Alocasia Macrorrhiza Research Articles

Gas Exchange Analysis of the Fast Phase of Photosynthetic Induction in Alocasia macrorrhiza

When leaves of Alocasia macrorrhiza that had been preconditioned in 10 micromoles photons per square meter per second for at least 2 hours were suddenly exposed to 500 micromoles photons per square meter per second, there was an almost instantaneous increase in assimilation rate. After this initial increase, there was a secondary increase over the next minute. This secondary increase was more pronounced in high CO(2) (1400 microbars), where assimilation rate was assumed to be limited by the rate of regeneration of ribulose 1,5-bisphosphate (RuBP). It was absent in low CO(2) (75 microbars), where RuBP carboxylase/oxygenase (Rubisco) was assumed to be limiting. It was therefore concluded that it represented an increase in the capacity to regenerate RuBP. This fast-inducing component not only gained full induction rapidly, but also lost it rapidly in low photon flux density (PFD) with a half time of 150 to 200 seconds. It was concluded that in environments with fluctuating PFD, this fast-inducing component is an important factor in determining a leaf's potential for photosynthetic carbon gain. It is especially important during brief periods (<30 seconds) of high PFD that follow moderately long periods (1 to 10 minutes) of low PFD.

Gas Exchange Analysis of the Relative Importance of Stomatal and Biochemical Factors in Photosynthetic Induction in Alocasia macrorrhiza

When leaves of Alocasia macrorrhiza adapted to 10 micromole quanta per square meter per second were transferred to 500 micromole quanta per square meter per second, the rate of photosynthetic CO(2) assimilation increased for over 45 minutes. For the first 10 to 15 minutes, increases in both stomatal conductance and the leaf's photosynthetic capacity were responsible for the increase in assimilation rate. Thereafter, continuing increases in stomatal conductance were almost entirely responsible for further increases in assimilation rate. When conductances were initially high, assimilation rates 1 minute after the increase in photon flux density could be more than six times as high as for similar leaves with initially low conductance. Further increases in assimilation rate in these leaves with high conductance were predominantly due to increases in the induction state at the biochemical level and followed an exponential time course. When stomatal conductances were initially low, then increases in conductance were predominantly responsible for the increases in assimilation rate, with both following a sigmoidal time course. In these leaves, it was important to also consider the effect of cuticular water loss on the calculation of the intracellular partial pressure of CO(2), and an assessment of the relative importance of stomatal conductance differed considerably from one that did not include cuticular water loss.

Observed and modelled stomatal responses to dynamic light environments in the shade plant Alocasia macrorrhiza

Abstract. Dynamic responses of stomatal conductance to lightflecks (15 s to 5 min) were observed in the tropical understory plant Alocasia macrorrhiza. Brief observations were also made on step changes in light, flashing light and short low‐light periods (darkflecks) after stomata had reached steady state conductances in high light. Stomata opened substantially even in response to very short lightflecks, with maximal opening being reached about 20 min after the end of the lightfleck. These responses are compared to those of a semi‐mechanistic stomatal model consisting of three steps in series: a biochemical signal which responds directly to light, producing osmotic changes within the guard cells which, in turn, drive the movement of water into the guard cells. The rate of change of each component was assumed to be given by the difference between the current state of that component and the state of the previous component in the series divided by a characteristic time constant for each step. This model allowed excellent description of observed responses to lightflecks, including the fleck‐length dependence of stomatal opening, the lag between the end of the lightfleck and the time of maximal stomatal conductance and the response to multiple flecks. However, agreement with predicted responses to flashing light and darkflecks was poor. Good agreement could be restored by using different time constants for the initial biochemical step, suggesting that the speed of the initial biochemical response is not constant but dependent on the current physiological state of the stomata. For leaves experiencing predominantly low light, punctuated by relatively short and infrequent periods of high light, this model allows good description of the dynamic changes in stomatal conductance.

