Ferocactus Acanthodes Research Articles

Nutrient Levels in Cacti-Relation to Nocturnal Acid Accumulation and Growth

The levels of ten essential nutrients and Na in the chlorenchyma and subjacent parenchyma of ten species of cacti were measured along with the maximal rates of nocturnal acid accumulation. Nutrient levels varied considerably among species; also, soil differences between sites affected levels within Opuntia ficus-indica and O. chlorotica. Compared to most agronomic plants, chlorenchyma levels of Ca, Mg, and Mn in cacti tended to be higher and Na lower. Moreover, Ca tended to accumulate in the chlorenchyma with age. The strongest correlation between nutrient level and a metabolic process for the 11 elements tested was with N, where nocturnal acid accumulation tended to be greater when the N level in the chlorenchyma was higher (r2 = 0.39). Hydroponically grown seedlings of Carnegiea gigantea, Ferocactus acanthodes, and Trichocereus chilensis responded to N fertilization, reaching about 90% of their maximal growth rates when provided with N at 0.25 x that in Hoagland's solution (namely, 4 mm nitrate). Nocturnal acid accumulation was negatively correlated with the chlorenchyma Na (r2 = 0.32), which averaged only 28 ppm for O. ficus-indica (the root contained considerably more) and 234 ppm for the other species. Growth of seedlings was 50% reduced at about 100 mm NaCl for F. acanthodes, T. chilensis, and C. gigantea, while variations in P had a relatively small effect.

Spine influences on PAR interception, stem temperature, and nocturnal acid accumulation by cacti

Abstract. The influence of spines on nocturnal acid accumulation was examined for two Crassulacean acid metabolism plants, the barrel cactus Ferocactus acanthodes (Lemaire) Britton & Rose var. lecontei (Engelm.) Lindsay and the cylindropuntia Opuntia bigelovii Engelm. var. bigelovii. The ambient photo‐synthetically active radiation (PAR) required for 90% saturation of nocturnal acid accumulation by O. bigelovii was 23 mol m−2 d−1 for stems that were 32% shaded by spines and 16 mol m−2 d−1 when the spines were removed. For F. acanthodes, 90% saturation occurred for an ambient PAR of 45 mol m−2 d−1 where the stem was 78% shaded by spines and 21 mol m−2 d−1 when the spines were removed. For comparison, the ambient PAR averaged 21 mol m−2 d−1 at various times of the year and stem positions for O. bigelovii fully exposed to solar irradiation. Although spines can reflect some PAR toward the stem surface, their presence decreases the PAR incident on the stem surface, thereby decreasing the nocturnal acid accumulation. For O. bigelovii, periodically removing the spines led to a 60% greater increase in stem volume over 21/2 years. The effect of variation in spine‐shading on stem surface temperature was determined for F. acanthodes using computer simulations and an energy budget model. A substantial reduction in daytime stem temperatures and a smaller increase in night‐time temperatures as the spine‐shading increased had very little influence on nocturnal acid accumulation for both winter and summer days. Thus, the main effect of spines on the metabolism of cacti is apparently to reduce the PAR incident on the stem surface and thereby to reduce productivity.

Height Distributions of Two Species of Cacti in Relation to Rainfall, Seedling Establishment, and Growth

In three populations of Ferocactus acanthodes and two of Carnegiea gigantea, multiple discrete peaks in the height distribution were observed, suggesting that seedling establishment was intermittent. To identify periods of establishment, we determined the relationship between stem height and age for each site, based on observed growth rates in the field, gas-exchange data, and weather records. The average yearly growth for the globular F. acanthodes was relatively constant at about 9 mm yr-1 but for the club-shaped C. gigantea, it increased with age from 2 mm yr-~1 in the first year to 44 mm yr-~1 at 13 yr. In years suitable for establishment, seedlings grow to sufficient size that stored water is not depleted by cuticular transpiration during the ensuing drought. The pattern of such suitable years over the last 3 decades correlated with the measured height distributions when the relation between stem height and age was considered. At a Sonoran Desert site, major peaks in the height distribution were cent...

