Salak (Salacca zalacca (Gaertner.) Voss.) – The Snakefruit from Indonesia Preliminary Results of an Ecophysiological Study R. Lestari and G. Ebert Fachgebiet Obstbau, Landwirtschaftlich-Gärtnerische Fakultät, Humboldt–Universität zu Berlin INTRODUCTION MATERIALS AND METHODS The genus of Salacca, which is known as SALAK or SNAKE FRUIT, is found naturally in Indonesia and other South Salak seeds cultivar Pondoh were germinated in sand flats in a greenhouse at Berlin-Dahlem. After 1.5 East Asian countries. In Indonesia, salak is widely cultivated in the lowlands throughout the islands. There are many months seedlings with 2 leaves (about 25 cm long) were transferred to single pots (16 x 12 cm), which were SALAK cultivars, each of those has its particular taste and fruit characteristics. An important cultivar for the Indonesian filled with compost: sand = 2:1. The water stress treatments applied to the plants were: (1) Control plants market and very prospective for export is PONDOH. Currently, there is an increasing interest in investigating SALAK (C), sufficient water supply daily; (2) Flooding the plants (F) during the entire measuring period; (3) nd production techniques and postharvest properties in Indonesia. However, very limited studies on the ecophysiological Intermediate drought (ID), watering only once in a week and (4) Drought (D), watering only in the 2 week aspects have been done so far. The objectives of this study are to investigate the effect of water stress on net CO of the study in the greenhouse or without water supply during the period respectively in the growth 2 assimilation rate (P ), stomatal resistance (R ), growth and leaf water potential (Ψ ) of salak seedlings at different chambers. n s l environmental conditions in the greenhouse and in growth chambers. The data of P and R were measured using a portable photosynthesis system (CI-301PS, CID Inc., USA) in n s the greenhouse (GH) and in the chambers (GC). For the experiments in the growth chambers (GC1 and Table 1. Environmental conditions during the measurement in the greenhouse and in the growth chambers GC2), conditions of twelve hours photoperiod were arranged, relative humidity was uncontrolled in GC1 and controlled at 70% in GC2. Shoot length and leaf area were recorded before and after the experiment Location Air Temperature Leaf Temperature PAR* * Relative Humidity CO2 concentration with a ruler and leaf area meter. Dry weight of shoots and roots were determined only for the experiment at (°C) (°C) (µmol m-²s-1) (%) (ppm) GC1. The leaf water potential of 2 –3 fully developed leaves per plant and 2 plants were measured using the Greenhouse (GH) 25 – 43 23 - 47 144 - 2058 13 - 70 258 - 383 scholander bomb at week 6. Except D treatment plants were measured only at week 2 in GC2 and at week 3 Growth Chamber 1 (GC1) 24 - 32 24 - 34 43 - 98 28 - 70 260 - 319 for plants in GC1 namely at wilting conditions. Growth Chamber 2 (GC2) 21 - 26 22 – 27 136 - 253 28 - 70 317 - 441 ** PAR = Photosynthetic Active Radiation RESULTS Fig.1. Net CO assimilation rate (P ) and stomatal resistance (R ) of salak seedlings at different water 2 n s stress conditions (Control (C), Flooded (F), Intermediate Drought (ID) and Drought (D)) in GH, GC1 and GC2 Female Flower GH Salak in Bunches 300,00 3,50 C ID b 3,00 a 250,00 ) 1) b -1 2,50 D s- s 200,00 2 2,00 F -2 a m m- a a l 2 1,50 150,00 o O a 1,00 a m ab C ab b l a a a (m 100,00 a 0,50 a a s a mo a a a a R µ b a a ( 0,00 a a 50,00 a n a a P -0,50 291724 a a 0,00 -1,00 2 9 17 24 Day after treatment Day after treatment Salak Fruit GC1 GC2 Male Flower 3 3 a a ) a 1 a a a a ) 2 2 a a a 1 -²s- b - a s a a ² a ab - 1 a a a a a 2 m 1 b b b a O b Salak Plant ab abab a a a 0 l C 0 ab b a a a a o lCO2 m a a o a c -1 a (µm -1 n (µm P n -2 -2 140,00 P 131,243(a) 3,500 123,130(a) 3,10(a) -3 -3 3,02(a) 120,00 3,000 Shoot Dry Weight(gr) Shoot Growth (cm) 2,54(a) 100,00 Root Dry Weight(gr) 225 225 2,500 C 79,693(a) Leaf Growth (cm²) 200 200 b 80,00 175 2,000 ) 175 ID 1 ) 1,56(b) 150 1 150 -²s- c F 60,00 1,500 a -²s- m 125 125 l m l o 100 bc b 100 35,80(a) o 30,93(a) m D 40,00 30,8(ab) 1,000 0,74(a) 0,72(a) 75 b m (m 75 a a 0,44(a) 0,52(a) (m s b b a b 50 a s a R 50 20,00 0,500 a a a a R b b a a 6,90(b) 25 a a a 25 a a a 0,0(b) a a a a a a a a a a a a 0 0 a a a 0,00 0,000 10 16 23 27 31 36 43 50 FCIDD FCIDD 10 18 24 31 38 45 Treatment day after treatment day after treatment Water treatment Fig. 2. Shoot and leaf growth of salak seedlings Fig.3. Shoot and root dry weight of salak seedlings under different water stress conditions (C, under different water stress conditions (C, F, Net CO2 assimilation rate and stomatal resistance of seedlings in the greenhouse and growth F, ID and D) during 7 weeks in GC1 ID and D) in GC1 chambers P of salak seedlings in GC1 was very low due to the low light intensity in this chamber. The other environmental factors, n i.e. high temperature and low air humidity resulted in a stomatal closure, which caused the decrease of P . No differences 250 n Leaf Growth (cm²) 6 were found between C and P of other stressed plants except F and ID in the middle of study in GC2, D in GC2 and D at 2 n Shoot Growth (cm) 195,04(a) C day 24 in GH (Fig. 1.). D plants wilted and died after 3 weeks in GC1 and after 2 weeks in GC2 indicating the high 200 G -2 -1 susceptibility of plants to drought. R of all plants in GC2 was relatively constant at a low level, i.e. under 45 mmol m s , 2 D s 145,95(a) and it was lower as compared to R of plants in GC1 and GH. Only R of D plants was significantly different compared to 150 k ID s s e R of the treatments in GH and GC. R of ID in the middle of study and F at day 43 were also significantly different s s we F compared to C in GC1, but no difference was found at the end of the study. 100 87,28(a) 6 C 61,51(a) 1 50 28,9(a) GC 23,3(a) 16,0(ab) 3 Ψ 0,9(b) Plant growth and Leaf water potential ( l ) at different plant growth chambers 0 The shoot dry weight of D significantly differed from the other treatments (C, F and ID), but there was no significant FCIDD -2 -1,5 -1 -0,5 0 difference in root dry weight among all treatments in GC1. Shoot length and leaf area of D were significantly lower Water Treatment compared to other treatments (C, F and ID). No significant differences were found of leaf growth for all watering treatment MPa plants growing in GC2 and only shoot growth of D was significantly different compared to those of C and F. Fig. 4. Shoot and leaf growth of salak seedlings Fig. 5. Leaf water potential of salak seedlings under different water stress condition (C, under different water stress conditions In GC1 and GC2, Ψ of F was higher compared to Ψ of C at week 6, while Ψ of ID was lower compared to Ψ of C. F, ID and D) during 6 weeks in GC2 l l l l (C, F, ID and D) in GC1 and GC2 Compared to seedlings growing in GC1 (C, F and ID), Ψ of plants with same treatment growing in GC2 were much lower. l ID of GC2 decreased almost three times compared to C, while ID in GC1 decreased only about half times to C. CONCLUSION We found out that, salak belongs to a group of drought susceptible and flood-tolerant species. The experimental plants wilted within 2-3 weeks of drought, but could stand until 7 weeks flooding conditions. No differences in Pn, Rs and plant growth were found among control, intermediate drought and flooded plants at the end of the study. The stressed plants showed some adaptation abilities to water logging stress, such as a decrease in leaf size and the formation of new roots..