important role in ameliorating heat stress and water stress by reducing solar radiation, and as a result reducing leaf temperature and leaf transpiration through a decrease in evaporative demand between leaves and the surrounding air. Postharvest fruit
temperature fluctuations, this capacity might not keep pace with global warming, reduced ornamental value, and economic losses ( Tao et al., 2015 ). Heat stress not only affects the phenotype of a plant, causing leaf etiolation and wilting, but it alters the
heat stress, has been described as an important limiting factor of turfgrass growth ( DaCosta and Huang 2013 ). The first changes in plants occur at the cellular level and include altered protein and biochemical syntheses, altered metabolism, and
-adapted cultivars, the sale of garden roses has decreased 25% to 30% during the past 20 years ( Byrne et al., 2010 ; Hutton, 2012 ; Pemberton and Karlik, 2015 ). High temperature or heat stress is one of the major limiting abiotic factors for plant growth
, ultradwarf bermudagrass experiences quality decline because of disease and heat stress, especially in the southern part of the United States and other regions with similar climates ( Unruh and Davis, 2001 ). Ultradwarf bermudagrass canopy temperatures during
induced by shade or heat stress was examined, and leaf senescence and CK production associated with ipt gene expression were evaluated. Materials and Methods Tissue culture and plant regeneration. Stolons of creeping bentgrass (cv
, 2004 ; Pessarakli, 2007 ). Drought and heat stress injury are typically characterized by leaf dehydration, reflected as a decline in leaf water content or accelerated leaf senescence due to loss of chlorophyll and photosynthetic activities, as well as
Abstract
Root-zone temperature (RZT) of 15 landscape planting sites in a metropolitan area was monitored from 13 June to 5 Sept. 1985. RZT was highest at urban sites associated with city surface materials, such as asphalt and concrete. The RZT was significantly lower at suburban and woodland sites. Temperature was uniform throughout the root zone at sites along urban streets; it decreased with increasing depth at all other sites. High temperature extremes may contribute to the decline of landscape plants at urban sites.
Abstract
Most systems used for controlling rootzone temperature (RZT) involve grouping plants in each treatment together in one temperature-controlling apparatus (3, 5). The power of experiments using systems with grouped plants is limited because the groups constitute single experimental units during data analysis. Some systems have overcome this problem, but reports may lack fabrication details (2) or indicate a limited RZT range was used (1, 4). We designed a precise, inexpensive system capable of achieving a wide range of RZT in which individual plants are discrete experimental units.
Growth and topological indices of `Eureka' lemon were measured after 6 months in well-watered and well-fertilized conditions and factorial combinations of moderate (29/21C day/night) or high (42/32C day/night) temperatures and ambient (350 to 380 μmol·mol) or elevated (constant 680 μmol·mol-1) CO2. In high temperatures, plants were smaller and had higher levels of leaf chlorophyll a than in moderate temperatures. Moreover, plants in high temperatures and elevated CO2 had about 15 % higher levels of leaf chlorophyll a than those in high temperatures and ambient CO2. In high temperatures, plant growth in elevated CO2 was about 87% more than in ambient CO2. Thus, high CO2 reduced the negative effect of high temperature on shoot growth. In moderate temperatures, plant growth in elevated CO2 was only about 21% more than in ambient CO2. Irrespective of temperature treatments, shoot branch architecture in elevated CO2 was more hierarchical than those in ambient CO2. Specific shoot extension, a topological measure of branch frequency, was not affected by elevated CO2 in moderate temperatures, but was increased by elevated CO2 enrichment in high temperatures-an indication of decreased branch frequency and increased apical dominance. In moderate temperatures, plants in elevated CO2 had fibrous root branch patterns that were less hierarchical than at ambient CO2. The lengths of exterior and interior fibrous roots between branch points and the length of second-degree adventitious lateral branches were increased >50% by high temperatures compared with moderate temperatures. Root length between branch points was not affected by CO2 levels.