Observed and modelled stomatal responses to dynamic light environments in the shade plant Alocasia macrorrhiza

Observed and modelled stomatal responses to dynamic light environments in the shade plant Alocasia macrorrhiza

Photosynthetic Acclimation of Alocasia macrorrhiza (L.) G. Don

The photosynthetic acclimation of Alocasia macrorrhiza (L.) G. Don, a species naturally occurring in deep shade in rainforests, has been studied in relation to a wide range of controlled irradiances during growth (~3-780 �mol photons m-2 s-1 of fluorescent or incandescent light, 10 h light/ 14 h dark). At the maximum growth irradiances, the light- and CO2-saturated rates of O2 evolution per unit leaf area were ~4 times as high as at low irradiance, and approached those of glasshouse-grown spinach. Growth at maximum irradiances reduced the quantum yield of O2 evolution only slightly. Changes in the anatomy of leaf tissue, the ultrastructure of chloroplasts and the composition of chloroplast components accompanied the changes in photosynthetic functional characteristics. At low growth irradiance, palisade cell chloroplasts were preferentially located adjacent to the distal periclinal cell walls and had large granal stacks, and the destacked thylakoids had a very low surface charge density. In contrast, at higher growth irradiance, palisade cell chloroplasts were preferentially located adjacent to the anticlinal cell walls; they had small granal stacks, large stromal space, and a high surface charge density on the destacked thylakoids. The number of chloroplasts per unit section length increased with growth irradiance. Ribulosebisphosphate carboxylase activity per unit leaf area increased markedly with irradiance. Photosystem II, cytochrome f and latent ATPase activity per unit chlorophyll increased to a lesser extent. While the chlorophyll a/chlorophyll b ratio increased substantially with growth irradiance, the chlorophyll content per unit leaf area declined slightly. Our results show that coordinated changes in the structure of leaf tissue, and the organisation and composition of chloroplast components are responsible for Alocasia being capable of acclimation to high as well as low irradiance.

HPLC determination of vitamin A and vitamin D2 in South Pacific root crops

AbstractAn HPLC method was developed for the analysis of α‐carotene, β‐carotene, retinol and vitamin D2. Sweet potato Ipomoea batatas, taro Colocasia esculenta, taro Xanthosoma sagittifolium, giant taro Alocasia macrorrhiza, giant swamp taro Cyrtosperma chamissonis, yam Dioscorea alata and yam D esculenta contained no appreciable amounts of α‐carotene, retinol or vitamin D2 and the amounts of β‐carotene were equivalent to 0‐300 μg kg‐1 retinol in the fresh samples. This small amount, compared with the WHO/FAO adult RDA of 750 μg day‐1, and the virtual absence of vitamin A related eye diseases in the South Pacific region, demonstrates the adequacy of greens and fiuits, and fish coastal areas, in meeting the vitamin A requirement.

Environmental Effects on Photosynthesis, Nitrogen-Use Efficiency, and Metabolite Pools in Leaves of Sun and Shade Plants

Effects of varying light intensity and nitrogen nutrition on photosynthetic physiology and biochemistry were examined in the sun plant Phaseolus vulgaris (common bean) and in the shade plant Alocasia macrorrhiza (Australian rainforest floor species). In both Phaseolus and Alocasia, the differing growth regimes produced large changes in photosynthetic capacity and composition of the photosynthetic apparatus. CO(2)-saturated rates of photosynthesis were linearly related to leaf nitrogen (N) content in both species but photosynthesis per unit leaf N was markedly higher for Phaseolus than for Alocasia. Photosynthetic capacity was also higher in Phaseolus per unit ribulose 1,5-bisphosphate (RuBP) carboxylase (RuBPCase) protein. The leaf content of RuBPCase was linearly dependent on leaf N content in the two species. However, the proportion of leaf N which was RuBPCase was greater in Phaseolus than in Alocasia and was more sensitive to growth conditions, ranging from 6% of leaf N at low light to 20% at high light. In Alocasia, this range was much less, 6 to 11%. However, chlorophyll content was much more sensitive to light intensity in Alocasia. Thus, the RuBPCase/chlorophyll ratio was quite responsive to N availability and light intensity in both species (but for different reasons), ranging from 6 grams per gram for Phaseolus and 2 grams per gram for Alocasia at high leaf N and 1.5 gram per gram for Phaseolus and 0.5 gram per gram for Alocasia at low leaf N. These large changes in the proportions of components of the photosynthetic apparatus had marked effects on the sensitivity of these species to photoinhibition. These environmental effects also caused changes in the absolute levels of metabolites of the photosynthetic carbon reduction cycle. Concentrations of RuBP and P-glycerate were approximately 2-fold higher in high light-grown than low light-grown Phaseolus and Alocasia when expressed on a leaf area basis. However, if metabolite pool sizes are expressed on the basis of the RuBPCase catalytic site concentration, then they were little affected by the marked changes in leaf makeup. There appears to be fundamental differences between these species in the mechanism of sun-shade adaptation and N partitioning in the photosynthetic apparatus that result in significant differences in the N-use efficiency of photosynthesis between Phaseolus and Alocasia but similar RuBPCase:substrate:product ratios despite these differences.

