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Item Non-destructive and cost-effective 3D plant growth monitoring system in outdoor conditions : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in School of Food and Advanced Technology at Massey University, Palmerston North, New Zealand(Massey University, 2022) Paturkar, Abhipray P.Plant growth monitoring is one of the crucial steps within plant phenotyping. Traditional manual measurement techniques are error-prone and destructive. In recent times there has been substantial progress in computer vision-based methods. Due to their non-destructive nature and increased accuracy, imaging techniques are becoming state-of-the-art in plant phenotyping. However, most of the associated cameras, sensors, and processors are expensive, resulting in their reduced applicability in this area. This thesis proposes a framework for low-cost plant growth monitoring. A novel, cost-effective and non-destructive 3D method is proposed. It uses a smartphone’s camera and is based on the structure-from-motion algorithm to construct 3D plant models. This algorithm uses several overlapped images to build the model. The modelling speed and quality largely depend on the number of input images used. It is challenging to select the right number of images to generate an accurate plant model - too few images might generate false points in the 3D point cloud, whereas too many images will result in redundant processing, which will inevitably increase computation time. An analytical method is proposed to determine the appropriate number of images for modelling to solve this problem. Once the 3D model is generated, it is essential to segment the various plant components such as leaves and stems to measure traits. The segmentation method needs to be able to work regardless of the particular plant architecture. This thesis proposes a segmentation method using Euclidean distance to segment the point cloud. Finally, plant traits for growth monitoring are measured: leaf length, leaf width, number of leaves, stem height, and leaf area. Methods to accurately measure leaf length, width and stem height when curled are proposed. To conclude, this thesis demonstrated that the proposed framework could monitor plant growth and calculate structure and growth parameters in different outdoor conditions. The framework was tested using five different plants with different architectures: cauliflower, lettuce, tomato, chilli, and maize. Hence, this framework is a potential alternative to costly state-of-the-art systems.Item The distribution of growth in a maize leaf : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Botany at Massey University(Massey University, 1986) Ritchie, Margaret AnnThe extension in a maize leaf phytomer was studied in terms of the one dimensional displacement of its fabric relative to its base as a function of position and of age. The relationship between displacement, position and age was termed the displacement field. The displacements, during a 24 hour interval, of a series of points spaced along the length of a particular phytomer was recorded. This provided an Eulerian evaluation of the 24 hour displacement field. A population of plants each representing a different age were used and the average displacement field of the phytomer during its period of growth was established. Extension was localised in the region named the growth zone at the base of the phytomer. The length of the growth zone rose and fell following a wave shaped curve with respect to age. It was never constant. The relationship between the displacement of and position of points within the growth zone formed a smooth sigmoid curve. The presence of the ligule and of the node of leaf insertion did not give rise to any local reduction in extension. A method of tracing the movement of a point in the leaf fabric, through the growth zone, over a period of time is explained. Such Lagrangian pathlines are described using referential notation, X=x(t;x.). The pathlines of points were constructed by a stepwise addition of the relevant displacement values read from the displacement field for each successive position and age. The pathlines of two chosen points provided positions, as a function of age, for the boundaries of a growing and moving segment. The segment was in mid lamina. Its length increased from 0.025mm when its lower boundary was at 3.6mm from the leaf base to 2mm at maturity. The numbers by types of cells in the lower epidermis of the segment were surveyed at a series of plant ages. There was an initial decrease and then a considerable increase in the average length of the non stomata! cells during the period of the experiment. During the same period the segment increased in length and this was accompanied by an increase in the number of cells in the sample rows. This increase in cell numbers was continuing when the segment reached a position 40mm from the base of the leaf within the then 67mm long growth zone. The associated cell division was occurring in all of the cell categories, not the stomata! complexes alone. The