A coupled model of leaf photosynthesis and stomatal conductance as a function of photosynthetically active radiation (PAR), CO2, leaf temperature, relative humidity, and leaf age was calibrated for rose leaves. The photosynthetic parameters: maximum carboxylation rate (Vcmax), potential rate of electron transport (Jmax), rate of triose phosphate utilization (TPU), and leaf dark respiration rate...

BACKGROUND AND AIMS Photosynthetic thermotolerance (PT) is important for plant survival in tropical and sub-tropical savannas. However, little is known about thermotolerance of tropical and sub-tropical wild plants and its association with leaf phenology and persistence. Longer-lived leaves of savanna plants may experience a higher risk of heat stress. Foliar Ca is related to cell integrity of ...

Tobacco plants (Nicotiana rustica L.) pre-exposed to leaf dehydration, mineral deprivation, salination, or BO(3) (3-) toxicity exhibited increased resistance to subzero temperature and to reduced oxygen in the root medium. The stressed plants all showed an elevated content of leaf abscisic acid. Upon transfer of mineral deprived and salinated plants to prestress conditions, a decline in leaf ab...

The effect of various day temperatures on NADH-nitrate reductase, NADH- and NADPH-glutamate dehydrogenases, nitrate, protein and leaf area, measured at intervals during the ontogeny of the first trifoliolate soybean leaf, was determined. At 32.5 C and 25 C, nitrate concentration, nitrate reductase, and NADPH-glutamate dehydrogenase activities increased concurrently with leaf development and the...

water deficit is an important factor limiting crop production worldwide. drought stress can be managed by improving the availability of soil moisture conserved and selecting drought tolerant genotypes. several physiological indices including stomatal conductance (kl), relative water content (rwc), leaf temperature (tl) and crop temperature stability (cts) along with yield, its components and se...

wheat, cv. alvand, under late sowing condition and comparison with conventional sowing date was investigated in a field experiment in 2009-2010. the factors were seven levels of priming by sa, including control or untreated seeds, 400, 800, 1200, 1600, 2000 and 2400 µm sa and two sowing dates including conventional sowing date (23 october) and late sowing (22 november). results showed that prim...

Recent warming significantly advanced leaf onset in the northern hemisphere. This signal cannot be accurately reproduced by current models parameterized by daily mean temperature (T(mean)). Here using in situ observations of leaf unfolding dates (LUDs) in Europe and the United States, we show that the interannual anomalies of LUD during 1982-2011 are triggered by daytime (Tmax) more than by nig...

Wintering Sasa senanensis, dwarf bamboo, is known to employ deep supercooling as the mechanism of cold hardiness in most of its tissues from leaves to rhizomes. The breakdown of supercooling in leaf blades has been shown to proceed in a random and scattered manner with a small piece of tissue surrounded by longitudinal and transverse veins serving as the unit of freezing. The unique cold hardin...

—Precise estimates of past temperatures are critical for understanding the evolution of organisms and the physical biosphere, and data from continental areas are an indispensable complement to the marine record of stable isotopes. Climate is considered to be a primary selective force on leaf morphology, and two widely used methods exist for estimating past mean annual temperatures from assembla...