ABSTRACT
Successive single day transfers of pot-grown wheat to high temperature (35/30°C day/night) replicated controlled environments, from the second node detectable to the milky-ripe growth stages, provides the strongest available evidence that the fertility of wheat can be highly vulnerable to heat stress during two discrete peak periods of susceptibility: early booting [decimal growth stage (GS) 41-45] and early anthesis (GS 61-65). A double Gaussian fitted simultaneously to grain number and weight data from two contrasting elite lines (Renesansa, listed in Serbia, Ppd-D1a, Rht8; Savannah, listed in UK, Ppd-D1b, Rht-D1b) identified peak periods of main stem susceptibility centered on 3 (s.e. = 0.82) and 18 (s.e. = 0.55) days (mean daily temperature = 14.3°C) pre-GS 65 for both cultivars. Severity of effect depended on genotype, growth stage and their interaction: grain set relative to that achieved at 20/15°C dropped below 80% for Savannah at booting and Renesansa at anthesis. Savannah was relatively tolerant to heat stress at anthesis. A further experiment including 62 lines of the mapping, doubled-haploid progeny of Renesansa × Savannah found tolerance at anthesis to be associated with Ppd-D1b, Rht-D1b, and a QTL from Renesansa on chromosome 2A. None of the relevant markers were associated with tolerance during booting. Rht8 was never associated with heat stress tolerance, a lack of effect confirmed in a further experiment where Rht8 was included in a comparison of near isogenic lines in a cv. Paragon background. Some compensatory increases in mean grain weight were observed, but only when stress was applied during booting and only where Ppd-D1a was absent.
ABSTRACT
The waiting list for renal transplantation has grown at an alarming rate over the last 2 decades, resulting in increased waiting times and deaths on the waiting list. To increase the number of available organs for transplantation, aggressive public education programs have been developed. The federal government has strengthened hospital regulations ensuring referral of all potential donors to organ recovery agencies, and living donor programs no longer limit donation to genetically related donors and recipients. We present a case that illustrates the complex ethical issues that are integral to the field of transplantation and the allocation of a scarce resource: a 50-year-old man who has a daughter with end-stage renal disease has suffered a severe cerebral vascular accident but is neither brain-dead nor a candidate for "non-heart-beating" donation. Given his poor prognosis, should the father be able to donate his kidney to the daughter in his compromised condition?
