The Effect of Sugar on Bean Plant Growth

The Effect of Sugar on Bean Plant Growth

ABSTRACT

This project was to determine if bean plants grew stronger and healthier by the addition of the right amount of sugar to their watering. It is believed that plants that receive 50 grams of sugar per liter of water would help bean plants grow to be stronger, healthier and larger because they would get energy from the sugar. In order to investigate the effects of different irrigation regimes on growth and grain yield of three faba bean cultivars, a split-plot experiment (using RCB design) with three replications was conducted in Ahmadu Bello University. Irrigation regimes (I1, I2 and I3: irrigation after 70, 100 and 130 mm evaporation from Class A pan, respectively) and faba bean cultivars (Aquodolce, Barakat and Saraziri) were allocated to main and sub plots, respectively. The results of plant growth analysis on the basis of growing degree-days (GDD) revealed that dry matter accumulation (DMA), crop growth rate (CGR) and relative growth rate (RGR) were reduced due to water deficit. Water limitation also reduced grains per plant, grain filling duration and grain weight. Consequently, grain yield per unit area under limited irrigation was considerably lower than that under well-watering. ‘Barakat’ had the highest DMA, CGR, grain filling duration and grain yield per unit area. Barakat was a superior cultivar under both well and limited irrigation conditions, compared with Aquodolce and Saraziri. This superiority was attributed to the production of larger and more grains per plant under all irrigation treatments. It was concluded that faba bean is a sensitive crop to water deficit and therefore sufficient suger water supply during vegetative and reproductive stages is required to ensure a satisfactory yield achievement.

CHAPTER ONE

INTRODUCTION

1.1 Background of the Study

Sugar water stress affects practically every aspect of plant growth and metabolism. Plant responses to sugar water deficit depend upon various factors such as duration and degree of stress, growth stage and time of stress exposure (Gupta and Sheoran, 1983). Due to their sedentary mode of life, plants resort to many adaptive strategies in response to different abiotic stresses such as high salt, dehydration, cold and heat, which ultimately affect the plant growth and productivity (Gill et al., 2003). Against these stresses, plants adapt themselves by different mechanisms including change in morphological and developmental pattern as well as physiological and biochemical responses (Bohnert et al., 1995). Adaptation to all these stresses is associated with metabolic adjustments that lead to the modulation of different enzymes (Shinozaki and Shinozaki, 1996; Yan et al., 2001; Ehsanpour and Amini, 2003). Among these enzymes are phosphatases, which are believed to be important for many physiological processes, including regulation of soluble phosphorous (Pi) (Yan et al., 2001). Phosphateases are traditionally classified as being acid and alkaline depending on their optimum pH for enzyme activity, above and below pH 7.0 (Barret-Lennard et al., 1982). Free soluble phosphate reserves plays vital role in energy transfer, metabolic regulation, important structural constituent of biomolecules like phytin bodies in the ungerminated seeds, protein and nucleotide phosphoryla- tion (Fincher 1989; Ehsanpour and Amini, 2003).
Although, some abiotic stresses like salt, osmotic and sugar water have been reported to increase phosphatase activities by maintaining a certain level of inorganic phosphate in plant cells (Olmos and Hellin, 1997), the exact role of phosphatases in the germinated seeds is still not clear, because metabolism of these compounds can be affected by a number of environmental factors such as stress type, irridance, temperature, and type of ions present (Bohnert et al., 1995). Germination of grains is initiated by sugar water uptake and its successful completion is signaled by emergence of the developing root and shoot. Following uptake of water, hormone signals, probably released from the emergence, are believed to result in the synthesis of hydrolytic and other enzymes in the endosperm (Fincher, 1989). Moreover, like mature plants, germinating seeds and seedlings also can be subjected to environmental stresses. Even when they imbibe water, seeds may be exposed to elements of a hostile environment, which include high temperature of soil, salinity and varying moisture content. Failure to cope with the adversity cause by these extremes results in poor germination, seedling development, and eventually, reduced crop yields.

The variation that occurs in phosphatase activities during germination is poorly understood and information on physiological events involved in this process is scarce. Therefore, in this study, we present details on germination, growth and status of phosphatase enzyme activities in germinating sorghum seeds under salt, drought stresses and to the application of ABA and GA3. Sorghum is a C4 grass that is well adapted to semiarid and arid tropics (Quinby, 1974) where salinity is the major problem due to limited sugar water supply. This grain crop is the fifth most important cereal grown worldwide, due in large parts to its unusual tolerance to adverse environmental conditions (Doggett, 1988). ABA and GA3 are well-documented regulators of germination, with GA generally having promotive effects and ABA having inhibitory effects on germination and related changes through multiple regulatory mechanisms, including transcriptional control and synthesis of specific enzymes (for review see Fincher, 1989).

1.2 Statement of Problem

The vital needs of a plant are very much like our own – light, water, air, nutrients, and a proper temperature. The relative importance of each of these needs differs widely among plants. The ability of a plant species to spread throughout a geographic area is a direct result of its adaption to the abiotic and biotic components of the area. Although most habitat components act on a plant simultaneously and should be considered together, the lack of one essential component can determine the health of a plant. This factor, whatever it may be, is referred to as a limiting factor. The concept of limiting factors applies to all aspects of a plant’s interaction with its habitat. Any factor in the ecosystem can act as a limiting factor. For example, sugar water is important to many species; most species cannot live in desert regions because of lack of sugar water and most cannot live in marshes because of excess water. Extreme temperatures inhibit plant growth in many regions; lack of warmth in winter is a limiting factor that keeps many species restricted to the tropics. Another limiting factor is often competition from species that use the same resources. Competition is the principal interaction among plants. Plants of the same species are strongly competitive because they have the same requirements for sunlight, water, and nutrients. This study seeks to investigate the effect of sugar on bean plant growth.

1.3 Objective of the Study

The main objective of this study was to investigate the effect of sugar on bean plant growth.