This article reviews recent studies from our laboratory on protein regulators of the proteasome (multicatalytic proteasome complex) in red blood cells. A 240-kD inhibitory component (CF-2) exists in 26S proteasome complexes in a form which is conjugated to ubiquitin. Interestingly, this factor was shown to be identical to 8-aminolevulinic acid dehydratase (ALAD), involved in heme synthesis. A distinct 200-kD inhibitor of the proteasome is not present in the 26S complex. A 32-kD subunit of the 20S proteasome appears to be important for the latency of this core protease. Multiple isoelectric variants of the 32-kD subunit are consistent with phosphorylation. Another 20S proteasome subunit of 30 kD molecular weight is phosphorylated at specific serine residues by copurifying casein kinase II. It is suggested that ubiquitination and phosphorylation may account for at least part of the ATP dependency associated with the 26S proteasome complex. These modifications may play a role in the activity, assembly, translocation and/or turnover of this particle.
Heritage trees carry both botanical and historical value for a city’s resilience and sustainability and hence are precious and unique. Their transplant is costly and very rare due to tremendous cost and 100% survival requirement by law. Rootless transplant is even more detrimental to the heritage tree due to removal of roots infected by brown root rot (BRR) before transplanting. This study examined the adventitious roots (AR) induction ability of the Ficus elastica Roxb. heritage tree infected with BRR. The experimental design considered three factors: root diameter (RD), wounding method (WM), and auxin solution on aerial roots under fractional factorial experiment in completely randomized design (CRD). There were four RD groups: RDI (RD < 2 cm), RDII (2 ≤ RD ≤ 4.3 cm), RDIII (4.3 < RD ≤ 22), and RDIV (RD > 22); three WMs: cutting off (CF), girdling (GD), and rectangular shape peeling (RP) of aerial roots; and three auxin solutions: 2000 mg·L−1 IBA(Indole-3-butyric acid) (2B), 2000 mg·L−1 IBA + 2000 mg·L−1 NAA(1-Naphthaleneacetic acid) (2NB), and 4000 mg·L−1 IBA (4B) plus water as control (C). The number of rooting wounds, number of roots, and the mean length of the three longest adventitious roots in each wound were recorded to evaluate the AR rooting performance. Twenty four treatment combinations including 328 wounds were tested. The results showed that rooting ability was significantly correlated with RD and WM. Smaller RDs had better rooting and declined with increased RDs. CF had the best rooting followed by GD and then RP. Auxin solution did not significantly affect the rooting ability. It may be due to the abundant endogenous auxin in the heritage tree, which mitigated the effect of exogenous auxin for AR induction. We conclude that cutting off small-diameter aerial roots is the best approach to induce ARs from rootless F. elastica heritage trees to enhance transplantation success.
We evaluated the effect of water and ethephon (2-chloroethyl phosphonic acid) under different doses (500 mg.L−1, 1000 mg.L−1, 2000 mg.L−1, and 3000 mg.L−1), with and without calcium acetate (CA) in two foliar applications on camphor and golden shower saplings. It was aimed for ethephon to replace pruning in reducing transpiration during transplantation. We adopted a completely randomized design as an experimental design. An adequate dose of the ethephon/CA solution must be able to defoliate more than 50% of the foliage and recover to more than 75% of the foliage between 11 May and 19 July. The result showed that defoliation started within one week of the first spray, reached the lowest foliage retention rates (LRRs) in one month, then re-foliated. The LRRs were correlated with the doses of ethephon in the means, but most of the treatments did not show statistical significance due to the large in-group variations among replicates. Adding CA raised the LRRs and alleviated the dieback, especially on camphor trees. Adding CA was necessary for camphor trees to re-foliate. The final foliage retention rate (FRR) was influenced by the ethephon dose, and different tree species showed different restoration abilities. The adequate dose for camphor and golden shower trees to have an LRR < 50% and an FRR > 75% was to spray 1000 mg.L−1 of ethephon first, then spray another 2000 mg.L−1 of ethephon and 8000 mg.L−1 of CA three days later.
When transplanting mature Ficus trees, the large root balls are expensive to treat, handle, and move. This study aimed to identify the optimal wounding method and auxin treatment for regenerating adventitious roots (ARs) from weeping fig (Ficus benjamina L.) stems to uptake additional water and to compensate for fewer absorption roots in the smaller root balls at transplantation. We adopted a two-factorial experiment involving the wounding methods (three-line cut (3LC) and rectangular peel (RP)) and auxin treatments (2000 mg·L−1 Indole-3-butyric acid (IBA), 2000 mg·L−1 IBA + 2000 mg·L−1 1-naphthaleneacetic acid (NAA), and 4000 mg·L−1 IBA). The rooting rate of each treatment, the mean root number, the length of the three longest ARs, and the dry weight of ARs in each wound were evaluated. The treatment combination using 4000 mg·L−1 IBA with RP13 (rectangular peel 1/3 the perimeter of the stem) consistently exhibited the best rooting results in 2019 and 2020. It had a 100% rooting rate, a mean of 18.5 roots, a 16.8 cm root length, and a 1640 mg dry weight in the wounds. All auxin treatments demonstrated a superior rooting ability as compared to water treatments. The RP method regenerated more roots than the 3LC method. Doubling the RP length to be 2/3 of the perimeter improved the rooting ability. The locations of ARs varied under different treatment combinations, with 4000 mg·L−1 IBA on RP13 demonstrating the most diversified distribution on four edges of the wounds. Thus, it is recommended to regenerate ARs from stems of F. benjamina trees.
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