Contribution of Metabolites of Photosynthesis to Postillumination CO2 Assimilation in Response to Lightflects

In the shade plant Alocasia macrorrhiza grown in low light, photosynthetic CO(2) assimilation during a 5 second lightfleck plus postillumination CO(2) assimilation can allow up to 60% more photosynthesis than that which occurs during 5 seconds of steady state light of the same intensity (RL Chazdon, RW Pearcy 1986 Oecologia. 69: 524-531). Metabolites of photosynthesis were measured to determine if the pool of ribulose 1,5-bisphosphate (RuBP) could account for all of the postillumination CO(2) assimilation following a lightfleck in Alocasia. It was found that the pool of triose-P was much larger than that of RuBP and could account for five times more postillumination CO(2) assimilation than could RuBP. The same trend was seen in the sun plant Phaseolus vulgaris when it was grown in the shade. In contrast, sun-grown Alocasia and Phasiolus did not have a large pool of triose-P relative to RuBP following a lightfleck. In sun plants, carbon may rapidly be converted to RuBP in the light whereas in shade plants there may be a restriction in the path between the triose-P and RuBP pools. It is hypothesized that in shade plants the buildup of triose-P rather than RuBP during the lightfleck prevents inhibition of electron transport which may otherwise occur because of competition for ATP between the two kinases of the photosynthetic carbon reduction cycle. Utilization of the triose-P for postillumination CO(2) fixation would require the capacity for significant postillumination ATP synthesis. The extensive grana stacking and large intrathylakoid space which accompanies the high level of chlorophyll in low-light-grown Alocasia could be an important contributing factor to postillumination ATP formation.

Thiamin, Riboflavin, and Nicotinic Acid Contents of Tropical Root Crops from the South Pacific

ABSTRACTThe thiamin, riboflavin, and nicotinic acid contents of sweet potato (Ipomea batatas, taro (Colocasia esculenta), giant taro (Alocasia macrorrhiza), giant swamp taro (Cyrtosperma chamissonis), taro (Xan‐thosoma spp), yam (Dioscorea alata and D. esculenta) were determined for fresh and 40°C dried material obtained from six South Pacific countries. Losses on drying at 40°C for 2‐3 days were 10‐15% for the three vitamins. Sweet potato contained the largest amount of thiamin (40‐120 μg/100g fresh weight) and along with Colocasia esculenta and Xanthosoma spp. the largest amounts of nicotinic acid. The root crops provided inadequate amounts of thiamin, riboflavin, and nicotinic acid with values ranging from 12‐123, 12‐59 and 220‐1310 Hg/100g fresh weight, respectively. Losses on cooking were about the same for all vitamins and root crops, with about a 20% loss on boiling (water retained) or baking and about a 40% loss on boiling (water discarded).

