Effects of Teramnus labialis (L.f.) Spreng seed cryopreservation on subsequent seed and seedling growth and biochemistry

Teramnus labialis (L.f.) Spreng is a legume that plays an important role in agriculture, due to its use as animal feed and its role as an enhancer of soil physicochemical conditions. However, given previous reports on the effects of seed cryopreservation on seedling vigor and biochemistry in a number of species, the present study looked at the effects of T. labialis seed cryopreservation on subsequent seed and seedling [0–28 days post seed exposure to liquid nitrogen (LN)], growth (germination, seedling length and fresh and dry mass) and biochemistry (chlorophyll, aldehyde, phenolic and protein levels). The seeds were intact in terms of macrostructure after exposure to LN, however, there was a significant (3.5-fold) increase in electrolyte leakage during imbibition. Seedling emergence was also improved by cryostorage during the 1st week of culture (4.1-fold increase) and at 28 days (2.5-fold increase). Consequently, seedling growth (in terms of plantlet length, and fresh and dry mass) was superior in seedlings arising from cryopreserved seed, but this stimulatory effect was more evident at 14 than 28 days of culture. An increase in malondialdehyde levels in cryopreserved seeds is most likely a consequence of damage to the external seed structures following cooling and rewarming, while the rise in cell wall-linked phenolics and aldehydes in roots of seedlings produced from cryopreserved seeds could be linked to water and nutrient stress brought about by greater root growth.