development of stomata with respect to plant age is discussed. Stomata! initiation in the leaf segment was not restricted to a single occasion or unique position in the growth zone.Item A study on the effect of sward conditions on herbage accumulation during winter and spring : a thesis presented in partial fulfilment of the requirements for the degree of Master of Applied Science in Plant Science at Massey University(Massey University, 1999) Hughes, Fulton PaulRecently there has been an increased trend for farmers to adopt farm systems that operate at a reduced stocking rate, with the aim to improve per hectare production through achieving higher production per cow. The emphasis of these farming systems is on improving cow intakes and production and increasing herbage accumulation through the maintenance of pasture conditions with emphasis on pasture quality and higher post grazing residuals. A key issue at the centre of such a grazing system is whether the increase in pasture accumulation will outweigh the decrease in pasture utilisation at the time of grazing, thus increasing overall efficiency. The objectives of this study were to measure the effect of herbage mass present after grazing on subsequent net herbage accumulation rate, and to explain these differences through monitoring changes in sward components, as well as discussing the practical implications of these within a dairy farming system. Two experiments were conducted on a commercial dairy farm near Dannevirke in 1998, Experiment I over winter (June 19 – August 28) and Experiment II in spring (September 18 – October 28). The farm was situated approximately 300m A.S.L. with the soil type being a combination of an Ashhurst stony silt loam and a Dannevirke silt loam, with high soil fertility levels. Treatments involved a range of post-grazing residuals representing cow intake levels from under fed to ad-lib (900, 1200, 1500, 1800, 2100 kg DM/ha in winter and 1200, 1500 1800 2100 kg DM/ha in spring, Treatments 1-5 and 1-4 respectively). The spring experiment also involved nitrogen treatments at rates of 0, 25 and 50 kg N/ha. Heifers and dry cows were used to graze plots with grazing intensities calculated for stock to reach the targeted residuals in 24 hours (Experiment I) and 8 hours (Experiment II). Experiment I was designed as a randomised complete block design, and Experiment II as a randomised split plot design. Both experiments were replicated three times. In both experiments a range of post-grazing residuals was achieved (870, 1140, 1394, 1635, 1917 in Experiment I, and 1098 1424, 1704, 1913 in Experiment II). Post-grazing residuals in both experiments were significantly different (P<0.05). A post-grazing residual of 1394 and 1704 kg DM/ha in winter and spring respectively resulted in the greatest net herbage accumulation rates (16.3 and 81.7 kg DM/ha/day) from grazing until a pre-grazing target level of 2600-2700 kg DM/ha was achieved. Net herbage accumulation rates measured in both experiments were higher than those used in practice on the case farm. No statistical differences existed in Experiment I. In Experiment II Treatment 3 (1704 kg DM/ha residual) was significantly (P<0.05) higher than the other treatments. The relationship between herbage mass and net herbage accumulation rate showed a positive trend in both experiments. The herbage mass at which pasture accumulation was optimised was greater in spring (2900 kg DM/ha) than winter (2500 kg DM/ha). In both Experiments tiller density was greater in more intensely grazed swards, and showed a compensation effect with tiller weight. In Experiment I all treatments increased in tiller density with Treatment 1 having a significantly greater (P<0.05) increase than the other treatments. In Experiment II tiller density in all swards declined over the entire experiment, being greatest (P<0.01) in Treatment 3. Leaf extension rates had a similar trend to tiller weight in Experiment I with the laxer treatments (Treatments 3-5) having a significantly higher (P<0.01) extension rate than Treatments 1 and 2. Treatment 3 also had the fastest leaf appearance rate (17.1 days/leaf), although this was only statistically different to Treatment 5. Leaf appearance rates in Experiment II showed no trend, with Treatments 2 and 4 having the fastest appearance rates, and Treatment 3 the slowest. Tiller appearance rates showed some evidence of a trend (although not significant) with more intensely grazed swards tending to have a slightly faster appearance rate compared to more laxly grazed swards. Tiller weight and leaf extension rate were significantly correlated (P<0.05) to net herbage accumulation in winter. In spring all sward components measured were correlated (P<0.01) to net herbage accumulation with leaf appearance rate being the most significant (P<0.001). Botanical composition in Experiment I showed that more intensely grazed plots had a greater (P<0.05) proportion of leaf, lower proportion of dead material and higher clover content. In Experiment II the trend between variables and grazing level was similar but not