Strigolactones and hormonal interaction in control of branching in Zantedeschia and other horticultural species : a thesis presented in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Plant Science at Massey University, Palmerston North, New Zealand

Shoot branching that involves development of lateral buds into shoots is one of the important factors influencing crop productivity. Strigolactones have recently been found to be involved in the control of branching, but the actual bioactive compound/s that inhibits bud outgrowth is still unknown. A germination assay utilizing the seeds of a parasitic weed (Orobanche minor), detected strigolactones within the xylem exudates of different horticultural crop species; the strigolactone concentration negatively correlated with branching of cultivars or mutants. In Zantedeschia grown in vivo, the concentration of strigolactones was independent on the volume of guttation fluid (xylem exudates) suggesting the difference in concentration of strigolactones in high and low branched cultivars was due to the difference in potential of producing strigolactones between these cultivars and not due to differences in volume of guttation fluid. While identifying a bioactive compound using germination and branching assays in combination with liquid chromatography and mass spectrometry, compounds containing „N? were detected in the low branched wild-type Petunia, but not in the highly branched mutant, suggesting the possibility of such compounds being SL-conjugates which may be associated with bud outgrowth inhibition. In Zantedeshia (in vitro) and pea stems, strigolactone reduced the axillary shoot number stimulated by the cytokinin suggesting an antagonistic interaction between these two hormones on bud release. However, as cytokinin may stimulate subsequent growth of released buds by increasing the auxin transport out of the bud, strigolactone may have reduced subsequent growth by reducing auxin transport. Since GA3 enhanced subsequent growth of buds in pea stems, but not the release, an antagonistic interaction between strigolactone and gibberellins on subsequent growth is possible. Interestingly, strigolactone successfully reduced adventitious bud formation in Zantedeschia grown in vitro, adding a new role for strigolactones in plant development. Despite correlation between strigolactone and branching inhibition in different horticultural crops such as apple, kiwifruit, Zantedeschia and Acer, further studies relating to strigolactone and its interaction with other hormones on branching of these crops could be performed using in vitro techniques for a clear understanding of strigolactones? role on branching inhibition. More importantly, quantification of strigolactones using the germination assay may have significant implications in horticultural crop breeding for obtaining desired shoot branching

Effects of therapeutants and temperature on pollen germination, pollen tube growth and fruit set in fruit crops : a thesis presented in partial fulfilment of the requirements for the degree of Master of Horticultural Science at Massey University

This study involved assessments of therapeutant effects on pollination and fruit set; of temperature effects on pollen germination and pollen tube growth in apples, peaches and kiwifruits; of flowerage effects on pollen germination and pollen tube growth in kiwifruit styles; and of hand pollination effects on fruit set, fruit weight and seed numbers per fruit in kiwifruit vines. From the point of view of their in vitro effects on pollen germination therapeutants can be listed in order of decreasing inhibitory effect as follows: (a) for apples - mancozeb plus dinocap, triforine, dichlofluanid, bupirimate, bayleton, citowett R captan and mancozeb; (b) for peaches - triforine, vinclozoline, streptomycin plus triforine, mancozeb, captafol, iprodione, dichlofluanid, streptomycin and benomyl; and (c) for kiwifruits - dichlofluanid, captan and vinclozoline. However, it appeared that while in vitro a therapeutant was very inhibitory, the application of a spray to anthers in an intact flower did not affect the germination of pollen subsequently released by those anthers. Fungicides proven to be toxic to pollen in vitro did not necessarily produce similarly toxic effects in vivo. Reasons for such varying effects of fungicides on pollen germination and pollen tube growth in vitro and in vivo are suggested. At 24 hours after pollination the number of pollen tubes growing more than 1/2 the style length of kiwifruit (Hayward) flowers one to two days old were 38% and 27% higher than in flowers less than one day old and more than three days old respectively. In apples 5 sprays of either bayleton or captan, 3 sprays of either of the therapeutants mancozeb, mancozeb plus dinocap, and triforine and a wetting agent citowett R applied during bloom period caused no effect in fruit set in Golden Delicious trees; and 3 bupirimate sprays during bloom period had no effect on the fruit set in Splendour trees. In peaches 6 sprays of either captafol, or benomyl or iprodione, 5 sprays of either mancozeb or vinclozoline or streptomycin or triforine during bloom period caused no effect on fruit set in Golden Queen trees. Three sprays of streptomycin or dichlofluanid caused no effect but 3 sprays of triforine, triforine plus streptomycin or of ethephon caused 50%, 70% and 90% reduction in fruit set in Red Haven peach trees. In kiwifruits 3 sprays of either dichlofluanid, captan or vinclozoline reduced seed numbers per fruit by 37% but did not affect fruit set or fruit weight. Thus in vitro and in vivo studies were useful in determining therapeutant effects on pollen but did not necessarily provide information on their effects on fruit set in apple, peach and kiwifruit and on fruit weight and seed numbers per fruit in kiwifruit. The germination of both apple and peach pollen was higher at 24°C than at 16°C, 20°C, 28°C and at 32°C. After 18 hours incubation pollen tubes were longer at 28°C and at 32°C than at 16°C, 20°C and 24°C. In vivo studies with kiwifruit (Matua) pollen showed that pollen germination at 14°C, 18°C, 22°C and 26°C did not differ significantly. Temperatures both higher and lower than the temperature range 18 to 22°C were found to be inhibitory to pollen tube growth in kiwifruit (Hayward) styles. Hand pollination of flowers did not influence percentage fruit set but increased fruit weight and seed numbers per fruit in kiwifruit (Hayward) vines. Because fruit weight was positively correlated with seed number per fruit in fruits from both bee pollinated and bee plus hand pollinated flower clusters, supplementary pollination may play an important role in the production of fruit in kiwifruit orchards

Efficacy of intravenous Tramadol in prevention of catheter-related bladder discomfort in upper urinary tract surgery

Introductions: Catheter-related bladder discomfort (CRBD) is common in patients with urinary catheterization. Centrally acting intravenous opioid like Tramadol inhibits detrusor activity and incidence of CRBD. Present study aims to analyze efficacy of intravenous (IV) Tramadol in prevention of CRBD in patients undergoing upper urinary tract surgery. Methods: Adult patients undergoing elective open upper urinary tract surgeries at Bir Hospital, National Academy of Medical Sciences (NAMS), Nepal, over a period of six months, requiring urinary catheterization were randomly divided into Control (C) and Tramadol (T) groups. After general anesthesia, patients in T-group received IV Tramadol 1.0 mg/kg and C-group received normal saline 30 minutes before extubation. In post-operative ward, CRBD was graded as mild, moderate or severe at 0, 1, 2 and 6 hours. Post-operative Ramsay sedation score and nausea vomiting were compared in two groups.  Results: There were total 70 patients, 35 in each of groups-T and C. Incidence of CRBD in T-group was significantly low compared to the C-group at all points of evaluation (p<0.05). Postoperative sedation score, analgesic requirement and nausea vomiting were not significantly different in two groups. Conclusions: Intravenous Tramadol administered before extubation in upper urinary tract surgery reduces the incidence of CRBD. Keywords: catheter related bladder discomfort (CRBD), detrusor activity, tramado