Ascorbic Acid and Dehydroascorbic Acid Content of Tropical Root Crops from the South Pacific

ABSTRACTThe total vitamin C content (ascorbic acid (AA) plus dehydroascorbic acid (DAA) was estimated by HPLC for sweet potato (Ipomoea batatas), taro (Colocasia esculenta), giant taro (Alocasia macrorrhiza), giant swamp taro (Cyrtosperma chamissonis), taro (Xanthosoma spp.), yam (Dioscorea alata), yam (D. esculenta), cassava (Manihot esculenta) and mean values were 23.6, 15.1, 16.9, 15.7, 13.6, 27.5, 20.3, and 14.9 mg/100g fresh weight, respectively. Standard titrimetric and colorimetric methods gave results only for AA which were generally comparable with HPLC. Drying at 40°C caused loss of AA which was not quantitatively converted into DAA. Storage of sweet potato at 25°C and 15°C for 28 days reduced the total vitamin C content by 17% and 15%, respectively; there was no significant decrease at 0°C. Cooking reduced the levels of AA and DAA by up to 70%.

Photosynthetic responses to light variation in rainforest species : I. Induction under constant and fluctuating light conditions.

Photosynthetic induction under constant and fluctuating light conditions was investigated in intact leaves of Alocasia macrorrhiza and Toona australis, two species native to Australian rainforests. When leaves were exposed to saturating light following a long period at low light intensity, an induction period of 25-40 min was required before steady-state photosynthesis was achieved. A long induction period was required regardless of plant growth conditions (high vs. low light) and ambient CO2 concentrations during mesurement. In low-light grown A. macrorrhiza, the initial slope of the relationship between assimilation and internal CO2 pressure increased 7-fold from 30 s following illumination to the end of the induction period. Both stomatal and carboxylation limitations play a role in photosynthetic induction, but carboxylation limitations predominate during the first 6-10 min. In both species, leaf induction state increased 2 to 3-fold during a sequence of five 30-or 60-s lightflecks separated by 2 min of low light. Rates of induction during 60-s lightflecks and during constant illumination were similar. Induction loss in low-light grown leaves of Alocasia macrorrhiza required more than 60 min of continuous exposure to low light conditions. These results suggest that, under forest understory conditions, leaves are at intermediate induction states for most of the day. The ability to utilize sunflecks may therefore be strongly influenced by the ability of leaves to maintain relatively high states of induction during long periods of low light.

Cyrtosperma chamissonis (Araceae) : Ecology, distribution, and economic importance in the South Pacific

The edible aroids, Alocasia macrorrhiza, Amorphophallus paeoniifotius, Colocasia esculenta, and Cyrtosperma chamissonis, are important subsistence plants throughout the Pacific. A survey of floras, ethnographies, and other works indicated significant differences in the distributions and importance of these plants in the three cultural regions of the Pacific. Colocasia esculenta is the major aroid in Polynesia and Melanesia while Cy. chamissonis is the major aroid in Micronesia. Alocasia macrorrhiza is important on only a few islands in western Polynesia and Am. paeoniifolius is nowhere the major aroid. Although the distributions of Co. esculenta and Cy. chamissonis correspond to cultural regions, they are probably determined by ecological factors rather than by the cultural preferences of the people cultivating the plants. The importance of Cy. chamissonis on the low islands and atolls of Micronesia is due to its ability to withstand brackish water and outcompete Co. esculenta under such conditions.

Survival of inoculum of the leaf blight fungus Phytophthora colocasiae infecting taro, Colocasia esculenta in the Solomon Islands

SUMMARY Phytophthora colocasiae was successfully isolated by baiting with detergent‐treated taro leaf discs 8 cm diameter placed on water slurries of soil, on suspensions of macerated infected leaf lesions or on the washings from petioles of harvested plants. Taro root tips, detached or left on corms, were not susceptible to zoospores of P. colocasiae nor were detached root tips of Lupinus angustifolius. Cubes of taro corm used as baits, and agar selective for Phycomycetes which was inoculated directly with soil, both became too heavily overrun by Phythium splendens to allow detection of P. colocasiae. Investigations indicated that inoculum on lesions of detached leaves and in soil remains viable for only a few days. Petiole bases which comprise the bulk of the ‘tops’ used for vegetative propagation, lost detectable natural inoculum rapidly (2 days) if stored dry, but less rapidly (14 days) if planted immediately in the field. Artifically augmenting surface inoculum with naturally produced sporangia considerably extended the periods of detectability, probably by increasing the chances that a few propagules would survive, especially during dry storage. Incubation of inoculated tops in high humidity led to active infection and sporulation on petioles, especially on cut ends, a situation that might be paralleled under suitable moisture conditions in the field. Of several aroid species tested by artificial inoculation only Alocasia macrorrhiza was susceptible. Natural infection of this plant has not been seen, making it an unlikely alternate host of P. colocasiae under field conditions. Thus perennation between taro crops is effected by shortlived surface propagules and possibly also by mycelium within lesions on petioles. Reduction of the former and prevention of the latter might be achieved by dry storage of tops for 2 to 3 wk.

