Survival and Growth Rates of Rafted Sago (Metroxylon sagu Rottboell) Suckers as Influenced by Size and Trimming under Nursery Conditions

In Mindanao, the sago palms (Metroxylon sagu Rottb.) grow in the marsh as semi-wild stands. Attempts to grow suckers in garden soils showed low survival. This study aimed to determine the survival and growth rates of suckers based on stem base diameter (small, 4–9 cm, and large, 10–15 cm), trimmed or untrimmed, rafted for 0, 1, 2, and 3 months in the wild (Agusan del Sur) prior to polybagging in the nursery (Davao City). Holding suckers in bamboo rafts by floating in waterways for up to three months and trimmed of their leaves were shown to improve survival in the nursery. During rafting, a mean survival rate of 81% for trimmed suckers (both large and small) was observed when rafted for a month, but survival dropped to 40% when extended to three months. Untrimmed large and small suckers exhibited 60% mortality after a month of rafting. When extended to three months, large suckers were affected with a low 6% survival. In the nursery, rafted suckers (one or two months) did not vary with control (no rafting) in terms of survival of trimmed suckers. Rafting for three months improved survival rates to 62% for large and 74% for small samples. For untrimmed suckers, large and small suckers in rafts for three months obtained 100% and 67% survival, respectively; while 88% for small suckers for two months. Trimmed suckers rafted longest produced higher leaf count than non-rafted suckers regardless of base size

Nutrient Status of Nipa from Semi-Wild Stands in Selected Areas of Mindanao, Philippines

Nipa (Nypa fruticans Wurmb.) is a potential source of biofuel from its sap. Increasing sap yield requires understanding nutrient requirements of this palm necessary for cultural management practices. Hence, the nutrient status of nipa in its natural habitats (Western, Northern, Eastern, and Southern Mindanao) were determined to establish critical levels of essential elements using soil and leaf analyses. Results revealed that nipa palms thrived in a wide variety of soils from clayey, loamy to sandy clay loam types. Elemental variations were observed across sampling sites owing to their locations in the estuaries, human activities, and soil pH. Exchangeable bases Na, Ca, Mg, and K varied considerably across areas affecting leaf levels of nipa. However, leaf B levels were shown to be regulated even at toxicity levels of B in the soil. These growing conditions indicate that nipa palm can tolerate highly variable physico-chemical factors that exist in the estuaries. The critical levels of the essential elements in the leaf tissue are estimated as follows: 1.30±0.30% N, 0.13±0.03% P, 0.82±0.14% K, 0.12±0.29% Ca, 0.03±0.03% Mg, 0.16±0.13% Na, 0.53±0.10% S, 0.70±0.10 mg/ kg Cu, 4.30±0.90 mg/kg Zn, 20.00±2.30 mg/kg Fe, 64.20±31.70 mg/kg Mn, and 4.40±1.70% B. These leaf nutrient levels will serve as a basis for fertilizer formulation in nutrient management in the future

Nutrient Status of Nipa (Nypa fruticans Wurmb.) in Selected Areas of Mindanao, the Philippines

Nipa (Nypa fruticans Wurmb.) is a potential source of biofuel which requires the understanding the palm’s nutrition in order to increase sap yield. Initial baseline data on the nutrient levels of nipa were determined from its natural habitats in Mindanao using foliar analysis. Results revealed that nipa palms thrived in a wide variety of soils from clayey, loamy to sandy clay loam types. Elemental variations were observed across sampling sites owing to their locations in the estuaries, human activities, and soil pH. Leaf B levels were shown to be regulated even at extremely high levels in the soil. The nutrient levels in the leaf tissue using leaf rank 2 are as follows: 1.34±0.30% N, 0.13±0.03% P, 0.82±0.14% K, 0.03±0.02% Ca, 0.03±0.03% Mg, 0.16±0.13% Na, 0.53±0.12% S, 0.70±0.11 mg/kg Cu, 4.33±0.94 mg/kg Zn, 20.00±2.35 mg/kg Fe, 64.22±31.74 mg/kg Mn, and 4.45±1.67 mg/kg B. When compared across leaf ranks, mobile elements K and Mg were significantly higher in the youngest fully opened leaf rank 1. For Mn, leaf rank 3 was significantly higher than leaf rank 1, but leaf rank 2 did not vary with either leaf ranks. It is recommended to use leaf rank 2 for foliar analysis on the basis of its intermediate physiological age. Also, Cl level was higher compared to other elements indicating tolerance to saline conditions. Keywords: foliar analyses · leaf ranks · Nypa fruticans · nutrient

The Flowering Habit of Nipa (Nypa fruticans Wurmb.) in Semi-wild Stands of the Davao Region, Philippines

