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In order to evaluate the effect of Glomus versiforme fungus on genes and metabolites related to the biosynthetic pathway of polyamines in pot marigold under drought stress, an experiment was conducted at three irrigation levels [100, 65, and 35% of field capacity (FC)] for 1, 2, 4, and 8 d in mycorrhizal (M) and non-mycorrhizal (NM) plants. At both 35 and 65% FC, putrescine (Put) accumulation peaked at 1 d. Accompanying the accumulation of Put at 1 d, there was an increase in the expression of ARG and ODC genes directly involved in the Put biosynthetic pathway, as well as the ADC, AIH, and CPA genes involved in the indirect Put biosynthetic pathway. At 1 d, M plants induced the accumulation of Put and increased the expression of ADC, AIH, and CPA, but had no significant effect on ODC expression. At both 35 and 65% FC, SAMDC gene expression increased from 1 to 8 d, and the expression of this gene was higher in M plants from 2 to 8 d. At both drought levels, highest Spd content and SPDS gene expression were observed at 2 d. Moreover, Spd accumulation from 2 to 8 d and SPDS gene expression from 4 to 8 d were higher in M plants than in NM plants. At both drought levels, Spm content and SPMS gene expression increased between 4 and 8 d, during which the accumulation and expression level of this gene in M plants was higher. [ABSTRACT FROM AUTHOR]

In order to study the effects of drought at different days on biochemical characteristics of two rose species, a factorial experiment based on randomized complete design with three replications was conducted. Two rose species (damask rose and dog rose) were irrigated at three levels (25, 50 and 100% field capacity, FC) at 1, 3, 6 and 12 days. The results showed that content of amino acids (except tryptophan and histidine) increased at 50 and 25% FC from 1 to 12 days in both species. In 50 and 25% FC treatments relative water content decreased and ion leakage increased from 1 to 12 days in both species. Biomarkers of hydrogen peroxide and malondialdehyde increased from 1 to 12 days in both species at both drought levels. Furthermore, the antioxidant enzyme activity of catalase, peroxidase and superoxide dismutase was enhanced in both species from 1 to 12 days in 50 and 25% FC treatments. Chlorophyll content increased at both drought levels from 1 to 12 days in both species. The content of amino acids and the antioxidant enzyme activity in damask rose was higher than dog rose, while the accumulation of malondialdehyde, hydrogen peroxide, ion leakage and chlorophyll content in dog rose was higher than damask rose under drought stress. [ABSTRACT FROM AUTHOR]

Drought and light are two major factors limiting the growth of cool-season turfgrasses in many areas. The main objective of the present study was to investigate the effects of both irrigation levels and light duration on growth and quality of tall fescue. In order to, a greenhouse experiment was conducted to evaluate the interaction of photoperiod and irrigation on Festuca arundinacea Schreb. at the Research Greenhouse of the Department of Horticultural Sciences, College of Agriculture, Shiraz University, Shiraz, Iran. The experiment was conducted with four field capacity regimes (25%, 50%, 75% and 100%) and three light durations (8, 12 and 16 h) in a completely randomized design factorial arrangements with four replications. Results showed that decreasing field capacity and photoperiod decreased fresh and dry weights of shoot and root, chlorophyll contents and superoxide dismutase, catalase and ascorbate peroxidase activities. Decreasing the field capacity increased proline content and peroxidase enzyme activity. In overall, results showed that, the increase in day lengths alleviates the destructive effects of reduced irrigation and vice versa. [ABSTRACT FROM AUTHOR]