Identification and quantitative determination of the lipids of Alocasia macrorrhiza tubers.

AbstractThe identity, composition and concentration of each of the major lipids found in Alocasia tubers were investigated using a combination of chromatographic procedures. On a weight to weight basis, the neutral lipids, glycolipids and phospholipids comprised 60.5, 19.0 and 20.5% respectively while the total extractable lipids accounted for 0.6% of the dry weight. In addition to the conventional lipid classes of tubers, the presence of tri‐ and tetragalactosyl diglycerides was confirmed. The predominant fatty acid in each lipid class was linoleic acid with palmitic, oleic and linolenic acids being the other ones. In general, a high degree of unsaturation (66%), similar for most tuber lipids, was established for the component fatty acids of Alocasia.

Fatty acid composition of total lipids from some tropical storage organs.

AbstractThe fatty acids of the total lipid extracts made from 10 tropical storage organs (Alocasia macrorrhiza, Colocasia esculenta, Dioscorea alata, D. bulbifera, D. cayensis, D. rotundata, Ipomea batatas, etc.) were studied. The high occurrence of the C18 unsaturated fatty acids (linoleate and linolenate which together contributed over 50 % on average of the total fatty acids), conferred a high level of unsaturation on almost species. Compared with similar storage organs of temperate regions, there was a definite reduction in the degree of unsaturation. This was brought about by a general increase in the intrinsic values of palmitate and oleate.

Cyanogenese der araceen

A mixture of triglochinin ( O-[β- d-glucopyranosyl]-1-cyano-1-hydroxy-2-methylcarboxy-4-carboxy-Δ-1,2(E)-Δ-3,4(Z)-butadiene) and isotriglochinin ( O-[β- d-glucopyranosyl]-1-cyano-1-hydroxy-2-methylcarboxy-4-carboxy-Δ-1,2(E)-Δ-3,4(E)-butadiene) was isolated and identified from young leaves of Alocasia macrorrhiza.

Composition of the photosystems and chloroplast structure in extreme shade plants

Chloroplasts were isolated from leaves of three species of tropical rainforest plants, Alocasia macrorrhiza, Cordyline rubra and Lomandra longifolia; these species are representative of extreme “shade” plants. It was found that shade plant chloroplasts contained 4–5 times more chlorophyll than spinach chloroplasts. Their chlorophyll a/chlorophyll b ratio was 2.3 compared with 2.8 for spinach. Electron micrographs of leaf sections showed that the shade plant chloroplasts contained very large grana stacks. The total length of partitions relative to the total length of stroma lamellae was much higher in Alocasia than in spinach chloroplasts. Freeze-etching of isolated chloroplasts revealed both the small and large particles found in spinach chloroplasts. Despite their increased chlorophyll content, low chlorophyll a/chlorophyll b ratio, and large grana, the shade plant chloroplasts were fragmented with digitonin to yield small fragments (D-144) highly enriched in Photosystem I, and large fragments (D-10) enriched in Photosystem II. The degree of fragmentation of the shade plant chloroplasts was remarkably similar to that of spinach chloroplasts, except that the subchloroplast fragments from the shade plants had lower chlorophyll a/chlorophyll b ratios than the corresponding fragments from spinach. The D-10 fragments from the shade plants had chlorophyll a/chlorophyll b ratios of 1.78-2.00 and the D-144 fragments ratios of 3.54–4.07. We conclude that Photosystems I and II of the shade plants have lower proportions of chlorophyll a to chlorophyll b than the corresponding photosystems of spinach. The lower chlorophyll a/chlorophyll b ratio of shade plant chloroplasts is not due to a significant increase in the ratio of Photosystem II to Photosystem I in these chloroplasts. The extent of grana formation in higher plant chloroplasts appears to be related to the total chlorophyll content of the chloroplast. Grana formation may simply be an means of achieving a higher density of light-harvesting assemblies and hence a more efficient collection of light quanta.