Low-Temperature Tolerance and Cold Hardening of Cacti

Reduced uptake by the chlorenchyma cells of cacti of a stain (neutral red) was used as an indicator of low-temperature damage resulting from cooling stems in the laboratory. Necrosis set in a few degrees below the temperature at which the fraction of cells accumulating stain was reduced by 50%. Coryphantha vivipara, Opuntia polyacantha, and Pediocactus simpsonii, which range to over 300 m altitude in southern Wyoming, were quite cold tolerant. Relationships among tissue cold sensitivity, morphological features which protect the stems from low temperatures, and the occurrence of species in progressively colder regions were investigated. Differences in tissue cold sensitivity accounted for the approx. = 600 m higher elevational limit of Coryphantha vivipara var. rosea compared to the morphologically similar var. deserti in southern Nevada. In contrast, morphological differences alone could adequately explain the relative northern limits of the columnar cacti Carnegiea gigantea vs Stenocereus gummosus and the barrel cacti Ferocactus acanthodes vs. F. wislizenii in the southwestern United States, as previously indicated using a computer model. Cold hardening in response to decreasing day/night air temperatures was observed for 10 species. A decrease from 50/sup 0//40/sup 0/ to 10/sup 0//0/sup 0/ lowered by 4/sup 0/ the temperature at which themore » fraction of the chlorenchyma cells taking up stain was reduced 50% for both D. rhodacantha and T. candicans, with a half-time for the shift of approx. = 3 d. The tolerance of subzero temperatures and the ability to cold harden allow cacti to range into regions with considerable wintertime freezing.« less

Influences of Photosynthetically Active Radiation on Cladode Orientation, Stem Tilting, and Height of Cacti

Stem orientation and morphology were investigated for 14 species of cacti in Chile, Ecuador, Mexico, and the United States. The interception of photosynthetically active radiation (PAR) was specifically considered for cladodes (flattened stems) of platyopuntias, for tilted cylindrical stems, and in the presence of surrounding vegetation. Terminal cladodes of Opuntia chlorotica had a statistically significant tendency to face north—south at specific sites in the Mojave desert and east—west in the Sonoran desert. There was also a tendency for cladodes of three varieties of O. echios in the Galapagos Islands, Ecuador, to face east—west, while three times more cladodes of O. stricta var. dillenii faced within 15° of east—west than within 15° of north—south in Florida. In all cases, the orientation increased PAR absorption at times of the year favorable for growth. The longitudinal axes of ceroid cacti with multiple stems were vertical in both the northern (Carnegiea gigantea, Lemaireocereus thurberi, and Lophocereus schottii) and southern (Trichocereus chilensis) hemisphere. However, the longitudinal axes of barrel—shaped cacti with single cylindrical stems tended to tilt southward in the northern hemisphere (Ferocactus acanthodes, F. covillei, F. viridescens, and F. wislizenii) and northward in the southern hemisphere (Copiapoa cinerea var. columna—alba, C. lembckei, and Eriosyce ceratistes). Although equatorial tilting can increase the temperature of the apical region for certain cacti in the wintertime, for other species it has relatively little influence of minimum or maximum stem temperatures. Also, it tends to reduce the total amount of PAR intercepted by the sides of stem. Hence, equatorial tilting may not be of adaptive advantage for all cacti. The maximum stem height of O. echios varied 2—fold in a series of communities extending over 16 km on Santa Cruz island in the Galapagos Islands, and the maximum height of T. chilensis varied 4—fold over 12 km in central Chile. Changes in stem height were positively correlated with changes in the height of the surrounding vegetation (r ° .98) and negatively correlated with PAR in the vertical planes of the stems at 2 m (r ° —.96). The diurnal change in tissue acidity of these Crassulacean—acid—metabolism (CAM) plants was 90% light—saturated for a total daily PAR of about 20 mol of quanta.m—2.d—1 which is approximately the average PAR that unshaded vertical stem would receive on clear days. Hence, the increase in height of these cacti accompanying increases in height of the surrounding vegetation helps to insure that they receive adequate PAR. In fact, for these and other cacti, PAR is often limiting for CO2 uptake, even in the high—radiation environment of deserts.

Seedling Establishment of Ferocactus Acanthodes in Relation to Drought

The 30 smallest seedlings of Ferocactus acanthodes (Lem.) Britton & Rose (Cactaceae) at a canyon site in the northwestern Sonoran desert average 2.5 cm in height. Based on field studies of CO2 exchange throughout the year, the estimated time of their germination was late summer 1976. To explain why so little establishment occurred in recent years, the length of lethal drought for seedlings of various ages was calculated from the seedling geometry (volume—to—surface ratio), dehydration tolerance, and transpiration rates. Individual years were identified which had sufficiently long growing seasons relative to the length of the subsequent droughts to allow establishment. Eight of the last 18 yr were found to be suitable for establishment of F. acanthodes, the last year being 1976.

