Vedas and the Vedic dharma are very old. People of those days are Most unlikely to have any concept of microbes, embryos present in eggs, fruits, and plant seeds, etc. Naturally, the sensible mind canNot help wondering whether people of Vedic times were Really aware that plants & trees are endowed with life.
Permeating the earth, I nourish all living beings with My energy. Becoming the moon, I nourish all plants with the juice of life.
The following mentions the birth of a jiva in these yonis.
अभ्रं भूत्वा मेघो भवति मेघो भूत्वा प्रवर्षति त इह व्रीहियवा ओषधिवनस्पतयस्तिलमाषा इति जायन्तेऽतो वै खलु दुर्निष्प्रपतरं यो यो ह्यन्नमत्ति यो रेतः सिञ्चति तद्भूय एव भवति ॥ ५.१०.६॥
Having become mist, he becomes a cloud, having become a cloud, he rains down. Then he is born as rice and corn, herbs and trees, sesamum. and beans...
प्राचीनशाल औपमन्यवः सत्ययज्ञः पौलुषिरिन्द्रद्युम्नो भाल्लवेयो जनः शार्कराक्ष्यो बुडिल आश्वतराश्विस्ते हैते महाशाला महाश्रोत्रियाः समेत्य मीमाꣳसां चक्रुः को न आत्मा किं ब्रह्मेति ॥ ५.११.१॥
ते ह सम्पादयाञ्चक्रुरुद्दालको वै भगवन्तोऽयमारुणिः सम्प्रतीममात्मानं वैश्वानरमध्येति तꣳ हन्ताभ्यागच्छामेति तꣳ हाभ्याजग्मुः ॥ ५.११.२॥
1.If some one were to strike at the root of this large tree here, it would bleed, but live. If he were to strike at its stem, it would bleed, but live. If he were to strike at its top, it would bleed, but live. Pervaded by the living Self that tree stands firm, drinking in its nourishment and rejoicing;
2.But if the life (the living Self) leaves one of its branches, that branch withers; if it leaves a second, that branch withers; if it leaves a third, that branch withers. If it leaves the whole tree, the whole tree withers . In exactly the same manner, my son, know this.
Adi Shankaracharya’s commentary on verse 2
...That the tree is ensouled by the' Living Self' has been indicated by the phenomena of the flowing of juices and withering of-as shown by the illustration also vouched for the Vedic text; which means that immovable (apparently inanimate) objects (like the tree) are endowed with sentience; and this also shows that there is no truth in the Bauddha and Vaisheika view that' immovable objects are insentient.' -(2)
योनिमन्ये प्रपद्यन्ते शरीरत्वाय देहिनः । स्थाणुमन्येऽनुसंयन्ति यथाकर्म यथाश्रुतम् ॥ ७॥
Some of those who have born with bodies (the human beings), requiring other bodies reach the entry point again (the womb). Some others reach the state of plants (or other stationary objects). All these happen according to their actions, thoughts and knowledge