Days post anthesis

Capsaicinoids start to accumulate 20 days post anthesis and synthesis usually persists through Suit development [59, 62,73], The site of synthesis and accumulation of the capsaicinoids is the epidermal cells of the placenta in the fmit (Fig. 8.5) [60, 72, 73], Ultimately, the capsaicinoids are secreted extracellularly into receptacles between the cuticle layer and the epidermal layer of the placenta [74]. These receptacles of accumulated capsaicinoids are macroscopically visible as pale yellow to orange droplets or blisters on the placenta of many chile types (Fig. 8.5). 

In this respect, McCue et al.260 showed that cDNAs encoding BEI and BEII of wheat (Triticum aestivum cv Cheyenne) shared extensive identity with BE sequences reported for other plants. Using the cDNAs, they studied the steady-state RNA levels of the branching enzymes during development. For BE2, its RNA was detectable five days post-anthesis (DPA) and reached a maximum at 10 DPA. BEI steady-state levels started rising at 10 DPA, peaking at 15 DPA. Levels of all messages declined at 20-25 DPA. 

Gibberellins in developing fruit are concentrated in the seeds, in which there are two phases of GA production [144], The first phase occurs before there is substantial growth of the embryo. In pea seeds, the concentrations of GA, and GA3 peak at about 4-7 days after anthesis and then decline [4]. There is a second sharp increase in GA production occurring in the pea embryo from about 12 days post anthesis to yield primarily GAjo-Genetic evidence indicates that the first phase of GA production is necessary for seed... 

FIGURE 9.34 OH-3/OH-2 distribution ratios for cotton fibers as a function of days post-anthesis (DPA). 

During the later stages of maturation (ca. 30-50 days post anthesis) grain a-amylase values fall to relatively low levels (20-25 mU/grain). This reduction has been shown to be greater in the case of Rht 1 and Rht 3 where final enzyme levels can be around %th of those in wild-type seeds [6]. 

Viviparous mutants of maize provide a second example of an ABA deficiency during grain development affecting germinability. Precocious germination is observed in the viviparous mutants which are deficient in ABA [7,25]. ABA levels in developing maize have also been reduced by treatment of the embryonic tissue with fluridone, which blocks the synthesis of the carotenoid precursors of ABA. The lack of ABA synthesis may explain why fluridone treatment of embryonic tissue between 9 and 13 days post-anthesis inhibited induction of dormancy [7, 20]. 

Fig. 1. (+ )ABA levels in Brevor embryos during grain development at 25°C upper) or at 15 C lower). The arrow indicates the time that final dw was reached. DPA Days post-anthesis . Data are the means ( SD) of three replicate extractions...

Figure 10.3. SEM images of cotton seed surface at the beginning of elongation of fiber cells in one and two days post anthesis. (Hsieh, Y.L., in Cotton Science and Technology, editors Gordon, S., et al., Woodhead Publishing Limited, 2007.)...

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