The Growth of Alocasia macrorrhiza (L) Schott Variegata Roots on Murashige and Skoog Medium Supplemented 6-Benzyl Amino Purine (BAP) and Kinetin

The sente variegata plant (Alocasia macrorrhiza variegata) is a species of ornamental taro. The unique leaf color of sente variegata, which is a combination of white and green, attracts ornamental plant lovers for hunting or collecting. There has been no cultivation effort from the ornamental plant suppliers and traders for multiplication purposes until now. Sente variegata is obtained directly from the forest. This activity can cause extinction. Micropropagation efforts using plant tissue culture techniques are needed for commercial and sustainability issues. This study aimed to determine the effect of 6-Benzyl Amino Purine (BAP) and kinetin on the root formation and growth as one step in the shoot multiplication of sente variegata bulb explants. Variations in BAP and kinetin concentrations used separately in this study were 0, 2, 5, and 10 mg. L-1. The results showed that the application of BAP and Kinetin significantly affected the root growth of sente Variegata. Finally, kinetin 10 mg L-1 is the concentration and type of cytokinins recommended for the formation and root growth of sente variegate.

Pottery making in the Yami tribe of Betel Tabago

Pottery making is still practised among the Yami tribe, Botel Tobago, although the artifact has been abandoned at one time or another by the other tribes of the Formosan mainland. According to the economical calender of the Yami, it is done in the month of 'Paruptogun', or September, and restricted to the men who manufacture such earthen ware as the Puraranum (water-jar), Wanga (boilingpot), Waga (earthen bowl), etc.The plastic clay, which is decomposed andesite or agglomerate that prevalent n the island, is obtained from certain points along the valley, and upon being brought to the village, is first passed between the fingers in order to eliminate the small rock's fragments and grits, and kneaded well without adding any sand. As soon as the Yami has finished gathering the clay, the fuel which had been left in the mountains to dry is transported to the sand beach, where it is again dried in the sun.The Yami mould the clay into a well-shaped pot with great ingenuity without employing the potter's wheel. A lump of the prepared clay is shaped with the hands into the form of a cylinder, the round base of which is laid on a leaf of the Raon grass (Alocasia macrorrhiza SCHOTT) and placed upon a board. The worker next pats the pot from the outside with the Paparo (patting club) in one hand, and supporting that part of the spot which is being patted from the inside with a flat stone in the other hand, thus building up the rough shape by gradually thinning and expanding the clay. The roughly made pot is moreover beaten out into shape with the Pipikpik (patting battledore) in one hand and a flat stone in the other. When the pot has acquired the desired shape, the outside is scraped with the Tatari or bamboo stick. The pot is left to dry in the wind, but out of the sun for about three days. The firing place is a cleaned space of ground on the sea-shore, a fine day with little or no wind being chosen. The fuel, which is cut up into lengths of a meter or so, is piled up in the form of a square block on the ground, and the pots are placed on it with their bottoms resting on the fuel laid side by side. More fuel is then added above and around the sides of the pots, and then being fired on the top of the fuel. Pots are baked two or three hours after the fuel is fired. The moulding of the clay and the firing of the pottery require great skill, with the result that the pot is often broken. Consequently, many taboos are observed among the potters in the pottery making season.Explanation of Textfigures.1. Diagrammatic sketch showing the manner of holding the flat, circular stone from the inside of the pot.2. Pipikpik or patting battledore (Left) and Paparo or patting club. (Right).3. Ipamarun-so-waga with section.4. Pasasakuvan-so-waga or mould used for making the Waga or earthen bowl.5. Moulding the clay into a cylinder.6. Adjusting the shape of the pot with the Pipikpik or patting battledore.7. Placing the pots in a depression in the piled fuel preparatory to firing.