Observations on the flowering characteristics of nipa (Nypa fruticans Wurmb.) were carried out on at least 70 randomly selected palms in various semi-wild stands found in the Davao Region, Philippines (i.e., Bago Aplaya, Ecoland, and Talomo) from April 2010 until February 2011. The developmental stages of inflorescence were identified, described in detail, and arbitrarily divided according to morphological changes exhibited by the inflorescence. These developmental stages are as follows: emergence (E) stage, stage 2 (S2), pre-anthesis (PA) stage, and the antheses stage, which is divided into the female receptivity (F) stage and the male anthesis (M) stage. Among the parameters measured for each stage include the length of the inflorescence from base to tip, the number and length of staminate rachillae, and the number of female flowers. For morphological characteristics comparison of this monoecious inflorescence, different stands in Carmen, Davao del Norte, were observed. The Carmen stands were significantly more fecund compared to the Davao City stands. The former had more female flower count (61 vs. 58 per pistillate head) and more staminate rachilla count (33 vs. 17 spikes) than the latter. The final inflorescence length in Carmen was significantly taller than in Davao City (117.5 cm vs. 84.3 cm), suggesting that the plants in the former had longer tapping potential for sap production. The results have implications toward the future program of nipa hybridization to produce better varieties

Infructescence Development and Fruit Characterization of Nipa (Nypa fruticans Wurmb.) from the Semi-Wild Stands of Davao Region, Philippines

The potential use of nipa (Nypa fruticans Wurmb.) as a source of bioethanol underscores the importance of understanding its infructescence (fruiting head) development beginning at female anthesis. Manual pollinationset-ups showed that stigmatic receptivity spanned 48 h with a peak at 36 h after onset of female anthesis. Weekly observations according to morphological changes at fruit set are categorized as follows: stage 1 is distinguished by the gradual hardening of exocarp and browning of fruits in the infructescence. The fruit color turned dark brown as development proceeded to stage 2 wherein some carpels fused forming bigger fruit. At stage 3, the infructescence began to bend owing to its weight with fruit color intensified to darker brown. At 21 weeks from female anthesis, the fruit head reaches its peak of rapid growth. The hanging of infructescence ensued at stage 4 that ultimately touched the ground at stage 5. This indicates full maturity at 25 weeks from the onset of female anthesis. In a separate study to characterize fruit development, fruit shape appears to be influenced by position in the infructescence rather than environmental conditions. Fruit samples categorized as developed had mostly spherical shape. They were likely located in strategic positions (polar end and equatorial region) of the infructescence which emerged first during female anthesis. A very dark brown hue indicated full fruit maturity

Infructescence Development and Seed Characterization of Nipa Palm from Different Semi-Wild Stands of Davao Region, Southern Philippines

The versatility of nipa even under unstable environmental conditions and its potential use as source of bioethanol underscore the importance of understanding the fruit development of the palm. Female anthesis served as the reference point for determining the age of infructescence (fruit head). Weekly observations categorized according to morphological changes showed that Stage 1 is distinguished by a hard brown seed with dark brown tips. Stage 2 is characterized by seeds of even brown hue with some carpels fused forming bigger seed. At Stage 3, the infructescence began to bend owing to its weight with seeds having brown color with darker hue. At 21 weeks from female anthesis, the fruit head reaches its peak of rapid growth, which may also level off photosynthate demand. This suggests a halt to being a ‘sink’ in the succeeding stages. At Stage 4, the infructescence was already bending halfway the ground level. At Stage 5, the fruit head finally touched the ground. This indicates full maturity at 25 weeks from onset of female anthesis. In a separate study, environmental variability did not show statistical differences on seed morphometrics. However, position of seeds in the infructescence significantly affected viability. Seeds, if spherical, are considered viable and were located in the polar end opposite the peduncle and in the equatorial region. Dark brown seeds indicate full maturity. This study would be of value in the future as reference for seed maturity index, variability tests, and description of different stages for timing sap collection during tapping

Structured Populations of Critically Endangered Yellow Water Lily (Nuphar shimadai Hayata, Nymphaeaceae)

Yellow water lily (Nuphar shimadai Hayata) is a critically endangered species in Taiwan. Here, we examined genetic structures of four extant populations, WP, GPa, GPb and GPn, using 39 simple sequence repeat (SSR) markers. Positive genetic correlation was observed within 50 m, beyond which no correlation was detected due to isolation by distance according to Mantel correlogram. This suggests a significant genetic structuring of the species. Besides, multilocus genotype (MLG) analysis revealed that GPa was a panmictic population and the species’ putative center of origin. Genetic exchange was observed between GPa and GPb populations, which likely resulted from their geographic proximity. Nevertheless, there was a strong asymmetric migration detected from GPa to WP, but a recent genetic barrier prevented dispersal further northward (WP). Geneland estimated the best number of clusters as K = 2, where WP distinctly separated from the rest of the populations. In STRUCTURE output of K = 3, a third cluster was abundant only in WP. We suggest to consider GPn and WP as separate conservation units, being far from GPa. There is indeed a need to investigate these populations; as predicted, Ne = 1.6 to 3.0 is considered low and that may put the species at risk of extinction