A review of dipterocarps - Center for International Forestry Research

Seed Physiology 62
Table 3. Relationship between germination and moisture content during desiccation (Tompsett and Kemp 1996a, b)*.
Species Lowest-safe moisture
content values
(percentage)**
*: Results can be summarised by regression as a straight line if
germination percentage is first transformed into probits;
The basis of desiccation damage
If the basic causes of desiccation damage could be
determined, a way might be found to reduce the effect,
thus enabling better survival of the seed. In this
connection, Nautiyal and Purohit (1985b, c) assessed
various factors for S. robusta seed. The quantity of
nutrients leaking from the seed increased as moisture
content (and germination ability) declined; it was
Slope of probit line (probits
per unit of moisture content
percentage)
Intercept of probit line
(probit percentage
germination)
Shorea leprosula 26 n/a n/a
Shorea argentifolia 28 0.1814 -3.5780
Shorea ferruginea 29 0.1912 -4.8300
Hopea ferrea 30 0.1050 -3.5660
Hopea mengerawan 30 0.1400 -3.6700
Hopea foxworthyi 31 0.0994 -2.5555
Hopea odorata 32 0.1303 -3.6450
Shorea parvifolia 32 n/a n/a
Shorea roxburghii 32 0.1000 -2.7700
Shorea obtusa 33 0.0660 -2.4420
Shorea ovalis 33 0.1816 -5.0550
Cotylelobium melanoxylon 34 0.1303 -3.1790
Vatica mangachapoi 34 0.0919 -3.4460
Cotylelobium burckii 35 0.1400 -3.2200
Parashorea smythiesii 35 0.1743 -4.9920
Shorea macrophylla 35 0.0978 -2.6190
Shorea trapezifolia 37 n/a n/a
Dipterocarpus costatus 38 0.0789 -1.9360
Dipterocarpus obtusifolius 38 0.0584 -2.2470
Dipterocarpus zeylanicus 38 0.1427 -3.8090
Shorea fallax 38 0.0869 -2.2470
Shorea macroptera 38 0.0867 -4.2300
Parashorea tomentella 40 0.2000 -7.1400
Shorea amplexicaulis 40 0.1307 -5.5600
Shorea congestiflora 40 0.0904 -3.6510
Shorea robusta 40 0.1300 -4.2200
Vatica odorata ssp. odorata 41 0.0961 -3.6290
Shorea affinis 42 0.0475 -1.6120
Shorea almon 42 0.1400 -5.4700
Shorea leptoderma 42 0.0460 -2.5280
Dipterocarpus turbinatus 43 0.1300 -5.5300
Dryobalanops lanceolata 43 0.1200 -6.0400
Dryobalanops keithii 50 0.1233 -5.0770
Parashorea malaanonan 50 0.0965 -3.9830
**: LSMC for seeds dried at 10-15% relative humidity and 15-
20°C.
concluded that cellular membranes in the seed had lost
their semi-permeability. However, whether the apparent
loss of semi-permeability was a primary result of
desiccation, or whether it was one aspect of a general
loss of metabolic capability could not be distinguished
from the data obtained. A small decline in the absolute
concentration of nutrients in the seed was observed, but
the significance of this decline was not clear. Protein