Browsing by Author "Mornya, Philip Maada Pessima"

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Chronological changes in plant hormone and sugar contents in cv. Ao-Shuang autumn flowering tree peony
(Ústav zemědělských a potravinářských informací, 2011-09-30) Mornya, Philip Maada Pessima
Successive secondary flowering is critical for tree peony industry. Varying the levels of hormones and sugars are reported to influence plant flowering. This study analyses quantitative changes in the levels of endogenous hormones \[indole-3-acetic acid (IAA), abscisic acid (ABA) and gibberellic acid (GA3)\] and carbohydrates (sucrose, reducing sugar and starch) in the buds of cv. Ao-Shuang tree peony during autumn and spring flowering seasons. The study shows different levels of hormones (ABA, IAA and GA3) and carbohydrates (sucrose, reducing sugar and starch) in spring (SFB) and autumn (AFB) flowering buds. Not only is there increase in IAA, GA3, sucrose and reducing sugar, but also decrease in ABA and starch during AFB developmental stages. This probably contributes to induced flowering in AFB. Compared with SFB, IAA could be a vital AFB flowering hormone because it peaks at three critical bud developmental stages of bud swelling, shoot elongation and flower bud opening. Whereas sucrose and reducing sugar contents increase in AFB, that of starch decreases. SFB shows similar trends for sucrose, reducing sugar and starch. The findings suggest that cv. Ao-Shuang tree peony blooms in autumn probably due to lack of dormancy, a phenomenon induced by low ABA. Thus flowering of tree peonies in SFB and AFB could be regulated by different combinations of hormonal and sugar signals.
Effect of Combined Chilling and GA3 Treatment on Bud Abortion in Forced ‘Luoyanghong’ Tree Peony (Paeonia suffruticosa Andr.)
(KeAi, 2018-09-27) Mornya, Philip Maada Pessima
This research investigated the effect of combined chilling and GA3 treatment on bud abortion of tree peony under greenhouse conditions to determine the dynamics of exogenous hormones and chilling effects on bud abortion. Research of such nature will increase the understanding of the effects of GA3 and chilling level on flower development thereby, promoting off-season cultivation techniques in tree peonies to increase production that meets market demand. Hormone and sugar levels in the ‘Luoyanghong’ tree peony were respectively determined using High-Performance Liquid Chromatography (HPLC) and spectrophotometer. Non-potted chilling with 200 mg·L−1 GA3 treatment reduced bud abortion rate. Flowering rate in non-potted chilling with 200 mg·L−1 GA3 plants was 58%, as against 21% in potted chilling plants with 200 mg·L−1 GA3 treatment. Sugar accumulation in retained or aborted flower buds was conversely related to ABA level. Low ABA and high sugar levels were noted in retained buds whereas the reverse induced bud abortion. ABA level apparently inhibited sucrose and reducing sugar uptake in aborted buds whereas GA3 enhanced sucrose uptake in retained buds. GA3 and IAA levels were higher in retained than in aborted buds, which made plants with retained bud more competitive in nutrient uptake (by root) for growth and development. Overall, combined chilling and GA3 treatment enhanced plant growth and development, particularly bud sprouting, growth and flowering.
Growth and yield response of Okra to method and time of poultry manure application under rain-fed conditions
(University of Ibadan, 2022-10-18) Mornya, Philip Maada Pessima
Matching nutrient demand with supply is critical for plant growth, development and yield. This study investigated the growth and yield response of Okra (Abelmoscus esculentus) to the method and time of poultry manure application, in order to match the time of optimum nutrient release with nutrient uptake by the okra plants. A randomized complete block design with 6 treatments and 3 replicates was used for this study. The poultry manure was applied at three different times: During planting (0-DOP), 2 weeks after planting (2-WAP) and 4 weeks after planting (4-WAP) using two application methods: surface-broadcasting and plow-incorporation. Results showed significant differences in method and time of application of poultry manure. The application of poultry manure, using plow-incorporation method on the day of planting (0-DOPI), significantly improved growth and yield (5.88 t ha-1) of okra. Also, 0-DOPI treatment took fewer days to attain 50% flowering (55 days) and fruit setting (58 days). This indicated that the match between nutrient demand and supply was most evident under 0-DOPI treatment. However, the surface broadcasting method at 2-WAP and 4-WAP, could not match release and supply of nutrients with critical developmental stages of okra. Hence, poultry manure incorporation at time of planting could improve okra production in the study area.
Seasonal changes in endogenous hormone and sugar contents during bud dormancy in tree peony
(2013-12-15) Mornya, Philip Maada Pessima
The trial to investigate hormonal and sugar changes in tree peony buds associated with dormancy was conducted in the field at the Beijing Forestry University Experimental Site in China during autumn, winter and spring seasons (2009/2010 and 2010/2011), the periods of dormancy development and release. The experimental design was randomized complete block with three replications. The hormone and sugar levels were determined using the enzyme-linked immunosorbent assay (ELISA) technique and spectrophotometer, respectively. Winter temperature accumulated abscisic acid (ABA) and sugars in tree peony buds which most likely induced dormancy. Spring temperature, on the other hand, degraded ABA and sugars, and accumulated gibberellic acid (GA3) that possibly released dormancy in tree peony buds indicating that environmental temperature was the key regulator of hormone and sugar levels that influenced bud dormancy and growth. The results suggest that accumulation of ABA, GA3 and sugars in buds during dormancy or bud-break stage appears to be directly related to the degree of temperature experienced at that stage. While ABA and sugar accumulated with decreasing temperature, GA3 accumulated with increasing temperature. It is likely that the reduction of ABA and sugars played an important role in bud dormancy release or alteration in bud growth of tree peonies. Seasonal patterns of sucrose and starch were almost the same in buds of the tested tree peony cultivars which contradicts previous studies suggesting converse relationship in terms of accumulation in winter. However, seasonal accumulation of endogenous compositions varies with cultivar. Among the investigated cultivars, ?Luoyang Hong? (LH) not only accumulated less ABA, GA3 and sugars but also released bud dormancy earlier than the ?Zhao Fen? (ZF) and ?High Noon? (HN), suggesting that the level of these internal compositions in LH is less responsive to seasonal temperature change. The ability of buds to simultaneously accumulate ABA and sugar reserves while in dormant state may provide a significant adaptive advantage for peonies to survive the erratic climate, particularly in temperate regions, which could be one of the reasons for the geographically widespread of the genus Paeonia in the world.