significant. The proportion of clover and dead material in spring swards was low (averaging 9.8 and 14.9% respectively) given the herbage mass levels reached. NIR results in general reflected the changes in botanical composition. It was concluded that there is benefit in the use of sward conditions (targets) in the planning and management of grazing systems in enhancing both pasture and animal performance. Compensatory effects between sward components resulted in non-significant differences in herbage accumulation rates, and in practice, differences in pasture growth are likely to occur at extreme grazing residuals. Grazing management decisions are therefore more likely to be based on residual dry matter to achieve desired intakes for high per cow production, high pasture utilisation and high pasture quality, rather than to optimise pasture accumulation. It is recommended that residual herbage mass after grazing should be 1200-1300 kg DM/ha and 1500-1600 kg DM/ha in winter and spring respectively. The practical implications of these are discussed.Item A physiological investigation of the adaptive significance of juvenility in Pennantia corymbosa Forst : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Botany at Massey University(Massey University, 1978) Hollows, David GrantThe responses of the juvenile and adult growth forms of Pennantia corymbosa Forst. to a range of light intensities, leaf temperatures, shoot water potentials and wind velocities were investigated. Results tend to indicate that the small-leafed divaricating juvenile is better adapted to open habitats than the adult. Responses to light intensity were similar for both growth forms. Measurements of photosynthetic rates at various light intensities after pretreatment at low and high irradiances revealed little difference in response between juvenile and adult, with both showing a similar increase in photosynthetic rates and light saturation points after the pretreatment light intensity was increased. Granal stacking in chloroplasts from juvenile and adult leaf palisade was reduced after growth at the higher pretreatment light intensity to the same extent in juveniles and adults. Solarization, despite the presence of a hypodermis, was greater in the adult, while the activity of Ribulose -1,5- diphosphate carboxylase was greater in the juvenile. The indication that the juvenile is better adapted to open habitats is also supported by the results of experiments into the response of photosynthetic rates to a range of temperatures. The data revealed a higher mean temperature optimum for the juvenile than for the adult leaves (21°C c.f. 18°C). The hypothesis that the juvenile might be better adapted to edaphic water stress was tested by withholding water for 14 days and measuring the rates of photosynthesis and transpiration as shoot water potential decreased. Rates of photosynthesis and transpiration declined in both juvenile and adult leaves as shoot water potential decreased. However, the juvenile was able to maintain a higher rate of photosynthesis at comparable low water potentials than the adult which indicates that the juvenile is the more drought tolerant of the two. Leaves of the juvenile also retain water better than those of the adult under moderately windy conditions. When plants were grown in a wind tunnel at wind speeds of up to 12 m secˉ¹ stomatal closure (as measured using a leaf diffusion resistance meter) occurred at lower wind speeds in the juvenile than the adult leaves. The results obtained during this investigation thus support the hypothesis that the small-leafed divaricating juvenile of Pennantia is better adapted to a dry, exposed habitat than is the large-leafed orthotropic adult.Item The development and application of a technique for continuous measurements of plant elongation : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Botany at Massey University(Massey University, 1974) Marshall, David ClarkThe development of an auxanometer capable of detecting 0.67 um increments in plant elongation and its application to the study of hypocotyl elongation in intact Lupinus angustifolius seedlings is described. A displacement transducer, in conjunction with a carrier wave oscillator-demodulator and a digital voltmeter, was utilised to detect changes in length of the elongating hypocotyls of four day old lupin seedlings. The design of a root bathing solution chamber and environmental control chamber is outlined. With the aid of these two chambers the following environmental parameters could be varied independently:- temperature, water potential and aeration of the root bathing solution; temperature, relative humidity, and gaseous composition of the environment; composition and intensity of light within the environmental chamber. Problems encountered in effecting rapid changes of these parameters are discussed. The viability of the auxanometer as an effective tool for plant growth research was tested by its application to the study of growth rates under a variety of environmental changes. Short term growth responses of lupin hypocotyls to changes in relative humidity, root temperature, and osmotic potential of the root bathing solution, plus exposure to anaerobic nitrogen and carbon dioxide atmospheres, have yielded the following results:- 1. Variations in saturation deficits of between 2.9 and 16.2 mbar altered growth rates only marginally. 