leaf area and length of stem. and M. Ghorbanli, S. Hadad Kaveh, M. Farzami Sepehr.
We compared the effect of elevated temperature on morphological development, biomass accumulation and allocation, and gas exchange of three dominant plants (Caragana intermedia Kuanget H.C. Fu, Hedysarum mongolicum Turcz., and Artemisia ordosica Krasch.) growing in Chinese Maowusu sandland. Plants were grown in two temperature chambers (25/20, 28/23 °C, day/night) during 60 d. Tree height, number of leaves, and leaf area were increased in C. intermedia and H. mongolicum seedlings, while in A. ordosica temperature only affected tree height. Elevated temperature increased biomass and reduced the root : shoot ratio in C. intermedia and H. mongolicum seedlings, but not in A. ordosica seedlings. The net photosynthetic rate (PN) and transpiration rate (E) were increased at days 40 and 60 in C. intermedia and H. mongolicum seedlings, while in A. ordosica seedlings no significant effects on E were observed, and PN was increased only at day 60. Water use efficiency (WUE) was reduced at days 40 and 60 in H. mongolicum seedlings, and at day 60 in C. intermedia seedlings. No temperature effect on WUE was observed in A. ordosica seedlings. These different responses indicate that climate change could alter plant communities in Maowusu sandland. and Chun-Wang Xiao, Guang-Sheng Zhou, R. Ceulemans.
Responses of baldcypress (Taxodium distichum) seedlings to soil moisture were studied to test the hypothesis that flooding may lead to seedling's higher susceptibility to drought. Treatments included a well-watered but drained control (C), continuously flooded (CF), control followed by drought (CD), and flooded followed by drought (FD). Gas exchange values revealed no significant effects on net photosynthetic rate (PN) in response to flooding. In contrast, after the onset of drought, PN was significantly reduced in CD and FD plants. Significant growth reductions under mild drought conditions indicated that baldcypress seedlings were drought sensitive. However, comparison of gas exchange rates and growth responses between CD and FD plants indicated that prior flooding had no detectable effect on subsequent sensitivity of baldcypress to drought. These findings explain baldcypress persistence in wetland habitats characterized by periodic flooding and mild drought. and J. M. Elcan, S. R. Pezeshki.
With an increase in growth irradiance (from 15 to 100 % of full sunlight, I15 to I100), the maximum net photosynthetic rate (Pmax), compensation (CI) and saturation irradiances of A. annua increased. At full sunlight, A. annua had a high capacity of photosynthesis, while at low irradiance it maintained a relatively high Pmax with a low CI. The height and diameter growth, total and leaf biomass, and artemisinin content of A. annua decreased with the decrease in irradiance, which might be connected with lower photosynthesis at lower than at higher irradiance. Irradiances changed biomass allocations of A. annua. The leaf/total mass ratio of A. annua increased with decreasing irradiance, but the root/total mass ratio and root/above-ground mass generally increased with increasing irradiance. Thus A. annua can grow in both weak and full sunlight. However, high yield of biomass and artemisinin require cultivation in an open habitat with adequate sunshine. and M. L. Wang ... [et al.].