Surface Temperatures of Cacti‐‐Influences of Environmental and Morphological Factors

An energy budget model predicted the average stem surface temperatures of a Mammillaria dioica 9.4 cm tall and a Carnegiea gigantea 5.64 m tall within 1°C of the hourly measured temperatures over 24—h periods. For the ranges of various environmental factors considered in a sensitivity analysis, the average surface temperature of the stem was most influenced by air temperature. Greater diurnal extremes of stem temperature occurred at lower wind velocities. Asymmetrical heating of the stem by direct solar irradiation was clearly evident in the measurements and the simulations. The model was used to study the effect of changes in spine coverage, apical pubescence, stem absorptance, tissue thermal properties, plant height, and diameter on stem surface temperatures. In the absence of spines the average surface temperature of Mammillaria became 1 to 2°C cooler at night and 2 to 6°C warmer during the day. The effect of spines on the simulated diurnal temperature variation was even greater for the apical meristem, which had the most dense coverage of spines. A mat of pubescence additionally protected the apical meristem of Carnegiea and Ferocactus acanthodes, substantially reducing diurnal temperature extremes there. Simulated decreases in the diameter of Carnegiea increased the daily range of temperatures of the apical meristem, suggesting that some adaptive optimization of plant diameter may have occurred. Simulations for the 3 species under the same environmental conditions showed that the lowest stem and apical temperatures occurred for Carnegiea, consistent with its restriction to lower (presumably warmer) elevations than Ferocactus and Mammillaria.

Thermal Energy Exchange Model and Water Loss of a Barrel Cactus, Ferocactus acanthodes

The influences of various diurnal stomatal opening patterns, spines, and ribs on the stem surface temperature and water economy of a CAM succulent, the barrel cactus Ferocactus acanthodes, were examined using an energy budget model. To incorporate energy exchanges by shortwave and longwave irradiation, latent heat, conduction, and convection as well as the heat storage in the massive stem, the plant was subdivided into over 100 internal and external regions in the model. This enabled the average surface temperature to be predicted within 1 C of the measured temperature for both winter and summer days.Reducing the stem water vapor conductance from the values observed in the field to zero caused the average daily stem surface temperature to increase only 0.7 C for a winter day and 0.3 C for a summer day. Thus, latent heat loss does not substantially reduce stem temperature. Although the surface temperatures averaged 18 C warmer for the summer day than for the winter day for a plant 41 cm tall, the temperature dependence of stomatal opening caused the simulated nighttime water loss rates to be about the same for the 2 days.Spines moderated the amplitude of the diurnal temperature changes of the stem surface, since the daily variation was 17 C for the winter day and 25 C for the summer day with spines compared with 23 C and 41 C, respectively, in their simulated absence. Ribs reduced the daytime temperature rise by providing 54% more area for convective heat loss than for a smooth circumscribing surface. In a simulation where both spines and ribs were eliminated, the daytime average surface temperature rose by 5 C.

Water relations and photosynthesis of a barrel cactus, Ferocactus acanthodes, in the Colorado desert.

The structural characteristics, water relations, and photosynthesis of Ferocactus acanthodes (Lemaire) Britton and Rose, a barrel cactus exhibiting Crassulacean acid metabolism (CAM), were examined in its native habitat in the western Colorado desert. Water storage in its succulent stem permitted nighttime stomatal opening ot continue for about 40 days after the soil water potential became less than that of the stem, a period whe the plant would be unable to extract water from the soil. After 7 months of drought and consequent unreplenished water loss from a plant, diurnal stomatal activity was not observed and the stem osmotic pressure was 6.4 bars, more than double the value measured during wet periods with nighttime stomatal opening. F. acanthodes had a shallow root system (mean depth of 8 cm) which responded within 24 h to rainfall.When the nocturnal stem surface temperature was raised from 8.0° C to 35.0° C, the stomatal resistance increased 4-fold, indicating that cool nighttime temperatures are advantageous for gas exchange by F. acanthodes. Moreover, the optimal temperature for CO2 uptake in the dark was only 12.6° C. CO2 uptake at night became maximal for 3.0 mEinsteins cm-2 of photosynthetically active radiation incident during the preceding day, and the minimum number of incident quanta absorbed per CO2 fixed was 68. The transpiration ratio (mass of water transpired/mass of CO2 fixed) had the relatively low value of 70 for an entire year, consistent with values obtained for other CAM plants. The total amount of water annually diverted to the floral structures was about 6% of the stem wet weight. The annual growth increment estimated from the net CO2 assimilation corresponded to about 10% of the stem mass for barrel cacti 34 cm tall, in agreement with measured dimension changes, and indicated that such plants were about 26 years old.

Isolation of D-galactaric acid and isocitric acid from Ferocactus acanthodes Br. et R.

Isolation of D-galactaric acid and isocitric acid from Ferocactus acanthodes Br. et R.