2. Fluctuations in root temperatures between 23 and 43°C scarcely effect hypocotyl growth rates. 3. Growth responses to changes in osmotic potential of the root bathing solution are similar to those described by Acevedo et al (1971) with intact maize leaves. 4. Periods of anaerobic nitrogen conditions yielded results comparative with those of Gillbank et al (1972), Who studied the effects of cyanide on growth of wheat coleoptile segments, except for nitrogen treatments of more than 30 minutes in duration. 5. Exposure of seedlings to an anaerobic carbon dioxide atmosphere stimulates hypocotyl growth rates by up to eight times, the results indicating that CO2 stimulates the utilisation of a growth precursor within the cell whilst simultaneously inhibiting its synthesis. The results illustrate both the versatility and the potential of the described auxanometer in the description of plant growth responses to environmental changes, consequently aiding in the identification of the causal mechanisms of plant growth processes.Item Aq2 : a highly water-soluble plant growth regulator from the pollen of Pinus radiata : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Chemistry at Massey University(Massey University, 1974) Tse, Phillip GordonAq2; a highly water-soluble plant growth regulator from the pollen of Pinus radiata Aq2 was detected in crude aqueous extracts from the pollen of Pinus radiata by Sweet and Lewis (1971). These workers noted Aq2 possessed some properties of both gibberellins and cytokinin-like compounds and was probably involved in the regulation of pollen tube growth. A further study was under-taken by Gallagherand Aldersley (1972) and these workers concluded after a preliminary investigation that Aq2 was most probably a cytokinin. The purpose of this thesis was to further investigate the nature of Aq2. The physiological role and chemical composition of pollen, with special reference to P. radiata was studied, and a review of plant growth regulators carried out with a view to classifying Aq2 into one of the four groups. A survey of possible isolation techniques was also made. Anion and cation exchange columns were run at various pH's and a portion of the activity attributable to Aq2 was found to bind to an anion column at pH 8.5.The remainder passed straight through the column. An aqueous alcohol treatment has been employed to remove some of the excess carbohydrate material, and freeze drying was shown not to affect the activity of Aq2. Chemical evidence tends to mitigate against Aq2 being a gibberellin; however, the possibility that Aq2 is a cytokinin has not yet been ruled out. No additional physiological studies have been carried out since those of Sweet and Lewis(1971); however, good responses are still obtained in the radish cotyledon assay for cytokinins. If Aq2 is indeed a cytokinin it does not appear to resemble any of those known to date.Item Artificial light spectra and plant growth : a thesis presented in partial fulfilment of the requirements for the degree of Master of Horticultural Science in Plant Science at Massey University(Massey University, 1972) Warrington, Ian JamesThe growth, development and differentiation of plants growing in natural environments is determined by biotic, genetic and physical factors. Within each plant species the absolute limits of any growth response is established by inherent genetic information and the delineation of that response is, in turn, determined by the physiology of the plant. Among the most important physical factors in any natural environment are light quality, quantity and duration. Plant growth depends on a very narrow bandwidth of the electromagnetic spectrum which usually includes the near ultraviolet (down to 320 nm), the visible, and the near infra-red (up to 800 nm) regions. The radiation of this spectral range not only supplies the necessary energy for photosynthesis on which plant metabolism is based, but also by way of various photomorphogenetic processes, it controls, independently of photosynthesis, the way in which this captured energy is directed along the various metabolic pathways. Since for most processes other than photosynthesis, the amount of radiant energy initially absorbed is low, in relation to the response effect, these light reactions can be considered to belong to a group of photostimulus processes which are characterised by dose-effect relationships. These are exothermic in that they ultimately release, or direct an amount of stored energy, which may be very large as compared with the energy content of the radiation initially responsible for the stimulus (Wassink and Stolwijk, 1956).Item 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(Massey University, 2016) Manandhar, SarinaShoot 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.